Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial ...Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial acid producing metabolisms,is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes.The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions.Several alkaliphilic acid producing bacteria were isolated in this study.One strain was selected for its superior growth pattern and acid metabolism(termed EEEL02).Based on the phylogenetic analysis,this strain was identified as Bacillus thuringiensis.The optimized fermentation conditions were as follows:pH 10;NaCl concentration 5%;temperature 25℃;EEEL02 preferred glucose and peptone as carbon and nitrogen sources,respectively.Based on optimal fermentation conditions,EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test.Acetic acid,propionic acid and CO2(g)were the major acid metabolites of fermentation,suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism.This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.展开更多
A total of 126 bacterial strains were isolated from soil samples. Among them, 11 isolates were found positive for amylase production. Strain YL produced the largest zone of clearance on plate assay. The isolate YL was...A total of 126 bacterial strains were isolated from soil samples. Among them, 11 isolates were found positive for amylase production. Strain YL produced the largest zone of clearance on plate assay. The isolate YL was identified as Bacillus sp. based on morphological and physiochemical characterization. According to 16S rRNA gene sequencing data, the closest phylogenetic neighbor of strain YL was Bacillus amyloliquefaciens （99.54%）. After that, an optimization of culture conditions was carried out for the improvement of a-amylase production. Response surface methodology （RSM） was applied to evaluate the effect of medium components including wheat bran, cottonseed extract, yeast extract, starch, NaC1 and CaCl2. Three variables （wheat bran, cottonseed extract, and starch）, which were identified to significantly affect amylase production by Plackett-Burman design were further optimized using response surface methodology of Box-Behnken design （BBD）. The optimal concentrations estimated for each variable related to the maximum of amylase activity （86 kU/mL） were 10.80 g/L wheat bran, 9.90 g/L cottonseed extract, 0.5 g/L starch, 2.0 g/L yeast extract, 5.00 g/L NaCl and 2.00 g/L CaC12. The fermentation using optimized culture medium allowed a significant increase in amylase production （by 3-fold）. The improvement in the a-amylase production after optimization process can be considered adequate for large-scale applications.展开更多
The production and properties of the biosurfactant synthesized by Bacillus subtilis CCTCC AB93108 were studied. The maximum concentration of the surfactant is 1.64 g/L when the bacteria grow in a medium supplemented w...The production and properties of the biosurfactant synthesized by Bacillus subtilis CCTCC AB93108 were studied. The maximum concentration of the surfactant is 1.64 g/L when the bacteria grow in a medium supplemented with glucose as carbon sources. The isolated biosurfactant is a complex of protein and polysaccharide without lipids. It reduces the surface tension of distilled water to 45.9 mN/m, and its critical micelle concentration (CMC) is 2.96 g/L. It can stabilize emulsions of several aromatic and aliphatic hydrocarbons, such as benzene, xylene, n-pentane, n-nonane, gasoline and diesel oil. It presents high emulsification activity and stability in a wide range of temperature (4-100 ℃) and a long period of duration.展开更多
Performance of continuous 1-butanol production process by Clostridium bacteria is complicated by alternation of acidogenic and solventogenic phases during fermentation what correlates with culture growth and sporulati...Performance of continuous 1-butanol production process by Clostridium bacteria is complicated by alternation of acidogenic and solventogenic phases during fermentation what correlates with culture growth and sporulation, respectively. However, the strain Clostridium pasteurianum NRRL B598 showed diverse pattern of solvents production when butanol production started during exponential growth phase in batch cultivation. If cultivated under glucose limited conditions with dilution rate 0.03 hl, constant product concentration was almost achieved. By contrast, glucose non-limited continuous experiment operated with dilution rate 0.07 h-1 lead to mutually adverse oscillations of product and glucose concentrations. Regarding the process economy, glucose limited continuous cultivation seems to be superior due to utilization of total supplied glucose amount, advantageous butanol/acetone ratio and higher butanol yield.展开更多
In this research the results of studies on optimization of alkaline protease production by Bacillus licheniformis are reported. The parameters, which were taken into consideration, are pH, temperature, time course of ...In this research the results of studies on optimization of alkaline protease production by Bacillus licheniformis are reported. The parameters, which were taken into consideration, are pH, temperature, time course of enzyme production, stirring rate and kinetics parameters. The effect of various carbon and nitrogen sources in culture medium compound on enzyme production was also considered The result of optimization revealed that maximum protease production was obtained at 37 ℃, pH equivalent tol 0.0 and with 150 rpm will occur after 72 hours. By comparing the effect of 5 carbon sources （maltose, glucose, starch, casein and lactose） in enzyme production, it has been known that using lactose will increase about 1.5 times enzyme production, compared to condition in which maltose is used. The result of studies on the effect of five nitrogen sources （i.e., peptone, tryptone, ammonium sulfate, urea and corn steep liquor） shows that corn steep liqour increases enzyme production more than others, while peptone can also be considered as a good nitrogen source; but, ammonium sulfate and urea reduce enzyme production considerably. It was concluded that protease production occurs in the stationary phase of growth. Studying the kinetics parameters resulted that the best model for the enzyme above is Lineweaver-Burk model according to which Km is 0.64 mmol and Vmax is 88 lamol/min.展开更多
To improve antagonistic metabolites production of Bacillus subtilis strain BS501a, physical parameters of fermentation and metal inorganic salts in medium, namely initial pH value, culture temperature, fermentation ti...To improve antagonistic metabolites production of Bacillus subtilis strain BS501a, physical parameters of fermentation and metal inorganic salts in medium, namely initial pH value, culture temperature, fermentation time, concentrations of CaC12, FeSO4, ZnSO4, MnSO4 and MgSO4, were optimized using one-factor-at-a-time and orthogonal tests. The results show that the optimal physical parameters of fermentation are an initial pH of 7.0, a culture temperature of 30 ~C, and a fermentation time of 48 h. The optimal concentrations of metal inorganic salts in basal medium are 10.2 mmol/L CaCl2, 0.4 mmol/L FeSO4, 3.5 mmol/L ZnSO4, 0.6 mmol/L MnSO4 and 2.0 mmol/L MgSO4. Among the metal inorganic salts, MgSO4 and MnSO4 play important roles in the improvement of the antagonistic metabolites production of B. subtilis strain BS501a; especially, MgSO4 contributes a highly significant effect. The average diameter of inhibition zone of the BS501a filtered fermentation supernatant （FFS） cultured in the optimal fermentation conditions against Magnaporthe grisea DWBJ329 reaches 71.4 mm, and there is 2.4-fold increase in antifungal activity as compared with 21.2 mm under the pre-optimized conditions.展开更多
Bacillus subtilis produces many chemlcally-dwerse seconaary metaDolltes or interest to chemists ano biologlsts. Based on this, this review gives a detailed overview of the natural components produced by B. subtilis in...Bacillus subtilis produces many chemlcally-dwerse seconaary metaDolltes or interest to chemists ano biologlsts. Based on this, this review gives a detailed overview of the natural components produced by B. subtilis including cyclic lipopeptides, polypeptides, proteins （enzymes）, and non-peptide products. Their structures, bioactive ac- tivities and the relevant variants as novel lead structures for drug discovery are also described. The challenging effects of fermentation metabolites, isolation and purification, as well as the overproduction of bioactive com- pounds from B. subtilis by metabolic engineering, ＇~ere also highlighted. Systematically exploring biosynthetic routes and the functions of secondary metabolites from 13. subtilis may not only be beneficial in improving yields of the products, but also in helping them to be used in food industry and public medical service on a large-scale.展开更多
The production of cellulase in Bacillus amyloliquefaciens UNPDV-22 was optimized using response surface methodology （RSM）. Central composite design （CCD） was used to study the interactive effect of culture conditi...The production of cellulase in Bacillus amyloliquefaciens UNPDV-22 was optimized using response surface methodology （RSM）. Central composite design （CCD） was used to study the interactive effect of culture conditions （temperature, pH, and inoculum） on cellulase activity. Results suggested that temperature and pH all have significant impact on cellulase production. The use of RSM resulted in a 96% increase in the cellulase activity over the control of non-optimized basal medium. Optimum cellulase production of 13 U/mL was obtained at a temperature of 42.24 ℃, pH of 5.25, and inoculum size of 4.95% （v/v） in a fermentation medium containing wheat bran, soybean meal and malt dextrin as major nutritional factors.展开更多
The disadvantages of the long term application of Tilemsi natural phosphate （TNP） on maize （Zea mays L.） production has come out because of its low P availability. Some functional soil microbes, such as phosphate ...The disadvantages of the long term application of Tilemsi natural phosphate （TNP） on maize （Zea mays L.） production has come out because of its low P availability. Some functional soil microbes, such as phosphate dissolving bacteria, have great potential in improvement of P solubility from TNP and P uptake by plants. The present study aimed to isolate and characterize typical phosphate dissolving bacterial strains （Bacillus subtilis） from Malian soils, and investigate their role in P uptake by maize grown in soils amended with TNP. The experimental design was a split plot with three main plots of fertilizers sources, i.e., natural phosphate, commercial fertilizer and without fertilizer, and with seven sub-plots of six microorganisms plus the control. The field experiment results have shown that the maize inoculated with the phosphate dissolving bacteria was improved in seed germination, plant growth, plant production （increase yield by 42%）, grain and aerial dry biomass （P） content of 34% and 64%, respectively. They have also shown that the locally available TNP can be used by the Malians farmers in maize culture and have comparable production to the one obtained with the costly imported commercial phosphate fertilizer, like the complex cereal. The project has provided information for the combined use of the Mali TNP and phosphate dissolving bacteria Bacillus subtilis subsp, subtilis （T）： DSM 10 in improvement of maize production in the country.展开更多
基金Projects(41877511,41842020)supported by the National Natural Science Foundation of ChinaProject(502221703)supported by the Innovative Project of Independent Exploration of Central South University,China
文摘Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial acid producing metabolisms,is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes.The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions.Several alkaliphilic acid producing bacteria were isolated in this study.One strain was selected for its superior growth pattern and acid metabolism(termed EEEL02).Based on the phylogenetic analysis,this strain was identified as Bacillus thuringiensis.The optimized fermentation conditions were as follows:pH 10;NaCl concentration 5%;temperature 25℃;EEEL02 preferred glucose and peptone as carbon and nitrogen sources,respectively.Based on optimal fermentation conditions,EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test.Acetic acid,propionic acid and CO2(g)were the major acid metabolites of fermentation,suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism.This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.
基金Project(31000350) supported by the National Natural Science Foundation of ChinaProject(2010CB630902) supported by the National Basic Research Program of China
文摘A total of 126 bacterial strains were isolated from soil samples. Among them, 11 isolates were found positive for amylase production. Strain YL produced the largest zone of clearance on plate assay. The isolate YL was identified as Bacillus sp. based on morphological and physiochemical characterization. According to 16S rRNA gene sequencing data, the closest phylogenetic neighbor of strain YL was Bacillus amyloliquefaciens （99.54%）. After that, an optimization of culture conditions was carried out for the improvement of a-amylase production. Response surface methodology （RSM） was applied to evaluate the effect of medium components including wheat bran, cottonseed extract, yeast extract, starch, NaC1 and CaCl2. Three variables （wheat bran, cottonseed extract, and starch）, which were identified to significantly affect amylase production by Plackett-Burman design were further optimized using response surface methodology of Box-Behnken design （BBD）. The optimal concentrations estimated for each variable related to the maximum of amylase activity （86 kU/mL） were 10.80 g/L wheat bran, 9.90 g/L cottonseed extract, 0.5 g/L starch, 2.0 g/L yeast extract, 5.00 g/L NaCl and 2.00 g/L CaC12. The fermentation using optimized culture medium allowed a significant increase in amylase production （by 3-fold）. The improvement in the a-amylase production after optimization process can be considered adequate for large-scale applications.
基金Project(IRT0719) supported by the Program for Changjiang Scholars and Innovative Research Team in University of China Project (2004AA649370) supported by the National High-Tech Research and Development Program of China+1 种基金 Projects(50425927, 50225926) supported by the Natural Foundation for Distinguished Young Scholars Project(2007F3102) supported by Technology Foundation for Creative Young Scholars of Fujian Province, China
文摘The production and properties of the biosurfactant synthesized by Bacillus subtilis CCTCC AB93108 were studied. The maximum concentration of the surfactant is 1.64 g/L when the bacteria grow in a medium supplemented with glucose as carbon sources. The isolated biosurfactant is a complex of protein and polysaccharide without lipids. It reduces the surface tension of distilled water to 45.9 mN/m, and its critical micelle concentration (CMC) is 2.96 g/L. It can stabilize emulsions of several aromatic and aliphatic hydrocarbons, such as benzene, xylene, n-pentane, n-nonane, gasoline and diesel oil. It presents high emulsification activity and stability in a wide range of temperature (4-100 ℃) and a long period of duration.
文摘Performance of continuous 1-butanol production process by Clostridium bacteria is complicated by alternation of acidogenic and solventogenic phases during fermentation what correlates with culture growth and sporulation, respectively. However, the strain Clostridium pasteurianum NRRL B598 showed diverse pattern of solvents production when butanol production started during exponential growth phase in batch cultivation. If cultivated under glucose limited conditions with dilution rate 0.03 hl, constant product concentration was almost achieved. By contrast, glucose non-limited continuous experiment operated with dilution rate 0.07 h-1 lead to mutually adverse oscillations of product and glucose concentrations. Regarding the process economy, glucose limited continuous cultivation seems to be superior due to utilization of total supplied glucose amount, advantageous butanol/acetone ratio and higher butanol yield.
文摘In this research the results of studies on optimization of alkaline protease production by Bacillus licheniformis are reported. The parameters, which were taken into consideration, are pH, temperature, time course of enzyme production, stirring rate and kinetics parameters. The effect of various carbon and nitrogen sources in culture medium compound on enzyme production was also considered The result of optimization revealed that maximum protease production was obtained at 37 ℃, pH equivalent tol 0.0 and with 150 rpm will occur after 72 hours. By comparing the effect of 5 carbon sources （maltose, glucose, starch, casein and lactose） in enzyme production, it has been known that using lactose will increase about 1.5 times enzyme production, compared to condition in which maltose is used. The result of studies on the effect of five nitrogen sources （i.e., peptone, tryptone, ammonium sulfate, urea and corn steep liquor） shows that corn steep liqour increases enzyme production more than others, while peptone can also be considered as a good nitrogen source; but, ammonium sulfate and urea reduce enzyme production considerably. It was concluded that protease production occurs in the stationary phase of growth. Studying the kinetics parameters resulted that the best model for the enzyme above is Lineweaver-Burk model according to which Km is 0.64 mmol and Vmax is 88 lamol/min.
基金Project(2010A210003) supported by Henan Province Natural Sciences Research PlanProject(0910SGYS34370-2) supported by Zhengzhou City Science and Technology Research PlanProject supported by the Youth Backbone Teacher of Universities in Henan Province Grants Plan
文摘To improve antagonistic metabolites production of Bacillus subtilis strain BS501a, physical parameters of fermentation and metal inorganic salts in medium, namely initial pH value, culture temperature, fermentation time, concentrations of CaC12, FeSO4, ZnSO4, MnSO4 and MgSO4, were optimized using one-factor-at-a-time and orthogonal tests. The results show that the optimal physical parameters of fermentation are an initial pH of 7.0, a culture temperature of 30 ~C, and a fermentation time of 48 h. The optimal concentrations of metal inorganic salts in basal medium are 10.2 mmol/L CaCl2, 0.4 mmol/L FeSO4, 3.5 mmol/L ZnSO4, 0.6 mmol/L MnSO4 and 2.0 mmol/L MgSO4. Among the metal inorganic salts, MgSO4 and MnSO4 play important roles in the improvement of the antagonistic metabolites production of B. subtilis strain BS501a; especially, MgSO4 contributes a highly significant effect. The average diameter of inhibition zone of the BS501a filtered fermentation supernatant （FFS） cultured in the optimal fermentation conditions against Magnaporthe grisea DWBJ329 reaches 71.4 mm, and there is 2.4-fold increase in antifungal activity as compared with 21.2 mm under the pre-optimized conditions.
基金Supported by the National Natural Science Foundation of China(21376215)the National Science and Technology Major Project of New Drug,China(2012ZX09103101-075)+2 种基金the Innovative Research Platform co-constructed by Zhejiang University and Taizhou City,and the Science and Technology Project of Zhejiang Province(2014C33174)the Major State Basic Research Development Program of China(2011CB710803)the National High-Tech Research and Development Program of China(2012AA022302)
文摘Bacillus subtilis produces many chemlcally-dwerse seconaary metaDolltes or interest to chemists ano biologlsts. Based on this, this review gives a detailed overview of the natural components produced by B. subtilis including cyclic lipopeptides, polypeptides, proteins （enzymes）, and non-peptide products. Their structures, bioactive ac- tivities and the relevant variants as novel lead structures for drug discovery are also described. The challenging effects of fermentation metabolites, isolation and purification, as well as the overproduction of bioactive com- pounds from B. subtilis by metabolic engineering, ＇~ere also highlighted. Systematically exploring biosynthetic routes and the functions of secondary metabolites from 13. subtilis may not only be beneficial in improving yields of the products, but also in helping them to be used in food industry and public medical service on a large-scale.
文摘The production of cellulase in Bacillus amyloliquefaciens UNPDV-22 was optimized using response surface methodology （RSM）. Central composite design （CCD） was used to study the interactive effect of culture conditions （temperature, pH, and inoculum） on cellulase activity. Results suggested that temperature and pH all have significant impact on cellulase production. The use of RSM resulted in a 96% increase in the cellulase activity over the control of non-optimized basal medium. Optimum cellulase production of 13 U/mL was obtained at a temperature of 42.24 ℃, pH of 5.25, and inoculum size of 4.95% （v/v） in a fermentation medium containing wheat bran, soybean meal and malt dextrin as major nutritional factors.
文摘The disadvantages of the long term application of Tilemsi natural phosphate （TNP） on maize （Zea mays L.） production has come out because of its low P availability. Some functional soil microbes, such as phosphate dissolving bacteria, have great potential in improvement of P solubility from TNP and P uptake by plants. The present study aimed to isolate and characterize typical phosphate dissolving bacterial strains （Bacillus subtilis） from Malian soils, and investigate their role in P uptake by maize grown in soils amended with TNP. The experimental design was a split plot with three main plots of fertilizers sources, i.e., natural phosphate, commercial fertilizer and without fertilizer, and with seven sub-plots of six microorganisms plus the control. The field experiment results have shown that the maize inoculated with the phosphate dissolving bacteria was improved in seed germination, plant growth, plant production （increase yield by 42%）, grain and aerial dry biomass （P） content of 34% and 64%, respectively. They have also shown that the locally available TNP can be used by the Malians farmers in maize culture and have comparable production to the one obtained with the costly imported commercial phosphate fertilizer, like the complex cereal. The project has provided information for the combined use of the Mali TNP and phosphate dissolving bacteria Bacillus subtilis subsp, subtilis （T）： DSM 10 in improvement of maize production in the country.
