The escalating global challenges of food security,waste management,and environmental sustainability have necessitated the application of novel green approaches to utilize agro-industrial food waste as a valuable biore...The escalating global challenges of food security,waste management,and environmental sustainability have necessitated the application of novel green approaches to utilize agro-industrial food waste as a valuable bioresource.Enzymatic conversion of food waste into high-value bioproducts emerges as one of the promising solutions to address these issues.The current review explores the critical role of enzymes in facilitating the conversion of diverse agro-industrial residues,including those from plants and animals,into biochemicals and functional ingredients.The current review evaluates the environmental and economic benefits of enzyme-mediated bioconversion processes,underlining the circular economy paradigm,which prioritizes resource efficiency and waste minimization.The enzyme production from diverse plant and animal-based food wastes as raw materials has been highlighted beside the description of different bioproducts from food waste using enzymes and the integration of enzymatic bioprocessing.The economic analysis and case studies of the enzyme-mediated processes for biochemical production from food waste have also been emphasized.By harnessing the synergistic potential of enzymes and circular economy principles,the bioconversion of agro-industrial food waste into novel bioproducts presents a viable pathway toward sustainable resource utilization and a circular bioeconomy.展开更多
Prodigiosin is a secondary metabolite mainly produced at 30°C in Serratia marcescens,but it can hardly be synthetized at 37°C or higher.In this study,we provide insight into the metabolic regulation of prodi...Prodigiosin is a secondary metabolite mainly produced at 30°C in Serratia marcescens,but it can hardly be synthetized at 37°C or higher.In this study,we provide insight into the metabolic regulation of prodigiosin synthesis in response to temperature through transcriptome sequencing.The analysis of the function of differentially expressed genes suggested that temperature resulted in significant alteration of the metabolic pathways between 30 and 37°C.Specifically,30°C favored transcriptional expression of the pig gene cluster.At the same time,the carbon flux was redistributed to pathways of pyruvate,proline,serine,especially homoserine,cystathionine,homocysteine,methionine,and s-adenosylmethionine metabolism,all involved in prodigiosin biosynthesis,and was finally increased towards the prodigiosin synthesis pathway in S.marcescens at 30°C.Interestingly,results further confirmed increased transcriptional level of five regulators(LuxS,RpoS,Hfq,EepR,CRP),and decreased content of hexS through qPCR.Finally,successful co-overexpression of mmuM and metK,related to homocysteine,methionine,and s-adenosylmethionine metabolism,in the chromosome of JNB5-1(JNB5-1/MK)resulted in increased prodigiosin titer up to 7.57 g/L in JNB5-1/MK at 30°C,which was 41.2%higher than that in JNB5-1.Our transcriptome analysis provides further insight into the strain’s response to temperature changes at the transcription level,which is of great significance for improving the production of prodigiosin.展开更多
The aim of this work was to study the efficiency of native lignocellulolytic enzymes obtained from isolated bacteria towards enhanced bioethanol production from lignocellulosic biomass.Maximum cellulose(199.33±0....The aim of this work was to study the efficiency of native lignocellulolytic enzymes obtained from isolated bacteria towards enhanced bioethanol production from lignocellulosic biomass.Maximum cellulose(199.33±0.2 mg/g)and hemicellulose(62.21±0.22 mg/g)content was measured from rice straw in alkali condition compared to acid and biological pretreatment,while significant lignin removal has been observed in biological pretreatment.Saccharification of rice straw using isolated cellulase–xylanase enzymes exhibited 60.33%production of total reducing sugar obtained by commercial cellulase–xylanase cocktail.Maximum glucose,xylose,and total reducing sugar yield of 309±0.32,190.7±0.42,and 499.7±0.37 mg/g,respec-tively,at 37.5℃,pH-7,rice straw concentration of 2.5 g/100 mL,enzyme loading 175μl,and incubation period 42 h by com-mercial cellulase–xylanase enzyme mediated hydrolysis.While in case of using the native cellulase–xylanase cocktail from the isolated bacterial strains,highest yields of glucose,xylose and total reducing sugar production was 253.52±0.56 mg/g,47.94±0.78 mg/g,and 301.46±0.67 mg/g,respectively.While applying the isolated enzymes on alkali-pretreated rice straw,bioethanol concentration of around 32.57±0.25 g/L was recorded after the simultaneous saccharification and fermentation by Saccharomyces cerevisiae.The above mentioned bioethanol concentration was obtained at a process parameter of temperature 35℃,incubation time 58 h,and pH 5.5 for isolated cellulase–xylanase enzymes.A maximum bioethanol concentration using isolated cellulase–xylanase enzymes was nearly 93.89%of bioethanol concentration(34.69±0.28 g/L)obtained using commercial cellulase–xylanase.The present study interpreted that the cutting-edge approach for the native enzymes along with metabolic engineering of the isolated bacteria could be promising towards enhanced bioethanol production.展开更多
White biotechnology uses enzymes and microorganisms to produce value-added chemicals from renewable sources.White biotechnology provides valuable components for the food,pharmaceutical,agricultural sectors as well as ...White biotechnology uses enzymes and microorganisms to produce value-added chemicals from renewable sources.White biotechnology provides valuable components for the food,pharmaceutical,agricultural sectors as well as other industries.Metabolic diversity in fungi,yeast,and bacteria can be exploited to produce food additives and other industrial products.This is an interesting topic for those interested in screening and metabolic testing of microorganisms,industrial biotechnology,fermentation technology,and the biological products research community.The use of microbial-derived compounds has a long history in the food industry,and compounds such as flavorings,essential amino acids,poly-unsaturated fatty acids,organic acids,gelling,etc.can be obtained from microbial sources.Also,the role of microbes in human health and well-being cannot be ignored.Microbes produce primary metabolites such as vitamins,nucleotides,and amino acids,as well as secondary metabolites.These secondary metabolites are used to make many drugs.In agriculture,microbes are also used to make fertilizers and biological pesticides.This paper reviews the types of bio-products obtained through biotechnology and the barriers and challenges of white biotechnology.展开更多
In recent times,the microalga Chlorella vulgaris has attracted significant attention due to its multifaceted applications in diverse disciplines.Nonetheless,discrepancies in growth rates and biomass yield are observed...In recent times,the microalga Chlorella vulgaris has attracted significant attention due to its multifaceted applications in diverse disciplines.Nonetheless,discrepancies in growth rates and biomass yield are observed across freshwater and saline environments.This research was designed to elucidate the impacts of varying concentrations ofNaHCO_(3),NPK fertilizer,and NaCl on the proliferation of Chlorella vulgaris cultivated in 288L plastic bottle bioreactors,ensuring optimal light exposure and aeration for algal propagation.Biomass quantifications were executed tri-weekly,utilizing metrics such as optical density(OD)and biomass concentration(mg/L).Post a 30-day cultivation period,the findings revealed that optimal biomass was attained with an augmentation of 30 mg/LNaHCO_(3) and 100 mg/L NPK.Remarkably,the alga manifested resilience to escalating salinity levels,recording a peak biomass of 1036 mg/L upon the introduction of 20 g/L NaCl.Moreover,the research underscored a robust correlation between optical density(OD)and biomass concentration(mg/L)amidst diverse salinity regimes,underscoring the criticality of these parameters in the proliferation of Chlorella vulgaris.展开更多
Escherichia coli contains 12 chaperone-usher operons,including 64 genes,used for biosynthesis and assembly of various fimbriae which consume a lot of energy and material.In this study,each of the 12 operons was delete...Escherichia coli contains 12 chaperone-usher operons,including 64 genes,used for biosynthesis and assembly of various fimbriae which consume a lot of energy and material.In this study,each of the 12 operons was deleted in an L-threonine-producing E.coli strain TWF001,and the resulting 12 deletion mutants produced more L-threonine than TWF001 after 16 or 24 h cultivation.Therefore,the 12 chaperone-usher operons were deleted in different combinations,resulting in 11 strain mutants which lack at least 2 operons.The cell growth and L-threonine production of these 11 mutants were determined.Among these 11 mutants,TWK021 in which 10 chaperone-usher operons were deleted,showed the highest L-threonine production.TWK021 produced 15.75 g L-threonine from 40 g glucose after 36 h cultivation.The conversion rate of glucose to L-threonine reached 0.394 g/g in TWK021,which is 32.2%higher than the control strain TWF001.These results suggest that the fimbria lacking E.coli TWK021 is a good host for efficient production of L-threonine.展开更多
The ribosome-binding site(RBS)in the 5′untranslated region is recognized by 16S rRNA to start translation and is an essential element of the gene expression system.RBSs have been widely applied in regulating gene exp...The ribosome-binding site(RBS)in the 5′untranslated region is recognized by 16S rRNA to start translation and is an essential element of the gene expression system.RBSs have been widely applied in regulating gene expression in various scenarios,including Gram-negative or Gram-positive bacteria.Here,we first rationally designed and constructed an RBS mutant library containing 66 RBSs.The strength of these RBSs in E.coli and C.glutamicum was characterized individually.The RBS strength spanned about 200 and 15 times in the two species,respectively.The strength of RBSs in C.glutamicum was generally lower than that of in E.coli.A total of 18 RBSs showed similar strength(within twofold differences)between the species in our study,and the correlation analysis of the strength of RBSs between E.coli and C.glutamicum(R^(2)=0.7483)revealed that these RBSs can be used across species.The sequence analysis revealed that the RBS region with two Ts stated was beneficial for RBS to function cross-species.The RBS characterized here can be used to precisely regulate gene expression in both hosts,and the characteristics of cross-species RBSs provide basic information for RBS rational design.展开更多
Wastewaters from various process industries,namely food and agricultural,sugar mill,brewery,milk,vegetable and fruit,and meat and fsheries processing industries and their wastewater efuents contain nutrients,organic m...Wastewaters from various process industries,namely food and agricultural,sugar mill,brewery,milk,vegetable and fruit,and meat and fsheries processing industries and their wastewater efuents contain nutrients,organic matter,inorganic,heavy metals,suspended solids,and pathogens.The discharges of non-treated wastewater enter the nearby aquatic ecosystem(e.g.,lakes,rivers)and are a signifcant concern due to the presence of diferent nutrients,competing ions and C containing pollutants.It causes excessive growth of algae,loss of habitat/species,and other negative impacts on human health/environment.In the present review,diferent treatment approaches have been discussed in utilizing these nutrients to synthesize value-added products such as biopolymer,biofuel,pigment,organic acid,or enzymes.These biopolymers can be used to prepare various food products/packaging materials.Dextran,chitosan,carrageenan,alginate,and pectin are good examples of non-food biopolymers.Besides these products,poly-β-hydroxybutyrate(PHB)synthesis from wastewater nutrients is reported as a new source of bio-nanocomposite materials/biopolymer-based coatings.In this review,the diferent treatment approaches are discussed,which are being used worldwide for the removal/recovery of nutrients,toxic pollutants,and the potential resource recovery of value-added products from wastewater.展开更多
“In silico organisms”are computational genome-scale metabolic models used in systems and synthetic biology developed by constraint-based metabolic simulations using multi-omics and phenotypic data.The quality of the...“In silico organisms”are computational genome-scale metabolic models used in systems and synthetic biology developed by constraint-based metabolic simulations using multi-omics and phenotypic data.The quality of these models is hidden because of the limited availability of genomic information and genome-scale metabolic reconstruction methods.In this review,237 manually curated genome-scale models for various organisms with industrial and clinical significance were comprehensively reviewed,and their modelling information was tabulated based on literature.This review provides a comprehensive summary of potential applications of systems biology in biotechnology and biomedical research.Their broad applicability has been explored in the process of model improvement and design of experiments in metabolic design and drug development.This review summarizes their recent advances,challenges,and practical applications in Gram-negative bacteria,Gram-positive bacteria,archaea,fungi,algae,plants,and animals.Genome-scale models of microbes have been reviewed to address their various applications in metabolic systems engineering,strain optimization,bioremediation,biomanufacturing,and personalized systems medicine.Several models have been explored to understand the molecular mechanisms underlying pathogenesis,virulence,host-microbe interactions,and metabolic crosstalk.This review provides an overview of the current knowledge on human metabolic reconstructions and their important roles in human,microbiota-related,and complex metabolic disorders.Genome-scale models of human and animal metals offer ethical alternatives to the traditional animal testing methods.Current progress in systems biology research will lead to the development of indispensable databases,computational tools,and analytical platforms.This will strengthen data-driven discovery and facilitate integration of biological information into living systems.展开更多
UDP-sugars,as active forms of monosaccharides,play integral roles in glycosylation and biosynthesis of polysaccharides.Although enzymatic catalysis has achieved great process,the comparatively low productivity and the...UDP-sugars,as active forms of monosaccharides,play integral roles in glycosylation and biosynthesis of polysaccharides.Although enzymatic catalysis has achieved great process,the comparatively low productivity and the time-consuming enzyme purification processes restricted its practical applications.Here,we developed two CipA-dependent enzyme immobiliza-tion systems for synthesis of UDP-GlcNAc and UDP-GlcA.Initially,we selected and identified the enzyme combinations of PpAmgK and SeGlmU for UDP-GlcNAc(3.19 mM)synthesis,and AtGlcAK and BlUSP for UDP-GlcA(1.83 mM)synthesis.After optimizing the molar ratios of substrates,the production of UDP-GlcNAc and UDP-GlcA increased to 17.33 mM and 9.03 mM when setting UTP:GlcNAc:ATP and UTP:GlcA:ATP as 1:1:1 and 1:2:1,respectively.Then,the polyphosphokinase SePPK for recycling ADP and PPi was introduced,resulting in a significant increase in UDP-GlcNAc(29.33 mM)and UDP-GlcA(20.87 mM).Eventually,the CipA-based immobilization systems were developed for repetitive catalysis.The combinations of PSK-(G_(4)S)_(3)-CipA and CipA-(G_(4)S)_(3)-ABK yielded the comparable productions of UDP-GlcNAc(28.66 mM,17.40 g/L)and UDP-GlcA(20.34 mM,11.80 g/L)within 75 min.This study presents a convenient and reusable CipA-based enzyme immobilization system for synthesis of UDP-sugars,showing great potential for enzymatic production of UDP-GlcNAc and UDP-GlcA.展开更多
Due to abundant availability,biofuel production from bamboo residues is gaining popularity.Bamboo biomass and its residues are widely available in the north-eastern part of India,which can be sustainably exploited for...Due to abundant availability,biofuel production from bamboo residues is gaining popularity.Bamboo biomass and its residues are widely available in the north-eastern part of India,which can be sustainably exploited for green energy production.The aim of the present study was to evaluate the pretreatments of dewaxed bamboo residues with dilute alkali(NaOH),and dilute acid,and the effect of pretreatment on biomass hydrolysis was performed with a commercial enzyme(Zytex).Results showed that maximum fermentable sugars were 490 mg/g obtained from 10%biomass with 0.6%(w/v)of alkali,and acid pretreated biomass produced 320 mg/g of sugars from 2%(w/v)acid with 10%biomass.Changes in biomass structure during the pretreatment process are correlated with FTIR,SEM,and component analysis for lignin,cellulose,and hemicelluloses.Fermentation studies of the hydrolysate showed that the yield of ethanol was 77%of the theoretical maximum at 36 h.Results indicate the scope of utilization of bamboo residues as substrates for biofuels,and alkaline pretreatment is an effective pretreatment process for bioethanol production.展开更多
Degradation of pendimethalin by microorganisms is an approach seeking more attention nowadays.This study aims to isolate a new strain of Planococcus,which is capable of degrading pendimethalin from the soil in rice fi...Degradation of pendimethalin by microorganisms is an approach seeking more attention nowadays.This study aims to isolate a new strain of Planococcus,which is capable of degrading pendimethalin from the soil in rice field.Identification of this coccus bacterium was done by phylogenetic analysis of 16S rRNA gene sequence.Strain PD6 was found to grow potentially on pendimethalin supplemented minimal salt medium and degraded 50 mg L^(-1) pendimethalin in monosubstrate system.Fourier transform infrared(FTIR)spectroscopy was performed to check degradation of pendimethalin by Planococcus,which was demonstrated by changing chemical bonding and stretching patterns.This study was further extended to predict possible first enzyme of pendimethalin-degradation pathway.Molecular docking was performed to check efficient binding of dehydrogenase with pendimethalin.This strain of Planococcus degraded pendimethalin with relatively high efficiency in minimal salt media and is presented as another possible bacterium other than species of Bacillus and Pseudomonas which are already demonstrated as potential in vitro pendimethalin-degrading bacteria.Moreover,docking reveals that dehydrogenases having more chance to prove as first regulatory enzyme of pendimethalin-degradation pathway.展开更多
In this study,a total of 1125 actinobacteria were isolated from the selected mangrove species:Avicennia marina,Rhizopora mucronata and Ceriops tagal from three study stations viz.,Minnie Bay,Carbyn’s Cove and Burmana...In this study,a total of 1125 actinobacteria were isolated from the selected mangrove species:Avicennia marina,Rhizopora mucronata and Ceriops tagal from three study stations viz.,Minnie Bay,Carbyn’s Cove and Burmanallah.Among these three stations,the highest number of actinobacteria was recorded in Carbyn’s Cove(64.97%),followed by(25.51%)at Burmanallah and the minimum of(9.51%)was recorded in Minnie Bay.Maximum number of actinobacteria was recorded from Ceriops tagal(40.44%)than the other selected mangrove species Avicennia marina(34.13%)and Rhizopora mucronata(25.42%).Among the 1,125 mangrove-associated actinobacteria,103 morphologically different isolates from the Minnie Bay station was selected for the further characterization studies.In antibacterial assay,30.11%of the isolates revealed inhibitory activ-ity against all tested clinical pathogens and 65%isolates displayed inhibitory activity against minimum of 04 tested clinical pathogens.Growth survival studies of the actinobacterial isolates also accomplished to withstand in varied NaCl and pH levels.Of 103 isolates,all were found to synthesize gelatinase enzyme,73 isolates demonstrated amylolytic activity,38 isolates exhibited proteolytic and 63 isolates displayed urease activity.Interestingly,56 isolates exhibited excellent DNase activity and 71 isolates revealed positive for l-asparaginase production.To our recognition,11 isolates exhibited constructive results in the production of 06 extracellular enzymes of industrial importance.Of 103 isolates,48 isolates were confirmed by molecular level identification.Based on the phylogenetic analysis,the isolates were categorized under the genera:Strep-tomyces,Nocardiopsis,Salinispora and Actinomadura.展开更多
Bioelectrochemical systems(BESs)are a new and emerging technology in the field of fermentation technology.Electrical energy was provided externally to the microbial electrolysis cells(MECs)to generate hydrogen or valu...Bioelectrochemical systems(BESs)are a new and emerging technology in the field of fermentation technology.Electrical energy was provided externally to the microbial electrolysis cells(MECs)to generate hydrogen or value-added chemicals,including caustic,formic acid,acetic acid,and peroxide.Also,BES was designed to recover nutrients,metals or remove recalcitrant compounds.The variety of naturally existing microorganisms and enzymes act as a biocatalyst to induce poten-tial differences amid the electrodes.BESs can be performed with non-catalyzed electrodes(both anode and cathode)under favorable circumstances,unlike conventional fuel cells.In recent years,value-added chemical producing microbial electrosyn-thesis(MES)technology has intensely broadened the prospect for BES.An additional strategy includes the introduction of innovative technologies that help with the manufacturing of alternative materials for electrode preparation,ion-exchange membranes,and pioneering designs.Because of this,BES is emerging as a promising technology.This article deliberates recent signs of progress in BESs so far,focusing on their diverse applications beyond electricity generation and resulting performance.展开更多
Omega-3 fatty acids are polyunsaturated fatty acids that are vital for human food consumption and metabolism.Eicosapen-taenoic acid(EPA)and docosahexaenoic acid(DHA),two long-chain polyunsaturated fatty acids(LC-PUFAs...Omega-3 fatty acids are polyunsaturated fatty acids that are vital for human food consumption and metabolism.Eicosapen-taenoic acid(EPA)and docosahexaenoic acid(DHA),two long-chain polyunsaturated fatty acids(LC-PUFAs),are primarily obtained from diatoms in the oceanic food web.Though microalgae are the main producers of EPA and DHA,but currently,only few algal strains are known to produce large levels of EPA and DHA.The demand for nutraceuticals has significantly increased because of people’s increased awareness and health consciousness.Due to foods being the concentrated supply of omega-3 PUFAs(polyunsaturated fatty acids),this has increased the demands on aquatic sources of n-3 PUFAs.Micro-algal sources must be carefully examined due to the numerous drawbacks and difficulties of fish oils and the lack of DHA and EPA in plant sources.This review focuses on the current state of omega-3 PUFA(polyunsaturated fatty acids)production,sources,and market demand to provide an overview of sources that are being explored for sustainability as well as current and anticipated market trends in the omega-3 industry.This will make it possible for them to be produced on a wide scale for the benefit of human health.展开更多
Saccharomyces cerevisiae,a common eukaryotic model microorganism that is generally recognized as safe,is widely employed for the heterologous expression of edible and therapeutic proteins.Promoters are crucial compone...Saccharomyces cerevisiae,a common eukaryotic model microorganism that is generally recognized as safe,is widely employed for the heterologous expression of edible and therapeutic proteins.Promoters are crucial components of protein expression systems and have been extensively studied.In this study,we characterized 93 endogenous promoters using a fluorescence characterization system with a high signal-to-noise ratio.The core promoter sequences of strong constitutive promoters were concatenated with different upstream activating sequences(UASs),ultimately resulting in a set of short constitutive promoters exhibiting 30%higher intensity than that of the commonly used strong constitutive promoter P_(TDH3).Similarly,a set of short inducible promoters with 20%higher intensity than that of the widely used inducible promoter PGAL1 was obtained by linking the core promoter sequences of strong inducible promoters with UAS_(GAL1).These short promoters were used to optimize ovalbumin expression.In conclusion,this study achieved shorter promoters with higher strength compared to that of the commonly used constitutive and inducible promoters in S.cerevisiae,thus laying the foundation for the rational design and simplification of the expression system.展开更多
Pinene is an active natural monoterpene from plants and has important applications in favorings,fragrances,and pesticides.Especially,pinene dimers are regarded as renewable fuels with high density.However,the microbia...Pinene is an active natural monoterpene from plants and has important applications in favorings,fragrances,and pesticides.Especially,pinene dimers are regarded as renewable fuels with high density.However,the microbial pinene production was limited by the low activity pinene synthase.In this study,the pinene synthase activity was improved by fusion linker optimization and chaperon coexpression.To construct the pinene pathway in Saccharomyces cerevisiae,YPL062W gene was deleted to increase the MVA pathway precursor acetyl-CoA.Truncated 3-hydroxyl-3-methylglutaryl-CoA reductase(tHMG1),isopentenyl-diphosphate isomerase(IDI1),and farnesyl diphosphate synthase mutant(ERG20F96W−N127W)were then integrated to improve the GPP pool.Pinene synthase tPt1 was expressed in the constructed engineered yeast,and the titer of pinene reached 0.166 mg/L.GPP is the direct precursor of pinene,ERG20ww and tPt1 were fused by diferent linkers and orders to improve the accessibility of GPP.Pinene titer reached 9.94 mg/L by fusion these proteins in the order of ERG20ww and tPt1 and with a fexible linker(G)8.After that,several chaperons were coexpressed and the chaperon Sil1p improved the pinene titer to 10.2 mg/L with a yield of 1.63 mg/L·OD600.The results presented here provide novel information on the applications of protein fusion and protein chaperons in microbial pinene production.展开更多
Introduction Probiotic foods,generally dairy-based,aren’t widely affordable in low-income countries.So it’s necessary to suggest suitable and accessible matrices for delivering probiotics.Objectives This study aimed...Introduction Probiotic foods,generally dairy-based,aren’t widely affordable in low-income countries.So it’s necessary to suggest suitable and accessible matrices for delivering probiotics.Objectives This study aimed to assess the probiotic traits of Lactiplantibacillus plantarum LO3 and its use in the development of a golden apple-based non-dairy probiotic beverage.Methods To this end,the probiotic and safety properties of Lact.plantarum LO3 were evaluated.Then,Lact.plantarum LO3 suspension was added to GaJ(≈log 7.67 cfu)and stored at 4 and 30℃.During storage,the proximate composition,the DPPH°activity as well as a sensory evaluation of the juice were performed.Results As a result,Lact.plantarum LO3 has excellent viability(˃97%)in gastric and intestinal juices respectively,after 2 and 4 h.As for adhesive properties,the highest co-aggregations were recorded against Escherichia coli(23.43%)and Vibrio parahaemolyticus(22.05%).In the GaJ,except day 21,Lact.plantarum LO3 load was significantly(p˂0.05)higher than the initial load.Ascorbic acid content decreased over time,with minima recorded on day 30(22.41 and 25.00 mg/100 ml)at 30 and 4℃respectively.Furthermore,the highest DPPH°activities(EC50)were 90.05 and 94.56μg/ml at 4 and 30℃respectively.Carbohydrates and fibre contents decreased significantly(p˂0.05)with storage temperature.In terms of sensory attributes,Lact.plantarum LO3 had a positive effect on odour at 30℃,while colour was better preserved at 4℃.Conclusions This makes golden apple juice a suitable matrix for carrying the probiotic strain Lact.plantarum LO3 for consumers from the whole spectrum of social classes.展开更多
Vibrio harveyi is a Gram-negative,rod-shaped,polar flagellate,facultatively anaerobic,halophilic,bioluminescent marine bacteria that belongs to the family of Vibrionaceae,class,Gammaproteobacteria.This pathogenic orga...Vibrio harveyi is a Gram-negative,rod-shaped,polar flagellate,facultatively anaerobic,halophilic,bioluminescent marine bacteria that belongs to the family of Vibrionaceae,class,Gammaproteobacteria.This pathogenic organism is responsible for various diseases of vertebrates and invertebrates in marine habitats,including shrimp aquaculture.Various symptoms like lesions,gastroenteritis,skin ulcers,eye lesions,and tail rot have been observed due to V.harveyi infection.The pathogenic-ity mechanism of V.harveyi involves endotoxin lipopolysaccharide,extracellular proteases,and bacteriophage interaction.Hemolysin genes encoded extracellular hemolysin-like phospholipase B toxin could inactivate fish species via the caspase inactivation pathway,ultimately leading to apoptosis.In addition,VBNC(viable but nonculturable)cells are another basis of vibriosis outbreaks in the shrimp aquaculture sector.The extensive amount of antibiotic use promotes the generation of multidrug-resistant strains.Therefore,as an alternative strategy to combat V.harveyi infection,bacteriophages are utilized as a biocontrol agent.However,there is a lack of research on the immobilization and development of encapsulation strategies of V.harveyi-infecting bacteriophages which need to be studied further.In conclusion,the pathogenicity of V.harveyi and its biocontrol by bacteriophages has been documented in this review.展开更多
8-Prenylnaringenin(8-PN)is a valuable medical phytoestrogen,which is a precursor to many prenylated flavonoids.How-ever,the availability of 8-PN is limited by inefficient prenyltransferases(PTs)and inadequate substrat...8-Prenylnaringenin(8-PN)is a valuable medical phytoestrogen,which is a precursor to many prenylated flavonoids.How-ever,the availability of 8-PN is limited by inefficient prenyltransferases(PTs)and inadequate substrate precursor levels in microbial chassis.First,six PTs from different sources and their truncated cognates were expressed in a(2S)-naringenin producing strain.Only SfN8DT-1 derived from Sophora flavescens and its truncated cognate,tSfN8DT-1,could synthe-size 8-PN.Second,tSfN8DT-1 was engineered by multiple sequence alignment and a mutant tSfN8DT-1^(Q12E)with greater catalytic activity was obtained.Third,key genes,tHMGR and IDI1,of the mevalonate(MVA)pathway were overexpressed using a copy number combinatorial strategy,which greatly improved 8-PN titer by 368.75%.Fourth,a predicted structure of tSfN8DT-1^(Q12E)was used for molecular docking and virtual saturation mutagenesis.Two key residues,P229 and N305,were identified and saturation mutagenesis on these two sites resulted in an improved mutant N305M.The best-performing mutant,tSfN8DT-1^(Q12EN305M),produced 49.35±0.05 mg/L(5.57±0.01 mg/g DCW)8-PN in a shaking flask.Finally,101.40±2.55 mg/L of 8-PN was obtained in a 5-L bioreactor,which is the greatest titer reported to date for 8-PN.This study combined metabolic engineering and protein engineering methods to enhance precursor supplements and improve the catalytic ability of SfN8DT-1.The production of 8-PN in Saccharomyces cerevisiae was greatly increased through these methods,which may provide a feasible strategy for the biosynthesis of prenylated flavonoids.展开更多
基金supported by the National Science and Technology Council(NSTC)project,Taiwan(Ref.No.112-2222-E-992-005).
文摘The escalating global challenges of food security,waste management,and environmental sustainability have necessitated the application of novel green approaches to utilize agro-industrial food waste as a valuable bioresource.Enzymatic conversion of food waste into high-value bioproducts emerges as one of the promising solutions to address these issues.The current review explores the critical role of enzymes in facilitating the conversion of diverse agro-industrial residues,including those from plants and animals,into biochemicals and functional ingredients.The current review evaluates the environmental and economic benefits of enzyme-mediated bioconversion processes,underlining the circular economy paradigm,which prioritizes resource efficiency and waste minimization.The enzyme production from diverse plant and animal-based food wastes as raw materials has been highlighted beside the description of different bioproducts from food waste using enzymes and the integration of enzymatic bioprocessing.The economic analysis and case studies of the enzyme-mediated processes for biochemical production from food waste have also been emphasized.By harnessing the synergistic potential of enzymes and circular economy principles,the bioconversion of agro-industrial food waste into novel bioproducts presents a viable pathway toward sustainable resource utilization and a circular bioeconomy.
基金This work was supported by the National Key Research and Development Program of China(2018YFA0900300)the National Natural Science Foundation of China(31870066,21778024)+1 种基金National First-Class Discipline Program of Light Industry Technology and Engineering(LITE2018-06)the Program of Introducing Talents of Discipline to Universities(111-2-06).
文摘Prodigiosin is a secondary metabolite mainly produced at 30°C in Serratia marcescens,but it can hardly be synthetized at 37°C or higher.In this study,we provide insight into the metabolic regulation of prodigiosin synthesis in response to temperature through transcriptome sequencing.The analysis of the function of differentially expressed genes suggested that temperature resulted in significant alteration of the metabolic pathways between 30 and 37°C.Specifically,30°C favored transcriptional expression of the pig gene cluster.At the same time,the carbon flux was redistributed to pathways of pyruvate,proline,serine,especially homoserine,cystathionine,homocysteine,methionine,and s-adenosylmethionine metabolism,all involved in prodigiosin biosynthesis,and was finally increased towards the prodigiosin synthesis pathway in S.marcescens at 30°C.Interestingly,results further confirmed increased transcriptional level of five regulators(LuxS,RpoS,Hfq,EepR,CRP),and decreased content of hexS through qPCR.Finally,successful co-overexpression of mmuM and metK,related to homocysteine,methionine,and s-adenosylmethionine metabolism,in the chromosome of JNB5-1(JNB5-1/MK)resulted in increased prodigiosin titer up to 7.57 g/L in JNB5-1/MK at 30°C,which was 41.2%higher than that in JNB5-1.Our transcriptome analysis provides further insight into the strain’s response to temperature changes at the transcription level,which is of great significance for improving the production of prodigiosin.
文摘The aim of this work was to study the efficiency of native lignocellulolytic enzymes obtained from isolated bacteria towards enhanced bioethanol production from lignocellulosic biomass.Maximum cellulose(199.33±0.2 mg/g)and hemicellulose(62.21±0.22 mg/g)content was measured from rice straw in alkali condition compared to acid and biological pretreatment,while significant lignin removal has been observed in biological pretreatment.Saccharification of rice straw using isolated cellulase–xylanase enzymes exhibited 60.33%production of total reducing sugar obtained by commercial cellulase–xylanase cocktail.Maximum glucose,xylose,and total reducing sugar yield of 309±0.32,190.7±0.42,and 499.7±0.37 mg/g,respec-tively,at 37.5℃,pH-7,rice straw concentration of 2.5 g/100 mL,enzyme loading 175μl,and incubation period 42 h by com-mercial cellulase–xylanase enzyme mediated hydrolysis.While in case of using the native cellulase–xylanase cocktail from the isolated bacterial strains,highest yields of glucose,xylose and total reducing sugar production was 253.52±0.56 mg/g,47.94±0.78 mg/g,and 301.46±0.67 mg/g,respectively.While applying the isolated enzymes on alkali-pretreated rice straw,bioethanol concentration of around 32.57±0.25 g/L was recorded after the simultaneous saccharification and fermentation by Saccharomyces cerevisiae.The above mentioned bioethanol concentration was obtained at a process parameter of temperature 35℃,incubation time 58 h,and pH 5.5 for isolated cellulase–xylanase enzymes.A maximum bioethanol concentration using isolated cellulase–xylanase enzymes was nearly 93.89%of bioethanol concentration(34.69±0.28 g/L)obtained using commercial cellulase–xylanase.The present study interpreted that the cutting-edge approach for the native enzymes along with metabolic engineering of the isolated bacteria could be promising towards enhanced bioethanol production.
文摘White biotechnology uses enzymes and microorganisms to produce value-added chemicals from renewable sources.White biotechnology provides valuable components for the food,pharmaceutical,agricultural sectors as well as other industries.Metabolic diversity in fungi,yeast,and bacteria can be exploited to produce food additives and other industrial products.This is an interesting topic for those interested in screening and metabolic testing of microorganisms,industrial biotechnology,fermentation technology,and the biological products research community.The use of microbial-derived compounds has a long history in the food industry,and compounds such as flavorings,essential amino acids,poly-unsaturated fatty acids,organic acids,gelling,etc.can be obtained from microbial sources.Also,the role of microbes in human health and well-being cannot be ignored.Microbes produce primary metabolites such as vitamins,nucleotides,and amino acids,as well as secondary metabolites.These secondary metabolites are used to make many drugs.In agriculture,microbes are also used to make fertilizers and biological pesticides.This paper reviews the types of bio-products obtained through biotechnology and the barriers and challenges of white biotechnology.
文摘In recent times,the microalga Chlorella vulgaris has attracted significant attention due to its multifaceted applications in diverse disciplines.Nonetheless,discrepancies in growth rates and biomass yield are observed across freshwater and saline environments.This research was designed to elucidate the impacts of varying concentrations ofNaHCO_(3),NPK fertilizer,and NaCl on the proliferation of Chlorella vulgaris cultivated in 288L plastic bottle bioreactors,ensuring optimal light exposure and aeration for algal propagation.Biomass quantifications were executed tri-weekly,utilizing metrics such as optical density(OD)and biomass concentration(mg/L).Post a 30-day cultivation period,the findings revealed that optimal biomass was attained with an augmentation of 30 mg/LNaHCO_(3) and 100 mg/L NPK.Remarkably,the alga manifested resilience to escalating salinity levels,recording a peak biomass of 1036 mg/L upon the introduction of 20 g/L NaCl.Moreover,the research underscored a robust correlation between optical density(OD)and biomass concentration(mg/L)amidst diverse salinity regimes,underscoring the criticality of these parameters in the proliferation of Chlorella vulgaris.
基金supported by the National Key Research and Development Program of China(2021YFC2100900).
文摘Escherichia coli contains 12 chaperone-usher operons,including 64 genes,used for biosynthesis and assembly of various fimbriae which consume a lot of energy and material.In this study,each of the 12 operons was deleted in an L-threonine-producing E.coli strain TWF001,and the resulting 12 deletion mutants produced more L-threonine than TWF001 after 16 or 24 h cultivation.Therefore,the 12 chaperone-usher operons were deleted in different combinations,resulting in 11 strain mutants which lack at least 2 operons.The cell growth and L-threonine production of these 11 mutants were determined.Among these 11 mutants,TWK021 in which 10 chaperone-usher operons were deleted,showed the highest L-threonine production.TWK021 produced 15.75 g L-threonine from 40 g glucose after 36 h cultivation.The conversion rate of glucose to L-threonine reached 0.394 g/g in TWK021,which is 32.2%higher than the control strain TWF001.These results suggest that the fimbria lacking E.coli TWK021 is a good host for efficient production of L-threonine.
基金This work was financially supported by the National Key Research and Development Program of China(2018YFA0900300)the National Natural science foundation of China(32171421).
文摘The ribosome-binding site(RBS)in the 5′untranslated region is recognized by 16S rRNA to start translation and is an essential element of the gene expression system.RBSs have been widely applied in regulating gene expression in various scenarios,including Gram-negative or Gram-positive bacteria.Here,we first rationally designed and constructed an RBS mutant library containing 66 RBSs.The strength of these RBSs in E.coli and C.glutamicum was characterized individually.The RBS strength spanned about 200 and 15 times in the two species,respectively.The strength of RBSs in C.glutamicum was generally lower than that of in E.coli.A total of 18 RBSs showed similar strength(within twofold differences)between the species in our study,and the correlation analysis of the strength of RBSs between E.coli and C.glutamicum(R^(2)=0.7483)revealed that these RBSs can be used across species.The sequence analysis revealed that the RBS region with two Ts stated was beneficial for RBS to function cross-species.The RBS characterized here can be used to precisely regulate gene expression in both hosts,and the characteristics of cross-species RBSs provide basic information for RBS rational design.
文摘Wastewaters from various process industries,namely food and agricultural,sugar mill,brewery,milk,vegetable and fruit,and meat and fsheries processing industries and their wastewater efuents contain nutrients,organic matter,inorganic,heavy metals,suspended solids,and pathogens.The discharges of non-treated wastewater enter the nearby aquatic ecosystem(e.g.,lakes,rivers)and are a signifcant concern due to the presence of diferent nutrients,competing ions and C containing pollutants.It causes excessive growth of algae,loss of habitat/species,and other negative impacts on human health/environment.In the present review,diferent treatment approaches have been discussed in utilizing these nutrients to synthesize value-added products such as biopolymer,biofuel,pigment,organic acid,or enzymes.These biopolymers can be used to prepare various food products/packaging materials.Dextran,chitosan,carrageenan,alginate,and pectin are good examples of non-food biopolymers.Besides these products,poly-β-hydroxybutyrate(PHB)synthesis from wastewater nutrients is reported as a new source of bio-nanocomposite materials/biopolymer-based coatings.In this review,the diferent treatment approaches are discussed,which are being used worldwide for the removal/recovery of nutrients,toxic pollutants,and the potential resource recovery of value-added products from wastewater.
基金the Science and Engineering Research Board(EEQ/2020/000095),Government of India,for their financial assistance.
文摘“In silico organisms”are computational genome-scale metabolic models used in systems and synthetic biology developed by constraint-based metabolic simulations using multi-omics and phenotypic data.The quality of these models is hidden because of the limited availability of genomic information and genome-scale metabolic reconstruction methods.In this review,237 manually curated genome-scale models for various organisms with industrial and clinical significance were comprehensively reviewed,and their modelling information was tabulated based on literature.This review provides a comprehensive summary of potential applications of systems biology in biotechnology and biomedical research.Their broad applicability has been explored in the process of model improvement and design of experiments in metabolic design and drug development.This review summarizes their recent advances,challenges,and practical applications in Gram-negative bacteria,Gram-positive bacteria,archaea,fungi,algae,plants,and animals.Genome-scale models of microbes have been reviewed to address their various applications in metabolic systems engineering,strain optimization,bioremediation,biomanufacturing,and personalized systems medicine.Several models have been explored to understand the molecular mechanisms underlying pathogenesis,virulence,host-microbe interactions,and metabolic crosstalk.This review provides an overview of the current knowledge on human metabolic reconstructions and their important roles in human,microbiota-related,and complex metabolic disorders.Genome-scale models of human and animal metals offer ethical alternatives to the traditional animal testing methods.Current progress in systems biology research will lead to the development of indispensable databases,computational tools,and analytical platforms.This will strengthen data-driven discovery and facilitate integration of biological information into living systems.
基金financially supported by the National Natural Science Foundation of China(32370066)the Fundamental Research Funds for the Central Universities(JUSRP622003)+1 种基金National First-class Discipline Program of Light Industry Technology and Engineering(QGJC20230202)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_2487).
文摘UDP-sugars,as active forms of monosaccharides,play integral roles in glycosylation and biosynthesis of polysaccharides.Although enzymatic catalysis has achieved great process,the comparatively low productivity and the time-consuming enzyme purification processes restricted its practical applications.Here,we developed two CipA-dependent enzyme immobiliza-tion systems for synthesis of UDP-GlcNAc and UDP-GlcA.Initially,we selected and identified the enzyme combinations of PpAmgK and SeGlmU for UDP-GlcNAc(3.19 mM)synthesis,and AtGlcAK and BlUSP for UDP-GlcA(1.83 mM)synthesis.After optimizing the molar ratios of substrates,the production of UDP-GlcNAc and UDP-GlcA increased to 17.33 mM and 9.03 mM when setting UTP:GlcNAc:ATP and UTP:GlcA:ATP as 1:1:1 and 1:2:1,respectively.Then,the polyphosphokinase SePPK for recycling ADP and PPi was introduced,resulting in a significant increase in UDP-GlcNAc(29.33 mM)and UDP-GlcA(20.87 mM).Eventually,the CipA-based immobilization systems were developed for repetitive catalysis.The combinations of PSK-(G_(4)S)_(3)-CipA and CipA-(G_(4)S)_(3)-ABK yielded the comparable productions of UDP-GlcNAc(28.66 mM,17.40 g/L)and UDP-GlcA(20.34 mM,11.80 g/L)within 75 min.This study presents a convenient and reusable CipA-based enzyme immobilization system for synthesis of UDP-sugars,showing great potential for enzymatic production of UDP-GlcNAc and UDP-GlcA.
基金The authors would like to thank Dr.Rajeev K.Sukumaran and his group,Microbial Process and Technology Division,CSIR-National Institute for Interdisciplinary Science and Technology,for their extensive help with the characterization of biomass and the Director,IBSD,for his motivation and support(IBSD Manuscript No.IBSD/2020/01/061).
文摘Due to abundant availability,biofuel production from bamboo residues is gaining popularity.Bamboo biomass and its residues are widely available in the north-eastern part of India,which can be sustainably exploited for green energy production.The aim of the present study was to evaluate the pretreatments of dewaxed bamboo residues with dilute alkali(NaOH),and dilute acid,and the effect of pretreatment on biomass hydrolysis was performed with a commercial enzyme(Zytex).Results showed that maximum fermentable sugars were 490 mg/g obtained from 10%biomass with 0.6%(w/v)of alkali,and acid pretreated biomass produced 320 mg/g of sugars from 2%(w/v)acid with 10%biomass.Changes in biomass structure during the pretreatment process are correlated with FTIR,SEM,and component analysis for lignin,cellulose,and hemicelluloses.Fermentation studies of the hydrolysate showed that the yield of ethanol was 77%of the theoretical maximum at 36 h.Results indicate the scope of utilization of bamboo residues as substrates for biofuels,and alkaline pretreatment is an effective pretreatment process for bioethanol production.
基金supported by DST(Department of Science and Technology)—FIST(Fund for Improvement of S&T)India.
文摘Degradation of pendimethalin by microorganisms is an approach seeking more attention nowadays.This study aims to isolate a new strain of Planococcus,which is capable of degrading pendimethalin from the soil in rice field.Identification of this coccus bacterium was done by phylogenetic analysis of 16S rRNA gene sequence.Strain PD6 was found to grow potentially on pendimethalin supplemented minimal salt medium and degraded 50 mg L^(-1) pendimethalin in monosubstrate system.Fourier transform infrared(FTIR)spectroscopy was performed to check degradation of pendimethalin by Planococcus,which was demonstrated by changing chemical bonding and stretching patterns.This study was further extended to predict possible first enzyme of pendimethalin-degradation pathway.Molecular docking was performed to check efficient binding of dehydrogenase with pendimethalin.This strain of Planococcus degraded pendimethalin with relatively high efficiency in minimal salt media and is presented as another possible bacterium other than species of Bacillus and Pseudomonas which are already demonstrated as potential in vitro pendimethalin-degrading bacteria.Moreover,docking reveals that dehydrogenases having more chance to prove as first regulatory enzyme of pendimethalin-degradation pathway.
文摘In this study,a total of 1125 actinobacteria were isolated from the selected mangrove species:Avicennia marina,Rhizopora mucronata and Ceriops tagal from three study stations viz.,Minnie Bay,Carbyn’s Cove and Burmanallah.Among these three stations,the highest number of actinobacteria was recorded in Carbyn’s Cove(64.97%),followed by(25.51%)at Burmanallah and the minimum of(9.51%)was recorded in Minnie Bay.Maximum number of actinobacteria was recorded from Ceriops tagal(40.44%)than the other selected mangrove species Avicennia marina(34.13%)and Rhizopora mucronata(25.42%).Among the 1,125 mangrove-associated actinobacteria,103 morphologically different isolates from the Minnie Bay station was selected for the further characterization studies.In antibacterial assay,30.11%of the isolates revealed inhibitory activ-ity against all tested clinical pathogens and 65%isolates displayed inhibitory activity against minimum of 04 tested clinical pathogens.Growth survival studies of the actinobacterial isolates also accomplished to withstand in varied NaCl and pH levels.Of 103 isolates,all were found to synthesize gelatinase enzyme,73 isolates demonstrated amylolytic activity,38 isolates exhibited proteolytic and 63 isolates displayed urease activity.Interestingly,56 isolates exhibited excellent DNase activity and 71 isolates revealed positive for l-asparaginase production.To our recognition,11 isolates exhibited constructive results in the production of 06 extracellular enzymes of industrial importance.Of 103 isolates,48 isolates were confirmed by molecular level identification.Based on the phylogenetic analysis,the isolates were categorized under the genera:Strep-tomyces,Nocardiopsis,Salinispora and Actinomadura.
基金Open access funding provided by University Of Stavanger.Funding information that explains whether and by whom the research was supported.
文摘Bioelectrochemical systems(BESs)are a new and emerging technology in the field of fermentation technology.Electrical energy was provided externally to the microbial electrolysis cells(MECs)to generate hydrogen or value-added chemicals,including caustic,formic acid,acetic acid,and peroxide.Also,BES was designed to recover nutrients,metals or remove recalcitrant compounds.The variety of naturally existing microorganisms and enzymes act as a biocatalyst to induce poten-tial differences amid the electrodes.BESs can be performed with non-catalyzed electrodes(both anode and cathode)under favorable circumstances,unlike conventional fuel cells.In recent years,value-added chemical producing microbial electrosyn-thesis(MES)technology has intensely broadened the prospect for BES.An additional strategy includes the introduction of innovative technologies that help with the manufacturing of alternative materials for electrode preparation,ion-exchange membranes,and pioneering designs.Because of this,BES is emerging as a promising technology.This article deliberates recent signs of progress in BESs so far,focusing on their diverse applications beyond electricity generation and resulting performance.
文摘Omega-3 fatty acids are polyunsaturated fatty acids that are vital for human food consumption and metabolism.Eicosapen-taenoic acid(EPA)and docosahexaenoic acid(DHA),two long-chain polyunsaturated fatty acids(LC-PUFAs),are primarily obtained from diatoms in the oceanic food web.Though microalgae are the main producers of EPA and DHA,but currently,only few algal strains are known to produce large levels of EPA and DHA.The demand for nutraceuticals has significantly increased because of people’s increased awareness and health consciousness.Due to foods being the concentrated supply of omega-3 PUFAs(polyunsaturated fatty acids),this has increased the demands on aquatic sources of n-3 PUFAs.Micro-algal sources must be carefully examined due to the numerous drawbacks and difficulties of fish oils and the lack of DHA and EPA in plant sources.This review focuses on the current state of omega-3 PUFA(polyunsaturated fatty acids)production,sources,and market demand to provide an overview of sources that are being explored for sustainability as well as current and anticipated market trends in the omega-3 industry.This will make it possible for them to be produced on a wide scale for the benefit of human health.
基金supported by the National Key Research and Development Program of China(2020YFA0908300)the National Natural Science Foundation of China(32101913,32222069)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(32021005).
文摘Saccharomyces cerevisiae,a common eukaryotic model microorganism that is generally recognized as safe,is widely employed for the heterologous expression of edible and therapeutic proteins.Promoters are crucial components of protein expression systems and have been extensively studied.In this study,we characterized 93 endogenous promoters using a fluorescence characterization system with a high signal-to-noise ratio.The core promoter sequences of strong constitutive promoters were concatenated with different upstream activating sequences(UASs),ultimately resulting in a set of short constitutive promoters exhibiting 30%higher intensity than that of the commonly used strong constitutive promoter P_(TDH3).Similarly,a set of short inducible promoters with 20%higher intensity than that of the widely used inducible promoter PGAL1 was obtained by linking the core promoter sequences of strong inducible promoters with UAS_(GAL1).These short promoters were used to optimize ovalbumin expression.In conclusion,this study achieved shorter promoters with higher strength compared to that of the commonly used constitutive and inducible promoters in S.cerevisiae,thus laying the foundation for the rational design and simplification of the expression system.
基金This work was supported by the National Natural Science Foundation of China(No.31970033).
文摘Pinene is an active natural monoterpene from plants and has important applications in favorings,fragrances,and pesticides.Especially,pinene dimers are regarded as renewable fuels with high density.However,the microbial pinene production was limited by the low activity pinene synthase.In this study,the pinene synthase activity was improved by fusion linker optimization and chaperon coexpression.To construct the pinene pathway in Saccharomyces cerevisiae,YPL062W gene was deleted to increase the MVA pathway precursor acetyl-CoA.Truncated 3-hydroxyl-3-methylglutaryl-CoA reductase(tHMG1),isopentenyl-diphosphate isomerase(IDI1),and farnesyl diphosphate synthase mutant(ERG20F96W−N127W)were then integrated to improve the GPP pool.Pinene synthase tPt1 was expressed in the constructed engineered yeast,and the titer of pinene reached 0.166 mg/L.GPP is the direct precursor of pinene,ERG20ww and tPt1 were fused by diferent linkers and orders to improve the accessibility of GPP.Pinene titer reached 9.94 mg/L by fusion these proteins in the order of ERG20ww and tPt1 and with a fexible linker(G)8.After that,several chaperons were coexpressed and the chaperon Sil1p improved the pinene titer to 10.2 mg/L with a yield of 1.63 mg/L·OD600.The results presented here provide novel information on the applications of protein fusion and protein chaperons in microbial pinene production.
文摘Introduction Probiotic foods,generally dairy-based,aren’t widely affordable in low-income countries.So it’s necessary to suggest suitable and accessible matrices for delivering probiotics.Objectives This study aimed to assess the probiotic traits of Lactiplantibacillus plantarum LO3 and its use in the development of a golden apple-based non-dairy probiotic beverage.Methods To this end,the probiotic and safety properties of Lact.plantarum LO3 were evaluated.Then,Lact.plantarum LO3 suspension was added to GaJ(≈log 7.67 cfu)and stored at 4 and 30℃.During storage,the proximate composition,the DPPH°activity as well as a sensory evaluation of the juice were performed.Results As a result,Lact.plantarum LO3 has excellent viability(˃97%)in gastric and intestinal juices respectively,after 2 and 4 h.As for adhesive properties,the highest co-aggregations were recorded against Escherichia coli(23.43%)and Vibrio parahaemolyticus(22.05%).In the GaJ,except day 21,Lact.plantarum LO3 load was significantly(p˂0.05)higher than the initial load.Ascorbic acid content decreased over time,with minima recorded on day 30(22.41 and 25.00 mg/100 ml)at 30 and 4℃respectively.Furthermore,the highest DPPH°activities(EC50)were 90.05 and 94.56μg/ml at 4 and 30℃respectively.Carbohydrates and fibre contents decreased significantly(p˂0.05)with storage temperature.In terms of sensory attributes,Lact.plantarum LO3 had a positive effect on odour at 30℃,while colour was better preserved at 4℃.Conclusions This makes golden apple juice a suitable matrix for carrying the probiotic strain Lact.plantarum LO3 for consumers from the whole spectrum of social classes.
基金The authors are grateful to Science and Engineering Research Board(SERB),a statutory body of the Department of Science&Technology,Govt.of India(Sanction Order No.CRG/2019/001750 dated 14th January,2020)for financial assistance.
文摘Vibrio harveyi is a Gram-negative,rod-shaped,polar flagellate,facultatively anaerobic,halophilic,bioluminescent marine bacteria that belongs to the family of Vibrionaceae,class,Gammaproteobacteria.This pathogenic organism is responsible for various diseases of vertebrates and invertebrates in marine habitats,including shrimp aquaculture.Various symptoms like lesions,gastroenteritis,skin ulcers,eye lesions,and tail rot have been observed due to V.harveyi infection.The pathogenic-ity mechanism of V.harveyi involves endotoxin lipopolysaccharide,extracellular proteases,and bacteriophage interaction.Hemolysin genes encoded extracellular hemolysin-like phospholipase B toxin could inactivate fish species via the caspase inactivation pathway,ultimately leading to apoptosis.In addition,VBNC(viable but nonculturable)cells are another basis of vibriosis outbreaks in the shrimp aquaculture sector.The extensive amount of antibiotic use promotes the generation of multidrug-resistant strains.Therefore,as an alternative strategy to combat V.harveyi infection,bacteriophages are utilized as a biocontrol agent.However,there is a lack of research on the immobilization and development of encapsulation strategies of V.harveyi-infecting bacteriophages which need to be studied further.In conclusion,the pathogenicity of V.harveyi and its biocontrol by bacteriophages has been documented in this review.
基金supported by the National Key Research and Development Program of China(2019YFA0904800)the National Science Fund for Excellent Young Scholars(21822806)the National Natural Science Foundation of China(21908078).
文摘8-Prenylnaringenin(8-PN)is a valuable medical phytoestrogen,which is a precursor to many prenylated flavonoids.How-ever,the availability of 8-PN is limited by inefficient prenyltransferases(PTs)and inadequate substrate precursor levels in microbial chassis.First,six PTs from different sources and their truncated cognates were expressed in a(2S)-naringenin producing strain.Only SfN8DT-1 derived from Sophora flavescens and its truncated cognate,tSfN8DT-1,could synthe-size 8-PN.Second,tSfN8DT-1 was engineered by multiple sequence alignment and a mutant tSfN8DT-1^(Q12E)with greater catalytic activity was obtained.Third,key genes,tHMGR and IDI1,of the mevalonate(MVA)pathway were overexpressed using a copy number combinatorial strategy,which greatly improved 8-PN titer by 368.75%.Fourth,a predicted structure of tSfN8DT-1^(Q12E)was used for molecular docking and virtual saturation mutagenesis.Two key residues,P229 and N305,were identified and saturation mutagenesis on these two sites resulted in an improved mutant N305M.The best-performing mutant,tSfN8DT-1^(Q12EN305M),produced 49.35±0.05 mg/L(5.57±0.01 mg/g DCW)8-PN in a shaking flask.Finally,101.40±2.55 mg/L of 8-PN was obtained in a 5-L bioreactor,which is the greatest titer reported to date for 8-PN.This study combined metabolic engineering and protein engineering methods to enhance precursor supplements and improve the catalytic ability of SfN8DT-1.The production of 8-PN in Saccharomyces cerevisiae was greatly increased through these methods,which may provide a feasible strategy for the biosynthesis of prenylated flavonoids.
