Prebiotics are non-digestible food supplements (oligosaccharides) which play an important role in stimulating the growth of beneficial bacteria especially Lactobacilli and Bifidobacteria in the colon of the host. Xylo...Prebiotics are non-digestible food supplements (oligosaccharides) which play an important role in stimulating the growth of beneficial bacteria especially Lactobacilli and Bifidobacteria in the colon of the host. Xylooligosaccharides (XOS) are more effective than other oligosaccharides such as fructo-oligosaccharides as dietary supplements. Chemical methods are preferred to produce XOS mixtures with a wide DP range, while enzymatic methods are preferred in the food or pharmaceutical industries to reduce formation of degradation products. With the growing importance of making fuels fromlignocellulosic biomass (LCM) and the increasing demand for XOS, more opportunities are emerging to utilize xylan-rich component generated in biorefinery into high-value products such as XOS that could further lower the cost of LCM derived biofuels.展开更多
Bacterial biofilms are the bacterial aggregates that are embedded in the self-produced matrix of extracellular polymeric substances (EPS) that cause persistent bacterial infections posing significant medical challenge...Bacterial biofilms are the bacterial aggregates that are embedded in the self-produced matrix of extracellular polymeric substances (EPS) that cause persistent bacterial infections posing significant medical challenges. They are recalcitrant to antibiotics and host defenses which make the treatments difficult and costly. Penicillium janthinellum mutant EU2D-21 was found to produce extracellular enzyme complex (amylase, cellulase, protease) under submerged fermentation. Maximum specific enzyme activities were found to be 3.04 IU/mg, 2.61 IU/mg and 3.39 IU/mg for alpha-amylase, cellulase and protease respectively, after 8 days of incubation at 30?C. We evaluated the enzyme complex for its ability to target and degrade the biofilms of different bacteria. We found that it degraded biofilms of Escherichia coli (85.5%), Salmonella enterica (79.72%), Pseudomonas aeruginosa (88.76%) and Staphyloccus aureus (87.42%) within 1 h of incubation at 50?C. The scanning electron microscopy (SEM), quantitation of biofilm removal assay and Crystal violet assay demonstrated that the enzyme complex detached the biofilm exo-polysaccharide matrix and bacteria from the cell surface. These results illustrate the feasibility and benefits of using this enzyme complex as anti-biofilm therapeutics to eradicate biofilms. This can also be used as a promising strategy to improve treatment of multidrug resistant bacterial infections.展开更多
Xylanase is an important enzyme with potential application in the degradation of xylan component in the lignocellulosic biomass. There are very few reports on the production of cellulase free xylanases especially by y...Xylanase is an important enzyme with potential application in the degradation of xylan component in the lignocellulosic biomass. There are very few reports on the production of cellulase free xylanases especially by yeast strains which have great potential in paper and pulp industry in removing the hemicellulose from the treated or untreated pulp. In this study, P. hubeiensis NCIM 3574 isolated in our laboratory produced significant levels of extracellular cellulase free xylanase (2480 IU/g DSS) in solid state fermentation (SSF) using wheat bran and xylan. It also produced high levels of β-xylosidase (198 IU/g DSS) when grown in SSF using ground nut oil cake and xylan. These highest activities were obtained when fermented Koji was extracted with 1% NaCl supplemented with 0.5% of Triton X-100. These are the highest activities reported so far from yeast strains in the available literature. The crude xylanase preparation of P. hubeiensis produced xylooligosaccharides (XOS) without xylose proving its potential for XOS production with no further requirement of downstream processing. The XOS as prebiotic show beneficial effect on gut microflora such as Lactobacilli and Bifidobacteria which suppress the activity of pathogenic organisms. This xylanase also has a potential application as a bio-bleaching agent in paper and pulp industry.展开更多
Food grain storage is a difficult task due to insect infestation and subsequent mycotoxin contaminations which adversely affects the nutritional quality of grains and leading to economic loss. Current research focuses...Food grain storage is a difficult task due to insect infestation and subsequent mycotoxin contaminations which adversely affects the nutritional quality of grains and leading to economic loss. Current research focuses on contact and fumigant toxicity effects of essential oils (EO) and aroma compounds against Sitophilus oryzae and growth inhibition of aflatoxigenic fungi. The EO of Ocimum gratissimum comprised of thymol (46.8%), γ-terpinene (14.04%) along with o-cymene (11.76%). Also, Cymbopogon flexuosus rich in citral (76.3%) and geraniol (84.6%) and Cymbopogon nardus having geraniol (49.24%) and geranyl acetate (20.9%) were all evaluated using a dose of 25 μL (Conc∼833.3 μL/L air) against S. oryzae . All the compounds showed significant mortality (>95%) at 24 h of exposure. The insecticidal property of O. gratissimum oil chemotype showed a strong contact and fumigant toxicity against S. oryzae at a highest dose of 25 μL (Conc∼833.3 μL/L air) within 24 h. It has been further evaluated on three aflatoxigenic fungal strains which showed reduction in growth and aflatoxin content (Aflatoxin B and G), which was markedly reduced upon the treatment. The binary mixture interaction of O. gratissimum oil with monoterpene phenol (carvacrol) was assessed and the specific binary mixture of 80:20 ratio (having additive property) acts as a contact insecticide with 100% mortality. Hence, essential oil of less explored Ocimum species (O. gratissimum ) and its binary mixture could be deployed as potential biorational for control of rice weevil (Sitophilus oryzae ) and aflatoxigenic Aspergillus spp.展开更多
文摘Prebiotics are non-digestible food supplements (oligosaccharides) which play an important role in stimulating the growth of beneficial bacteria especially Lactobacilli and Bifidobacteria in the colon of the host. Xylooligosaccharides (XOS) are more effective than other oligosaccharides such as fructo-oligosaccharides as dietary supplements. Chemical methods are preferred to produce XOS mixtures with a wide DP range, while enzymatic methods are preferred in the food or pharmaceutical industries to reduce formation of degradation products. With the growing importance of making fuels fromlignocellulosic biomass (LCM) and the increasing demand for XOS, more opportunities are emerging to utilize xylan-rich component generated in biorefinery into high-value products such as XOS that could further lower the cost of LCM derived biofuels.
文摘Bacterial biofilms are the bacterial aggregates that are embedded in the self-produced matrix of extracellular polymeric substances (EPS) that cause persistent bacterial infections posing significant medical challenges. They are recalcitrant to antibiotics and host defenses which make the treatments difficult and costly. Penicillium janthinellum mutant EU2D-21 was found to produce extracellular enzyme complex (amylase, cellulase, protease) under submerged fermentation. Maximum specific enzyme activities were found to be 3.04 IU/mg, 2.61 IU/mg and 3.39 IU/mg for alpha-amylase, cellulase and protease respectively, after 8 days of incubation at 30?C. We evaluated the enzyme complex for its ability to target and degrade the biofilms of different bacteria. We found that it degraded biofilms of Escherichia coli (85.5%), Salmonella enterica (79.72%), Pseudomonas aeruginosa (88.76%) and Staphyloccus aureus (87.42%) within 1 h of incubation at 50?C. The scanning electron microscopy (SEM), quantitation of biofilm removal assay and Crystal violet assay demonstrated that the enzyme complex detached the biofilm exo-polysaccharide matrix and bacteria from the cell surface. These results illustrate the feasibility and benefits of using this enzyme complex as anti-biofilm therapeutics to eradicate biofilms. This can also be used as a promising strategy to improve treatment of multidrug resistant bacterial infections.
文摘Xylanase is an important enzyme with potential application in the degradation of xylan component in the lignocellulosic biomass. There are very few reports on the production of cellulase free xylanases especially by yeast strains which have great potential in paper and pulp industry in removing the hemicellulose from the treated or untreated pulp. In this study, P. hubeiensis NCIM 3574 isolated in our laboratory produced significant levels of extracellular cellulase free xylanase (2480 IU/g DSS) in solid state fermentation (SSF) using wheat bran and xylan. It also produced high levels of β-xylosidase (198 IU/g DSS) when grown in SSF using ground nut oil cake and xylan. These highest activities were obtained when fermented Koji was extracted with 1% NaCl supplemented with 0.5% of Triton X-100. These are the highest activities reported so far from yeast strains in the available literature. The crude xylanase preparation of P. hubeiensis produced xylooligosaccharides (XOS) without xylose proving its potential for XOS production with no further requirement of downstream processing. The XOS as prebiotic show beneficial effect on gut microflora such as Lactobacilli and Bifidobacteria which suppress the activity of pathogenic organisms. This xylanase also has a potential application as a bio-bleaching agent in paper and pulp industry.
基金AVR,AR and BK,acknowledges the financial support of UGC NET-JRF Fellowship by University Grant Commissions(UGC),Delhi,IndiaCSV greatly acknowledges the support of CSIR Endophyte Network Project under FBR Scheme(MLP 0048)and HCP31(CSIR-ATLAS Mission)+1 种基金Authors,acknowledge the support of Director,CSIR-Central Food Technological Research Institute Mysore(CFTRI),570020,Karnataka for providing the necessary facilitiesAuthors also thank Ms.M Asha(Sr.Technical officer),CIFS,CSIR-CFTRI for assistance in GC analysis and Mr.Bhavani Eswaran M(Sr.Technical Officer)CIFS,CSIR-CFTRI for GC-MS analysis.(PMC communication number:PMC/2021-22/373).
文摘Food grain storage is a difficult task due to insect infestation and subsequent mycotoxin contaminations which adversely affects the nutritional quality of grains and leading to economic loss. Current research focuses on contact and fumigant toxicity effects of essential oils (EO) and aroma compounds against Sitophilus oryzae and growth inhibition of aflatoxigenic fungi. The EO of Ocimum gratissimum comprised of thymol (46.8%), γ-terpinene (14.04%) along with o-cymene (11.76%). Also, Cymbopogon flexuosus rich in citral (76.3%) and geraniol (84.6%) and Cymbopogon nardus having geraniol (49.24%) and geranyl acetate (20.9%) were all evaluated using a dose of 25 μL (Conc∼833.3 μL/L air) against S. oryzae . All the compounds showed significant mortality (>95%) at 24 h of exposure. The insecticidal property of O. gratissimum oil chemotype showed a strong contact and fumigant toxicity against S. oryzae at a highest dose of 25 μL (Conc∼833.3 μL/L air) within 24 h. It has been further evaluated on three aflatoxigenic fungal strains which showed reduction in growth and aflatoxin content (Aflatoxin B and G), which was markedly reduced upon the treatment. The binary mixture interaction of O. gratissimum oil with monoterpene phenol (carvacrol) was assessed and the specific binary mixture of 80:20 ratio (having additive property) acts as a contact insecticide with 100% mortality. Hence, essential oil of less explored Ocimum species (O. gratissimum ) and its binary mixture could be deployed as potential biorational for control of rice weevil (Sitophilus oryzae ) and aflatoxigenic Aspergillus spp.
