5-Aminolevulinic acid （ALA） is a common precursor for tetrapyrrole compounds in all kinds of organ isms and has wide applications in agriculture and medicines. In this study, a new strategy, i.e. short-term dissolve...5-Aminolevulinic acid （ALA） is a common precursor for tetrapyrrole compounds in all kinds of organ isms and has wide applications in agriculture and medicines. In this study, a new strategy, i.e. short-term dissolved oxygen （DO） shock during aerobic fermentation, was introduced to produce 5-aminolevulinic acid with a recombi-nant E. coli. Effects of duration time of DO shock operation on plasmid concentration, intracellular ALA synthase （ALAS） activity and ALA production were investigated in Erlenmeyer shake flasks. The results indicated that both ALAS activity and ALA yield were enhanced in an anaerobic operation of 45 rain in the early exponential phase during fermentation, while they decreased when the anaerobic operation time was further increased to 60 rain. The DO shock protocol was confirmed with the fed-batch fermentation in a 15 L fermenter and the ALA production achieved 9.4 g.L-1 （72 mmol.L-1）, which is the highest yield in the fermentation broth reported up to now.展开更多
L-(+)-Lactic acid production from corncob hydrolysate as a cheap carbohydrate source by fed-batch fermentation of Rhizopus oryzaeHZS6 was studied. After 96 h of fermentation in a 5 L fermentor, the final concentration...L-(+)-Lactic acid production from corncob hydrolysate as a cheap carbohydrate source by fed-batch fermentation of Rhizopus oryzaeHZS6 was studied. After 96 h of fermentation in a 5 L fermentor, the final concentration of ammonium L-(+)-lactate, average productivity(based on initial xylose concentration) and maximum dry cell weight were 132.4 g/L, 1.38 g/(L·h), and 8.9 g/L respectively. The optical purity of L-(+)-lactate was 98.8%.展开更多
An iterative optimization strategy for fed-batch fermentation process is presented by combining a run-to-run optimization with swarm energy conservation particle swarm optimization (SEC-PSO). SEC-PSO, which is designe...An iterative optimization strategy for fed-batch fermentation process is presented by combining a run-to-run optimization with swarm energy conservation particle swarm optimization (SEC-PSO). SEC-PSO, which is designed with the concept of energy conservation, can solve the problem of premature convergence frequently appeared in standard PSO algorithm by partitioning its population into several sub-swarms according to the energy of the swarm and is used in the optimization strategy for parameter identification and operation condition optimization. The run-to-run optimization exploits the repetitive nature of fed-batch processes in order to deal with the optimal problems of fed-batch fermentation process with inaccurate process model and unsteady process state. The kinetic model parameters, used in the operation condition optimization of the next run, are adjusted by calculating time-series data obtained from real fed-batch process in the run-to-run optimization. The simulation results show that the strategy can adjust its kinetic model dynamically and overcome the instability of fed-batch process effectively. Run-to-run strategy with SEC-PSO provides an effective method for optimization of fed-batch fermentation process.展开更多
Bioreactor operation requires continuous monitoring of fermentation parameters and real-time control over bioreactor devices. Remote monitoring and control of the bioreactor＇s computer via the Internet avoids the nec...Bioreactor operation requires continuous monitoring of fermentation parameters and real-time control over bioreactor devices. Remote monitoring and control of the bioreactor＇s computer via the Internet avoids the necessity of personnel being continually onsite during operation. A two liter Sartorius-stedim Biostat~ A Plus fermentation system was networked and interfaced with the commercial software from GoToMyPC to allow remote control of the fermentation system utilizing the internet. The fermentation vessel was equipped with hardware calibrated for monitoring and controlling culture parameters during experimentations. The uniform resource locator controlled night-vision web camera allowed continuous monitoring of the glass fermentation vessel during the day and at night. The main window screen of the laboratory computer can be securely accessed from any portable device （i.e. laptop） capable of establishing an Internet connection and executing the commercial software from GoToMyPC. The secured internet protocol address, provided by GoToMyPC, assures that the system can only be controlled by authorized users who have been given access to the account. This interface permits the remote control of the Biostat A Plus fermentation system and possibly other automated or potentially automated culturing systems at the convenience of the user（s）.展开更多
An on-line scheduling algorithm to maximize gross profit of penicillin fed-batch fermentation is proposed. According to the on-line classification method, fed-batch fermentation batches are classified into three categ...An on-line scheduling algorithm to maximize gross profit of penicillin fed-batch fermentation is proposed. According to the on-line classification method, fed-batch fermentation batches are classified into three categories. Using the scheduling strategy, the optimal termination sequence of batches is obtained. Pseudo on-line simulations for testing the proposed algorithm with the data from industrial scale penicillin fermentation are carried out.展开更多
[Background]Surfactin is a biosurfactant with remarkable surface/interfacial activity.Surfactin production suffers from high costs of carbon sources and severe foaming problem during fermentation.Unreasonable utilizat...[Background]Surfactin is a biosurfactant with remarkable surface/interfacial activity.Surfactin production suffers from high costs of carbon sources and severe foaming problem during fermentation.Unreasonable utilization of soybean residue(okara)can cause resource waste and environmental pollution.[Objective]To achieve sustainable production of surfactin and valueadded conversion of okara,we explored foam-free production of surfactin by Bacillus subtilis using okara as a low-cost substrate and evaluated its application prospects.[Methods]We evaluated and compared the feasibility of B.subtilis utilizing okara to synthesize surfactin through liquid and solid-state fermentation methods.Biosurfactants were extracted from solid-state culture via a weak alkaline water extraction method.The products were identified by HPLC-MS,and the physicochemical properties of the produced surfactin were analyzed.The solid-state medium for fermentation of okara was optimized by the response surface method.The viable count of B.subtilis in solid-state fermentation residue was determined by the plate colony counting method.[Results]The conversion rates of okara to surfactin were 0.6%−0.8%and 1.2%−1.5%in liquid and solid-state fermentation,respectively.Interestingly,solid-state fermentation of okara by B.subtilis achieved both high-yield and foam-free production of surfactin.Five surfactin homologues were produced from okara,mainly including surfactin-C13(34.16%),surfactin-C_(14)(23.95%),and surfactin-C_(15)(35.14%).The produced surfactin,with a critical micelle concentration of 35.0 mg/L,decreased water surface tension to(26.0±0.1)mN/m and emulsified crude oil with emulsifying activity index(EI24)(73.1±3.2)%.It was stable at 4−121℃,pH 5.0−11.0,and NaCl<150 g/L.Okara,NH_(4)Cl,and CaCl_(2)·2H_(2)O were significant components in the solid-state medium.The surfactin yield was increased by 52.1%through solid-state medium optimization.Adding wheat straw further enhanced surfactin production by improving aeration in the solid-state medium.B.subtilis AnPL-1 produced(263.2±7.8)mg surfactin in the optimized solid-state medium containing 14.8 g okara and 1.5 g wheat straw.The conversion rate of okara to surfactin was enhanced to 1.8%.In addition,the residue of solid-state fermentation was expected to be microbial fertilizer since it contained 4.27×10^(10)CFU/g of B.subtilis.[Conclusion]This study established a promising way for foam-free production of surfactin and value-added conversion of okara.展开更多
Pomegranate residues(PRs),namely pomegranate peels and seeds remaining after juice extraction,constitute a significant agro-industrial residue in Greece.Despite their ample content in carbon sources and bioactive comp...Pomegranate residues(PRs),namely pomegranate peels and seeds remaining after juice extraction,constitute a significant agro-industrial residue in Greece.Despite their ample content in carbon sources and bioactive compounds,PRs are largely unexploited,with their management being an increasing concern for the pome-granate processing industry.The objective of this study was the development and characterization of a bio-process aiming at the biotechnological valorization of PRs for ethanol production.Specifically,a stepwise investigation was conducted,including(i)the production and chemical characterization of extracts/hydrolysates from PRs using distinct pretreatments not involving organic solvents or enzymatic hydrolysis;(ii)the assessment of the exploitability of a selected hydrolysate as fermentation feedstock using Saccharomyces cerevisiae;and(iii)the advancement of the bioprocess through the joined utilization in the fermentation substrate of PRs and seeded raisins(SRs),another important agro-industrial residue in Greece.The finally developed substrate,comprising a mixture of PRs/SRs extracts at concentrations 60/40%v/v,was used in three fermentation trials,and the fermentation process was quantitatively described using the Aiba model.The developed bioprocess resulted in satisfactorily high bioethanol production with the maximum attained concentration being 50.0±0.6 g/L.The maximum specific growth rate(μ_(max))of S.cerevisiae was estimated to be 0.1351/h and the bioethanol yield(Y_(ps)),namely the amount of produced ethanol/amount of consumed reducing sugars,was estimated to be 0.423 g/g.Hence,PRs can be efficiently used in the development of a fermentation substrate for bioethanol production,providing an economic and environmentally sustainable alternative to conventional feedstocks.展开更多
Environment serves as the pivotal medium to produce fermented food,with fluctuations in environmental factors exerting a profound impact on the modulation of fermentation microbial communities.Such shifts are crucial ...Environment serves as the pivotal medium to produce fermented food,with fluctuations in environmental factors exerting a profound impact on the modulation of fermentation microbial communities.Such shifts are crucial for the distinctiveness of fermented food flavor and the variability in quality.Chinese liquor(Baijiu)is one of the typical representatives of spontaneous fermented food.In this review,the multifaceted relationship between regional environmental attributes and the fermentation dynamics of Baijiu was examined,with a spotlight on the strong-flavor,sauce-flavor,and light-flavor varieties.It reveals the influence of regional environmental factors and brewing environmental factors on microbial function and metabolism,which results in the formation of unique flavor characteristics of Baijiu.The 9 main factors affecting the microecology of Baijiu fermentation were further explored,including environmental sensitivity,microbial interactions,biogeographic patterns,and key abiotic factors such as temperature and humidity.Environmental factor management is crucial for controlling microbial community in fermentation.Intelligent detection of the fermentation system is combined with artificial intelligence to realize the digitalization of Baijiu fermentation,with a view to further studying the environmental mechanism or quantitative control relationship of natural fermentation,improving the environmental stability of natural fermentation,and promoting the mechanization and intelligence of fermentation production.展开更多
The variation in microbiota during pit fermentation is the main reason for the distinct characteristics of the 7 types of base Baijiu in jiang-flavor Baijiu(JFB)brewing.However,the specific structure,succession,and fu...The variation in microbiota during pit fermentation is the main reason for the distinct characteristics of the 7 types of base Baijiu in jiang-flavor Baijiu(JFB)brewing.However,the specific structure,succession,and functional differentiation of microbial communities across different fermentation rounds remain unclear.Therefore,this study compared the differences in microbiota structure,environmental factors driving community assembly,and functional differentiations throughout 1–7 rounds(JC1–JC7)of pit fermentation in JFB production.Results showed that Lactobacillus dominated all rounds and complied with declining relative abundance from rounds JC1–JC7.The mould composition was similar in JC3–JC5 while the yeast structure in JC4 was found intermediate between JC3 and JC5.LEf Se analysis unveiled aroma-producing microorganisms as prominent biomarkers in JC1,strong enzyme-producing attributes in JC2,JC6,and JC7 biomarkers,and an enzyme and aroma-producing focus with robust tolerance in JC3–JC5 biomarkers.Acidity mainly regulated the microbial community in the first 4 rounds,with nutrient limitation drove microbial succession from the fifth round onward.Functional predictions underscored enriched amino acid metabolism enzymes in JC6 and JC1,while carbohydrate degradation exhibited predominant enzymatic profiles in JC2,JC6,and JC7.This study laid a foundation for comprehending community composition,succession,and flavor regulatory mechanisms throughout JFB brewing.展开更多
Okara is produced in large quantities annually in China,but much of it is discarded due to its high content of indigestible dietary fiber(DF),contributing to significant environmental challenges.Recognizing the undere...Okara is produced in large quantities annually in China,but much of it is discarded due to its high content of indigestible dietary fiber(DF),contributing to significant environmental challenges.Recognizing the underexplored medicinal potential of DF,we developed an efficient fermentation method to enhance the bioavailability of okara fiber.In this study,Pediococcus acidilactici IFJ-1,which has strong enzymatic production capabilities and beneficial effects on gastrointestinal flora modulation,was selected to ferment okara.Results showed decreases in viscosity and particle size,optimized surface structure,improved thermal stability and hydration properties,and a significant increase in soluble DF content from 1.85%to 3.91%.To evaluate the physiological effects,hyperlipidemic mouse models were established and subjected to dietary interventions utilizing okara and fermented okara to measure changes in physicochemical parameters,gut microbiota composition,and lipid metabolism.The dietary intervention was effective,particularly in the fermented okara group,showing a 7.3%weight loss,improved blood lipids(triglycerides:‒39.8%,total cholesterol:‒12.8%,low-density lipoprotein cholesterol:‒34.2%,high-density lipoprotein cholesterol:+26.2%),and a 22.2%lower liver index.Gut microbiota analysis revealed that fermented okara positively modulated the microbial community by increasing the abundance of beneficial bacteria(e.g.,Bacteroidota)and reducing the abundance of obesity-associated bacteria(e.g.,Bacillota).Lipid metabolism profiling further demonstrated that fermented okara downregulated harmful lipids(e.g.,(O-acyl)-ω-hydroxy fatty acids,ceramides,and diacylglycerols)while upregulating beneficial phospholipids(e.g.,phosphatidylinositol,phosphatidylserine,phosphatidylethanolamine,lysophosphatidylinositol and lysophosphatidic acid).This study highlights a novel approach for enhancing DF utilization through fermentation,providing valuable insights into strategies for preventing obesity and metabolic diseases.展开更多
In the actual microbial fermentation process,excessive or insufficient substrate can produce inhibitory effects on cells growth.The artificial substrate feeding rules by past experiences have great blindness to keep s...In the actual microbial fermentation process,excessive or insufficient substrate can produce inhibitory effects on cells growth.The artificial substrate feeding rules by past experiences have great blindness to keep substrate concentration in a given appropriate range.This paper considers that alkali feed depends on pH value of the solution and glycerol feed depends on glycerol concentration of the solution in the uncoupled microbial fed-hatch fermentation process,and establishes a state-dependent switched system in which the flow rates of glycerol and alkali,the number of mode switches,the mode sequence and the switching times are prior unknown.To maximize the yield of target product 1,3-Propanediol(1,3-PD),we formulate a switching optimal control problem with the flow rates of glycerol and alkali,the number of mode switches,the mode sequence and the switching times as decision variables,which is a mixed-integer dynamic programming problem.For solving the mixed-integer dynamic programming problem,the control parametrization technique,the time scaling transformation and the embedded system technology are used to obtain an approximate parameter optimization problem.By using a parallel optimization algorithm,we obtain the optimal control strategies.Under the obtained optimal control strategies,the 1,3-PD yield at the terminal time is increased significantly compared with the previous results.展开更多
To investigate the in vitro digestion and fermentation properties of soybean oligosaccharides(SBOS)extracted from defatted soybean meal,the changes in monosaccharide composition and molecular mass were analyzed.Subseq...To investigate the in vitro digestion and fermentation properties of soybean oligosaccharides(SBOS)extracted from defatted soybean meal,the changes in monosaccharide composition and molecular mass were analyzed.Subsequently,the effect of SBOS on microbial community structure and metabolites was studied by 16S rRNA gene sequencing and untargeted metabolomics based on liquid chromatography-mass spectrometry.Results showed that SBOS was not easily enzymolyzed during simulated digestion and could reach the large intestine through the digestive system.The significant decrease in the molecular mass of SBOS after in vitro fermentation indicated its utilization by the gut microbiota,which increased the contents of short-chain fatty acids and lactic acid,thereby reducing the pH of the fermentation broth.Moreover,the core community was found to consist of Blautia,Lactobacillaceae,and Pediococcus.SBOS up-regulated beneficial differential metabolites such as myo-inositol,lactose,and glucose,which were closely related to galactose,amino sugar,and nucleotide sugar metabolism.This study will provide a reference for exploring the relationship between the gut microbiota and the metabolites of SBOS,and provide a basis for the development and application of SBOS as an ingredient for functional products.展开更多
In this paper,a novel fuzzy neural network model,in which an adjustable fuzzy sub-space was designed by uniform design,has been established and used in fed-batch yeast fermentationas an example.A brand-new optimizatio...In this paper,a novel fuzzy neural network model,in which an adjustable fuzzy sub-space was designed by uniform design,has been established and used in fed-batch yeast fermentationas an example.A brand-new optimization sub-network with special structure has been built andgenetic algorithm,guaranteeing the optimization in overall space,is introduced for the feed rateoptimization.On the basis of the model network,the optimal substrate concentration and theoptimal amount of fed-batch at different periods have been studied,aided with the optimizationnetwork and the genetic algorithm separately.The above results can be used as a basis for theestablishment of a fuzzy neural network controller.展开更多
Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship b...Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization,energy metabolism,and gut microbiota in growing pigs.Methods Thirty-six growing barrows(47.2±1.5 kg)were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3β-glucan-to-arabinoxylan ratios.In the experiment,nutrient utilization,energy metabolism,fecal microbial community,and production and absorption of short-chain fatty acid(SCFA)of pigs were investigated.In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig’s hindgut.Results The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber.In animal experiments,increasing the dietary apparent viscosity and theβ-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility(AID),apparent total tract digestibility(ATTD),and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter(P<0.05).In addition,increasing dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased gas exchange,heat production,and protein oxidation,and decreased energy deposition(P<0.05).The dietary apparent viscosity andβ-glucanto-arabinoxylan ratios had linear interaction effects on the digestible energy,metabolizable energy,retained energy(RE),and net energy(NE)of the diets(P<0.05).At the same time,the increase of dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased SCFA production and absorption(P<0.05).Increasing the dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria(P<0.05)and the relative abundance of beneficial bacteria.Furthermore,increasing the dietaryβ-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta(P<0.001).Finally,the prediction equations for RE and NE were established.Conclusion Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization,energy metabolism,and pig gut microbiota composition and metabolites.展开更多
Background Rumen microorganisms are key regulators of ruminant growth and production performance.Identifying probiotic candidates through microbial culturomics presents a promising strategy for improving ruminant prod...Background Rumen microorganisms are key regulators of ruminant growth and production performance.Identifying probiotic candidates through microbial culturomics presents a promising strategy for improving ruminant production performance.Our previous study identified significant differences in rumen microbial communities of Holstein calves with varying average daily gain(ADG).This study aims to identify a target strain based on the findings from multi-omics analysis and literature review,isolating and evaluating the target microbial strains from both the rumen and hindgut contents for their probiotic potential.Results Parabacteroides distasonis,a strain closely associated with ADG,was successfully isolated from calf rumen content cultured with Fastidious Anaerobe Agar(FAA)medium and named Parabacteroides distasonis F4.Wholegenome sequencing and pan-genome analysis showed that P.distasonis F4 possesses a core functional potential for carbohydrate and amino acid metabolism,with the ability to produce propionate,acetate,and lactate.The results of targeted and untargeted metabolomics further validated the organic acid production and metabolic pathways of P.distasonis F4.An in vitro simulated rumen fermentation test showed that supplementation with P.distasonis F4 significantly altered rumen microbial community structure and increased the molar proportions of propionate and butyrate in the rumen.Furthermore,an in vivo study demonstrated that dietary supplementation with P.distasonis F4 significantly increased the ADG of pre-weaning calves.Conclusions This study represents the first isolation of P.distasonis F4 from rumen,highlighting its potential as a probiotic strain for improving rumen development and growth performance in ruminants.展开更多
[Objective] The research aimed to search and obtain the fermentation method of hyaluronic acid with the high yield.[Method] In the production process of hyaluronic acid by the microbial fermentation method,the influen...[Objective] The research aimed to search and obtain the fermentation method of hyaluronic acid with the high yield.[Method] In the production process of hyaluronic acid by the microbial fermentation method,the influence of substrate concentration on the fermentation was explored.[Result] The glucose had the biggest influence on the hyaluronic acid fermentation.The low concentration of glucose only could synthetize a little bacteria and hyaluronic acid,and the high concentration of glucose could inhibit the growth of bacteria and the formation of hyaluronic acid.Via the exploratory experiment,the fed-batch fermentation could disarm the substrate inhibition.The concrete method was adding 2% glucose before the start of fermentation,and adding 2% glucose at the 14th hour of fermentation,and adding 2% glucose again at the 22nd hour of fermentation.[Conclusion] In the microbial fermentation process,the fed-batch fermentation could disarm the substrate inhibition and obtain the hyaluronic acid with the larger relative molecular mass and the higher yield.展开更多
Cyclosporin A fermentation residue(CFR)is a type of organic waste generated during the production of cyclosporin A,which are abundant in nutrients including organic matter,phosphorus,nitrogen and potassium.Inappropria...Cyclosporin A fermentation residue(CFR)is a type of organic waste generated during the production of cyclosporin A,which are abundant in nutrients including organic matter,phosphorus,nitrogen and potassium.Inappropriate handling of CFR not only waste valuable bioresources,but may also lead to the cyclosporin A and associated resistance genes into the natural environment,posing a significant threat to ecological system and human health.Land application was an effective way to resource recovery of CFR after aerobic composting(CAC).This study investigated the impact of CAC on soil fertility and environmental safety.The results indicated that CAC could improve soil nutrient contents and enhance enzyme activities.CAC altered the diversity and community composition of soil bacteria,resulting in an increase in the abundance of relevant bacteria beneficial for organic matter decomposition and cyclosporin A degradation.The introduced cyclosporin A(71.69μg/kg)completely degraded within 20 days due to soil biodegradation.The significantly increased abundance of intIl,mdr3,pgp,TSR and pmra in the soil cultivation early stage were restored to the soil background level within 90 days,indicating a reduced risk of antimicrobial resistance.The results demonstrated that reasonable land application of CAC could improve soil fertility without antimicrobial resistance risk,which is helpful for evaluating the resource utilization value and environmental risks of antibiotic fermentation residue after aerobic composting.展开更多
In-depth knowledge of the microbes responsible for biogenic amine(BA)production during soy sauce fermentation remains limited.Herein,the variations in the BA profiles,microbial communities,and microbes involved in BA ...In-depth knowledge of the microbes responsible for biogenic amine(BA)production during soy sauce fermentation remains limited.Herein,the variations in the BA profiles,microbial communities,and microbes involved in BA production during the fermentation of soy sauce through Japanese-type(JP)and Cantonese-type(CP)processes were compared.BA analysis revealed that the most abundant BA species were putrescine,tyramine,and histamine in the later three stages(1187.68,785.16,and 193.20 mg/kg on average,respectively).The BA profiles differed significantly,with CP samples containing higher contents of putrescine,tyramine,and histamine(P<0.05)at the end of fermentation.Metagenomic analysis indicated that BA-producing genes exhibited different abundance profiles,with most genes,including spe A,spe B,arg,spe E,and tyr DC,having higher abundances in microbial communities during the CP process.In total,15 high-quality metagenome-assembled genomes(MAGs)were retrieved,of which 10 encoded at BA production-related genes.Enterococcus faecium(MAG10)and Weissella paramesenteroides(MAG5)might be the major tyramine producers.The high putrescine content in CP might be associated with the high abundance of Staphylococcus gallinarum(MAG8).This study provides a comprehensive understanding of the diversity and abundance of genes involved in BA synthesis,especially at the species level,during food fermentation.展开更多
In this work, Staphylococcus epidermidis (S. epidermidis) was used to prepare the fermentation broths with antioxidant activity. Through the optimization of the carbon source, three kinds of S. epidermidis fermentatio...In this work, Staphylococcus epidermidis (S. epidermidis) was used to prepare the fermentation broths with antioxidant activity. Through the optimization of the carbon source, three kinds of S. epidermidis fermentation broth were obtained and designated as SFB, Gly-SFB, and Glu-SFB, which were cultivated in beef protein medium and the beef protein medium supplemented with glycerol or glucose, respectively. The differences in antioxidant efficacy of SFB, Gly-SFB and Glu-SFB were investigated by evaluating intracellular ROS fluorescence intensity, SOD enzyme activity and MDA concentration. Gly-SFB and Glu-SFB exhibited a greater capacity to eliminate ROS as compared to that of SFB. The intracellular SOD enzyme activity increased as the concentrations of SFB and Gly-SFB increased. Nevertheless, the intracellular SOD enzyme activity was the highest after the treatment with Glu-SFB at the low concentrations. The intracellular MDA content reached a lower value after the treatment with Gly-SFB and Glu-SFB at lower concentrations, which was opposite to the case after the treatment with SFB. WB indicated that the S. epidermidis fermentation broth regulated the expression of relevant proteins in the Nrf2-Keap1 signaling pathway to exhibit the antioxidant effects. This indicates that the S. epidermidis fermentation broth promotes the expression of relevant proteins in the Nrf2-Keap1 signaling pathway, consequently, antioxidant benefits were exerted. The fermentation broth that were prepared by incorporating glycerol or glucose into the culture medium can augment their antioxidant activity.展开更多
基金Supported by the National Natural Science Foundation of China （20306026 and 20876141） and the National Basic Research program of China （2007CB707805）.
文摘5-Aminolevulinic acid （ALA） is a common precursor for tetrapyrrole compounds in all kinds of organ isms and has wide applications in agriculture and medicines. In this study, a new strategy, i.e. short-term dissolved oxygen （DO） shock during aerobic fermentation, was introduced to produce 5-aminolevulinic acid with a recombi-nant E. coli. Effects of duration time of DO shock operation on plasmid concentration, intracellular ALA synthase （ALAS） activity and ALA production were investigated in Erlenmeyer shake flasks. The results indicated that both ALAS activity and ALA yield were enhanced in an anaerobic operation of 45 rain in the early exponential phase during fermentation, while they decreased when the anaerobic operation time was further increased to 60 rain. The DO shock protocol was confirmed with the fed-batch fermentation in a 15 L fermenter and the ALA production achieved 9.4 g.L-1 （72 mmol.L-1）, which is the highest yield in the fermentation broth reported up to now.
基金Partially suppored by a grant for the U K DTI- China MOST Collaborative Research
文摘L-(+)-Lactic acid production from corncob hydrolysate as a cheap carbohydrate source by fed-batch fermentation of Rhizopus oryzaeHZS6 was studied. After 96 h of fermentation in a 5 L fermentor, the final concentration of ammonium L-(+)-lactate, average productivity(based on initial xylose concentration) and maximum dry cell weight were 132.4 g/L, 1.38 g/(L·h), and 8.9 g/L respectively. The optical purity of L-(+)-lactate was 98.8%.
基金Supported by the National Natural Science Foundation of China （20676013）
文摘An iterative optimization strategy for fed-batch fermentation process is presented by combining a run-to-run optimization with swarm energy conservation particle swarm optimization (SEC-PSO). SEC-PSO, which is designed with the concept of energy conservation, can solve the problem of premature convergence frequently appeared in standard PSO algorithm by partitioning its population into several sub-swarms according to the energy of the swarm and is used in the optimization strategy for parameter identification and operation condition optimization. The run-to-run optimization exploits the repetitive nature of fed-batch processes in order to deal with the optimal problems of fed-batch fermentation process with inaccurate process model and unsteady process state. The kinetic model parameters, used in the operation condition optimization of the next run, are adjusted by calculating time-series data obtained from real fed-batch process in the run-to-run optimization. The simulation results show that the strategy can adjust its kinetic model dynamically and overcome the instability of fed-batch process effectively. Run-to-run strategy with SEC-PSO provides an effective method for optimization of fed-batch fermentation process.
文摘Bioreactor operation requires continuous monitoring of fermentation parameters and real-time control over bioreactor devices. Remote monitoring and control of the bioreactor＇s computer via the Internet avoids the necessity of personnel being continually onsite during operation. A two liter Sartorius-stedim Biostat~ A Plus fermentation system was networked and interfaced with the commercial software from GoToMyPC to allow remote control of the fermentation system utilizing the internet. The fermentation vessel was equipped with hardware calibrated for monitoring and controlling culture parameters during experimentations. The uniform resource locator controlled night-vision web camera allowed continuous monitoring of the glass fermentation vessel during the day and at night. The main window screen of the laboratory computer can be securely accessed from any portable device （i.e. laptop） capable of establishing an Internet connection and executing the commercial software from GoToMyPC. The secured internet protocol address, provided by GoToMyPC, assures that the system can only be controlled by authorized users who have been given access to the account. This interface permits the remote control of the Biostat A Plus fermentation system and possibly other automated or potentially automated culturing systems at the convenience of the user（s）.
基金supported by the Open Project Program,State key Laboratory of Bioreactor Engineering/ECUSTthe Natural Science Foundation of China(No.60174024).
文摘An on-line scheduling algorithm to maximize gross profit of penicillin fed-batch fermentation is proposed. According to the on-line classification method, fed-batch fermentation batches are classified into three categories. Using the scheduling strategy, the optimal termination sequence of batches is obtained. Pseudo on-line simulations for testing the proposed algorithm with the data from industrial scale penicillin fermentation are carried out.
基金supported by the National Natural Science Foundation of China(No.21076148 and No.31270087)Plan of Tianjin Science and Technology Support(11ZCKFSY0100)
基金supported by the Research Start-up Foundation for Introduced Talent of Qufu Normal University(609601)。
文摘[Background]Surfactin is a biosurfactant with remarkable surface/interfacial activity.Surfactin production suffers from high costs of carbon sources and severe foaming problem during fermentation.Unreasonable utilization of soybean residue(okara)can cause resource waste and environmental pollution.[Objective]To achieve sustainable production of surfactin and valueadded conversion of okara,we explored foam-free production of surfactin by Bacillus subtilis using okara as a low-cost substrate and evaluated its application prospects.[Methods]We evaluated and compared the feasibility of B.subtilis utilizing okara to synthesize surfactin through liquid and solid-state fermentation methods.Biosurfactants were extracted from solid-state culture via a weak alkaline water extraction method.The products were identified by HPLC-MS,and the physicochemical properties of the produced surfactin were analyzed.The solid-state medium for fermentation of okara was optimized by the response surface method.The viable count of B.subtilis in solid-state fermentation residue was determined by the plate colony counting method.[Results]The conversion rates of okara to surfactin were 0.6%−0.8%and 1.2%−1.5%in liquid and solid-state fermentation,respectively.Interestingly,solid-state fermentation of okara by B.subtilis achieved both high-yield and foam-free production of surfactin.Five surfactin homologues were produced from okara,mainly including surfactin-C13(34.16%),surfactin-C_(14)(23.95%),and surfactin-C_(15)(35.14%).The produced surfactin,with a critical micelle concentration of 35.0 mg/L,decreased water surface tension to(26.0±0.1)mN/m and emulsified crude oil with emulsifying activity index(EI24)(73.1±3.2)%.It was stable at 4−121℃,pH 5.0−11.0,and NaCl<150 g/L.Okara,NH_(4)Cl,and CaCl_(2)·2H_(2)O were significant components in the solid-state medium.The surfactin yield was increased by 52.1%through solid-state medium optimization.Adding wheat straw further enhanced surfactin production by improving aeration in the solid-state medium.B.subtilis AnPL-1 produced(263.2±7.8)mg surfactin in the optimized solid-state medium containing 14.8 g okara and 1.5 g wheat straw.The conversion rate of okara to surfactin was enhanced to 1.8%.In addition,the residue of solid-state fermentation was expected to be microbial fertilizer since it contained 4.27×10^(10)CFU/g of B.subtilis.[Conclusion]This study established a promising way for foam-free production of surfactin and value-added conversion of okara.
基金financed by the Green Fund of the Hellenic Ministry of Environment and Energy,under the funding program“National Environment and Innovation Activities 2022”,Priority Axis“Research&Application”,Project“Sustainable technology for converting pomegranate residues into bioproducts and bioactive compounds”with the acronym“POMEGRANATE”.
文摘Pomegranate residues(PRs),namely pomegranate peels and seeds remaining after juice extraction,constitute a significant agro-industrial residue in Greece.Despite their ample content in carbon sources and bioactive compounds,PRs are largely unexploited,with their management being an increasing concern for the pome-granate processing industry.The objective of this study was the development and characterization of a bio-process aiming at the biotechnological valorization of PRs for ethanol production.Specifically,a stepwise investigation was conducted,including(i)the production and chemical characterization of extracts/hydrolysates from PRs using distinct pretreatments not involving organic solvents or enzymatic hydrolysis;(ii)the assessment of the exploitability of a selected hydrolysate as fermentation feedstock using Saccharomyces cerevisiae;and(iii)the advancement of the bioprocess through the joined utilization in the fermentation substrate of PRs and seeded raisins(SRs),another important agro-industrial residue in Greece.The finally developed substrate,comprising a mixture of PRs/SRs extracts at concentrations 60/40%v/v,was used in three fermentation trials,and the fermentation process was quantitatively described using the Aiba model.The developed bioprocess resulted in satisfactorily high bioethanol production with the maximum attained concentration being 50.0±0.6 g/L.The maximum specific growth rate(μ_(max))of S.cerevisiae was estimated to be 0.1351/h and the bioethanol yield(Y_(ps)),namely the amount of produced ethanol/amount of consumed reducing sugars,was estimated to be 0.423 g/g.Hence,PRs can be efficiently used in the development of a fermentation substrate for bioethanol production,providing an economic and environmentally sustainable alternative to conventional feedstocks.
基金financially supported by the National Natural Science Foundation of China(22138004)National Treasure Ecological Research Synergetic Innovation Center.
文摘Environment serves as the pivotal medium to produce fermented food,with fluctuations in environmental factors exerting a profound impact on the modulation of fermentation microbial communities.Such shifts are crucial for the distinctiveness of fermented food flavor and the variability in quality.Chinese liquor(Baijiu)is one of the typical representatives of spontaneous fermented food.In this review,the multifaceted relationship between regional environmental attributes and the fermentation dynamics of Baijiu was examined,with a spotlight on the strong-flavor,sauce-flavor,and light-flavor varieties.It reveals the influence of regional environmental factors and brewing environmental factors on microbial function and metabolism,which results in the formation of unique flavor characteristics of Baijiu.The 9 main factors affecting the microecology of Baijiu fermentation were further explored,including environmental sensitivity,microbial interactions,biogeographic patterns,and key abiotic factors such as temperature and humidity.Environmental factor management is crucial for controlling microbial community in fermentation.Intelligent detection of the fermentation system is combined with artificial intelligence to realize the digitalization of Baijiu fermentation,with a view to further studying the environmental mechanism or quantitative control relationship of natural fermentation,improving the environmental stability of natural fermentation,and promoting the mechanization and intelligence of fermentation production.
文摘The variation in microbiota during pit fermentation is the main reason for the distinct characteristics of the 7 types of base Baijiu in jiang-flavor Baijiu(JFB)brewing.However,the specific structure,succession,and functional differentiation of microbial communities across different fermentation rounds remain unclear.Therefore,this study compared the differences in microbiota structure,environmental factors driving community assembly,and functional differentiations throughout 1–7 rounds(JC1–JC7)of pit fermentation in JFB production.Results showed that Lactobacillus dominated all rounds and complied with declining relative abundance from rounds JC1–JC7.The mould composition was similar in JC3–JC5 while the yeast structure in JC4 was found intermediate between JC3 and JC5.LEf Se analysis unveiled aroma-producing microorganisms as prominent biomarkers in JC1,strong enzyme-producing attributes in JC2,JC6,and JC7 biomarkers,and an enzyme and aroma-producing focus with robust tolerance in JC3–JC5 biomarkers.Acidity mainly regulated the microbial community in the first 4 rounds,with nutrient limitation drove microbial succession from the fifth round onward.Functional predictions underscored enriched amino acid metabolism enzymes in JC6 and JC1,while carbohydrate degradation exhibited predominant enzymatic profiles in JC2,JC6,and JC7.This study laid a foundation for comprehending community composition,succession,and flavor regulatory mechanisms throughout JFB brewing.
基金supported by the Key Special Projects of the Ministry of Science and Technology(SQ2020YFF0404523)the North Anhui Soybean Advantageous Characteristic Industry Cluster Project(2023CYJQ013)+2 种基金the National Natural Science Foundation of China(32172162)the Key Genetic Technologies Research and Development Program of Hefei(2021GJ075)the Young Talents Program of Anhui Academy of Agricultural Science(QNYC-202122).
文摘Okara is produced in large quantities annually in China,but much of it is discarded due to its high content of indigestible dietary fiber(DF),contributing to significant environmental challenges.Recognizing the underexplored medicinal potential of DF,we developed an efficient fermentation method to enhance the bioavailability of okara fiber.In this study,Pediococcus acidilactici IFJ-1,which has strong enzymatic production capabilities and beneficial effects on gastrointestinal flora modulation,was selected to ferment okara.Results showed decreases in viscosity and particle size,optimized surface structure,improved thermal stability and hydration properties,and a significant increase in soluble DF content from 1.85%to 3.91%.To evaluate the physiological effects,hyperlipidemic mouse models were established and subjected to dietary interventions utilizing okara and fermented okara to measure changes in physicochemical parameters,gut microbiota composition,and lipid metabolism.The dietary intervention was effective,particularly in the fermented okara group,showing a 7.3%weight loss,improved blood lipids(triglycerides:‒39.8%,total cholesterol:‒12.8%,low-density lipoprotein cholesterol:‒34.2%,high-density lipoprotein cholesterol:+26.2%),and a 22.2%lower liver index.Gut microbiota analysis revealed that fermented okara positively modulated the microbial community by increasing the abundance of beneficial bacteria(e.g.,Bacteroidota)and reducing the abundance of obesity-associated bacteria(e.g.,Bacillota).Lipid metabolism profiling further demonstrated that fermented okara downregulated harmful lipids(e.g.,(O-acyl)-ω-hydroxy fatty acids,ceramides,and diacylglycerols)while upregulating beneficial phospholipids(e.g.,phosphatidylinositol,phosphatidylserine,phosphatidylethanolamine,lysophosphatidylinositol and lysophosphatidic acid).This study highlights a novel approach for enhancing DF utilization through fermentation,providing valuable insights into strategies for preventing obesity and metabolic diseases.
基金This work is supported by the National Science Foundation of China(Grant Nos.11771008,11171050 and 11371164)the National Science Foundation for the Youth of China(Grant Nos.11201267,11301051,11301081 and 11401073)+3 种基金the Provincial Natural Science Foundation of Fujian(Grant No.2014J05001)the Fundamental Research Funds for Central Universities in China(Grant DUT15LK25)the China Scholorship Council(CSC,No.201506060121)Natural Science Foundation of Shandong Province,China(Grant No.ZR2017MA005).
文摘In the actual microbial fermentation process,excessive or insufficient substrate can produce inhibitory effects on cells growth.The artificial substrate feeding rules by past experiences have great blindness to keep substrate concentration in a given appropriate range.This paper considers that alkali feed depends on pH value of the solution and glycerol feed depends on glycerol concentration of the solution in the uncoupled microbial fed-hatch fermentation process,and establishes a state-dependent switched system in which the flow rates of glycerol and alkali,the number of mode switches,the mode sequence and the switching times are prior unknown.To maximize the yield of target product 1,3-Propanediol(1,3-PD),we formulate a switching optimal control problem with the flow rates of glycerol and alkali,the number of mode switches,the mode sequence and the switching times as decision variables,which is a mixed-integer dynamic programming problem.For solving the mixed-integer dynamic programming problem,the control parametrization technique,the time scaling transformation and the embedded system technology are used to obtain an approximate parameter optimization problem.By using a parallel optimization algorithm,we obtain the optimal control strategies.Under the obtained optimal control strategies,the 1,3-PD yield at the terminal time is increased significantly compared with the previous results.
文摘To investigate the in vitro digestion and fermentation properties of soybean oligosaccharides(SBOS)extracted from defatted soybean meal,the changes in monosaccharide composition and molecular mass were analyzed.Subsequently,the effect of SBOS on microbial community structure and metabolites was studied by 16S rRNA gene sequencing and untargeted metabolomics based on liquid chromatography-mass spectrometry.Results showed that SBOS was not easily enzymolyzed during simulated digestion and could reach the large intestine through the digestive system.The significant decrease in the molecular mass of SBOS after in vitro fermentation indicated its utilization by the gut microbiota,which increased the contents of short-chain fatty acids and lactic acid,thereby reducing the pH of the fermentation broth.Moreover,the core community was found to consist of Blautia,Lactobacillaceae,and Pediococcus.SBOS up-regulated beneficial differential metabolites such as myo-inositol,lactose,and glucose,which were closely related to galactose,amino sugar,and nucleotide sugar metabolism.This study will provide a reference for exploring the relationship between the gut microbiota and the metabolites of SBOS,and provide a basis for the development and application of SBOS as an ingredient for functional products.
基金Supported by the National Natural Science Foundation of China,No.29476248 and Trans-Century Training Program Foundation for the Talents by the State Education Commission.
文摘In this paper,a novel fuzzy neural network model,in which an adjustable fuzzy sub-space was designed by uniform design,has been established and used in fed-batch yeast fermentationas an example.A brand-new optimization sub-network with special structure has been built andgenetic algorithm,guaranteeing the optimization in overall space,is introduced for the feed rateoptimization.On the basis of the model network,the optimal substrate concentration and theoptimal amount of fed-batch at different periods have been studied,aided with the optimizationnetwork and the genetic algorithm separately.The above results can be used as a basis for theestablishment of a fuzzy neural network controller.
基金supported by the National Key Research and Development Program(No.2021YFD1300201)Jilin Provincial Department of Science and Technology Innovation Platform and Talent Special Project(No.20230508090RC).
文摘Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization,energy metabolism,and gut microbiota in growing pigs.Methods Thirty-six growing barrows(47.2±1.5 kg)were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3β-glucan-to-arabinoxylan ratios.In the experiment,nutrient utilization,energy metabolism,fecal microbial community,and production and absorption of short-chain fatty acid(SCFA)of pigs were investigated.In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig’s hindgut.Results The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber.In animal experiments,increasing the dietary apparent viscosity and theβ-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility(AID),apparent total tract digestibility(ATTD),and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter(P<0.05).In addition,increasing dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased gas exchange,heat production,and protein oxidation,and decreased energy deposition(P<0.05).The dietary apparent viscosity andβ-glucanto-arabinoxylan ratios had linear interaction effects on the digestible energy,metabolizable energy,retained energy(RE),and net energy(NE)of the diets(P<0.05).At the same time,the increase of dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased SCFA production and absorption(P<0.05).Increasing the dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria(P<0.05)and the relative abundance of beneficial bacteria.Furthermore,increasing the dietaryβ-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta(P<0.001).Finally,the prediction equations for RE and NE were established.Conclusion Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization,energy metabolism,and pig gut microbiota composition and metabolites.
基金funded by National Key Research and Development Program(2022YFA1304200)Agricultural Science and Technology Innovation Program(CAAS-ASTIP-2023-IFR-04 and CAAS-ZDRW202305)the Beijing Innovation Consortium of Livestock Research System(BAIC05-2023).
文摘Background Rumen microorganisms are key regulators of ruminant growth and production performance.Identifying probiotic candidates through microbial culturomics presents a promising strategy for improving ruminant production performance.Our previous study identified significant differences in rumen microbial communities of Holstein calves with varying average daily gain(ADG).This study aims to identify a target strain based on the findings from multi-omics analysis and literature review,isolating and evaluating the target microbial strains from both the rumen and hindgut contents for their probiotic potential.Results Parabacteroides distasonis,a strain closely associated with ADG,was successfully isolated from calf rumen content cultured with Fastidious Anaerobe Agar(FAA)medium and named Parabacteroides distasonis F4.Wholegenome sequencing and pan-genome analysis showed that P.distasonis F4 possesses a core functional potential for carbohydrate and amino acid metabolism,with the ability to produce propionate,acetate,and lactate.The results of targeted and untargeted metabolomics further validated the organic acid production and metabolic pathways of P.distasonis F4.An in vitro simulated rumen fermentation test showed that supplementation with P.distasonis F4 significantly altered rumen microbial community structure and increased the molar proportions of propionate and butyrate in the rumen.Furthermore,an in vivo study demonstrated that dietary supplementation with P.distasonis F4 significantly increased the ADG of pre-weaning calves.Conclusions This study represents the first isolation of P.distasonis F4 from rumen,highlighting its potential as a probiotic strain for improving rumen development and growth performance in ruminants.
基金Supported by Ningxia Science and Technology Research PlanningItem(NXGG2009-4)~~
文摘[Objective] The research aimed to search and obtain the fermentation method of hyaluronic acid with the high yield.[Method] In the production process of hyaluronic acid by the microbial fermentation method,the influence of substrate concentration on the fermentation was explored.[Result] The glucose had the biggest influence on the hyaluronic acid fermentation.The low concentration of glucose only could synthetize a little bacteria and hyaluronic acid,and the high concentration of glucose could inhibit the growth of bacteria and the formation of hyaluronic acid.Via the exploratory experiment,the fed-batch fermentation could disarm the substrate inhibition.The concrete method was adding 2% glucose before the start of fermentation,and adding 2% glucose at the 14th hour of fermentation,and adding 2% glucose again at the 22nd hour of fermentation.[Conclusion] In the microbial fermentation process,the fed-batch fermentation could disarm the substrate inhibition and obtain the hyaluronic acid with the larger relative molecular mass and the higher yield.
基金supported by the National Natural Science Foundation of China(No.52170138)the National Key Research and Development Program of China(No.2023YFD1900305)+3 种基金Qingdao Agricultural University Doctoral Start-Up Fund(No.6631122003)the Project of Talent IntroductionEducation Program of Youth Innovation Teams in Universities of Shandong Province(2021–05)Shandong Provincial College Youth Innovation Team Program(No.2023KJ169).
文摘Cyclosporin A fermentation residue(CFR)is a type of organic waste generated during the production of cyclosporin A,which are abundant in nutrients including organic matter,phosphorus,nitrogen and potassium.Inappropriate handling of CFR not only waste valuable bioresources,but may also lead to the cyclosporin A and associated resistance genes into the natural environment,posing a significant threat to ecological system and human health.Land application was an effective way to resource recovery of CFR after aerobic composting(CAC).This study investigated the impact of CAC on soil fertility and environmental safety.The results indicated that CAC could improve soil nutrient contents and enhance enzyme activities.CAC altered the diversity and community composition of soil bacteria,resulting in an increase in the abundance of relevant bacteria beneficial for organic matter decomposition and cyclosporin A degradation.The introduced cyclosporin A(71.69μg/kg)completely degraded within 20 days due to soil biodegradation.The significantly increased abundance of intIl,mdr3,pgp,TSR and pmra in the soil cultivation early stage were restored to the soil background level within 90 days,indicating a reduced risk of antimicrobial resistance.The results demonstrated that reasonable land application of CAC could improve soil fertility without antimicrobial resistance risk,which is helpful for evaluating the resource utilization value and environmental risks of antibiotic fermentation residue after aerobic composting.
基金supported by the Natural Science Foundation of Guangdong Province(2022A1515012158)the National Science Foundation of China(41977138)+3 种基金the Construction Project of Teaching Quality and Teaching Reform in Guangdong Province(SJD202001)the General University Project of Guangdong Provincial Department of Education(2021KCXTD070 and 2021ZDZX4072)the Key Project of Social Welfare and Basic Research of Zhongshan City(2020B2010)the Start-up Fund from the Zhongshan Institute at the University of Electronic Science and Technology in China(419YKQN12)。
文摘In-depth knowledge of the microbes responsible for biogenic amine(BA)production during soy sauce fermentation remains limited.Herein,the variations in the BA profiles,microbial communities,and microbes involved in BA production during the fermentation of soy sauce through Japanese-type(JP)and Cantonese-type(CP)processes were compared.BA analysis revealed that the most abundant BA species were putrescine,tyramine,and histamine in the later three stages(1187.68,785.16,and 193.20 mg/kg on average,respectively).The BA profiles differed significantly,with CP samples containing higher contents of putrescine,tyramine,and histamine(P<0.05)at the end of fermentation.Metagenomic analysis indicated that BA-producing genes exhibited different abundance profiles,with most genes,including spe A,spe B,arg,spe E,and tyr DC,having higher abundances in microbial communities during the CP process.In total,15 high-quality metagenome-assembled genomes(MAGs)were retrieved,of which 10 encoded at BA production-related genes.Enterococcus faecium(MAG10)and Weissella paramesenteroides(MAG5)might be the major tyramine producers.The high putrescine content in CP might be associated with the high abundance of Staphylococcus gallinarum(MAG8).This study provides a comprehensive understanding of the diversity and abundance of genes involved in BA synthesis,especially at the species level,during food fermentation.
文摘In this work, Staphylococcus epidermidis (S. epidermidis) was used to prepare the fermentation broths with antioxidant activity. Through the optimization of the carbon source, three kinds of S. epidermidis fermentation broth were obtained and designated as SFB, Gly-SFB, and Glu-SFB, which were cultivated in beef protein medium and the beef protein medium supplemented with glycerol or glucose, respectively. The differences in antioxidant efficacy of SFB, Gly-SFB and Glu-SFB were investigated by evaluating intracellular ROS fluorescence intensity, SOD enzyme activity and MDA concentration. Gly-SFB and Glu-SFB exhibited a greater capacity to eliminate ROS as compared to that of SFB. The intracellular SOD enzyme activity increased as the concentrations of SFB and Gly-SFB increased. Nevertheless, the intracellular SOD enzyme activity was the highest after the treatment with Glu-SFB at the low concentrations. The intracellular MDA content reached a lower value after the treatment with Gly-SFB and Glu-SFB at lower concentrations, which was opposite to the case after the treatment with SFB. WB indicated that the S. epidermidis fermentation broth regulated the expression of relevant proteins in the Nrf2-Keap1 signaling pathway to exhibit the antioxidant effects. This indicates that the S. epidermidis fermentation broth promotes the expression of relevant proteins in the Nrf2-Keap1 signaling pathway, consequently, antioxidant benefits were exerted. The fermentation broth that were prepared by incorporating glycerol or glucose into the culture medium can augment their antioxidant activity.
