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
Primers and probes were established according to the sequences of the alpha-amylase genes of Bacillus. halodurans C-125, Therrnus sp. IM6501, B. stearothermophilus ET-1, and B, acidopullulytics. Primers were designed ...Primers and probes were established according to the sequences of the alpha-amylase genes of Bacillus. halodurans C-125, Therrnus sp. IM6501, B. stearothermophilus ET-1, and B, acidopullulytics. Primers were designed and a 0.2 kb DNA fragment was amplified, the fragment was successfully used for the detection of the amylase Ⅱ gene in a 2 842 bp region from Bacillus halodurans strain 38C1-1.展开更多
In order to obtain pure enzyme with high activity,two amylase producing strains were isolated from soil samples,and named as the strains LZ-10 and LZ-11.According to morphologic observation,physiology and biochemistry...In order to obtain pure enzyme with high activity,two amylase producing strains were isolated from soil samples,and named as the strains LZ-10 and LZ-11.According to morphologic observation,physiology and biochemistry experiments,16S rRNA and gyrB gene analysis,the strains LZ-10 and LZ-11 were identified as Bacillus subtilis.Adopted the method of ammonium sulfate,DEAE-52 anion purify enzyme,finally used polyacrylamide gel electrophoresis(SDS-PAGE)to detect molecular weight.The strain LZ-10 had an amylase activity of 123.3 U·mL^(-1),a purification factor of 6.8,a recovery rate of 69.5% and an optimal temperature of 50℃.The amylase activity of the strain LZ-11 was 59.91 U·mL^(-1),the purification factor was 4.5,the recovery rate was 60.5%,and the optimum temperature was 55℃.The commodity enzyme derived from Bacillus subtilis was 37.5 U·mL^(-1).The relative molecular weight of amylase activity from the two strains was 55 ku.Both thermal stability and pH stability were higher than those of commercialized amylase.展开更多
To explore the germination mechanism of salt-stressed rice improved by exogenous proline, and provide a theoretical basis to rice direct sowing technology for salinized soil, the effects of soaking with proline on ger...To explore the germination mechanism of salt-stressed rice improved by exogenous proline, and provide a theoretical basis to rice direct sowing technology for salinized soil, the effects of soaking with proline on germination status, amylase activity and isoenzyme were studied in this paper. The results showed that germination status including germination energy（GE）, germination rate（GR）, relative germination energy（RGE） and relative germination rate（RGR） significantly decreased as the same as the activities of alpha-amylase, beta-amylase and the total amylase under salt stress. Soaking with exogenous proline improved the germination status of rice under salt stress. Moreover, GE and RGE of salt-stressed rice were improved with increasing of proline concentration at the range of 5-45 mmol ·L-1. Soaking with 15 mmol ·L-1 and 30 mmol ·L-1 proline significantly improved the amylase activities（e.g. alpha-amylase, beta-amylase and total amylase） of rice under salt stress. Salt stress inhibited the express of beta-amylase isoenzyme temporarily, but had few impacts on alpha-amylase isozyme. Soaking with 30 mmol ·L-1 proline brightened District I and increased the width of ＇i＇ brand in District II of alpha-amylase isoenzyme, but had few impacts on beta-amylase isoenzyme. In a word, soaking with proline could effectively alleviate the inhibitory effects of salt stress on seed germination.展开更多
This study aimed to investigate the production of some metabolites （i.e., antibiotics, amylases and cellulases） of terrestrial actinomycetes isolated from medicinal plant rhizosphere soils. Initially, the soil sampl...This study aimed to investigate the production of some metabolites （i.e., antibiotics, amylases and cellulases） of terrestrial actinomycetes isolated from medicinal plant rhizosphere soils. Initially, the soil samples were collected from Camellia sinensis （L） Okuntze., Peuraria mirifca Airy Shaw Suvatabandhua., Ananus comosus Merr., Elephantopus scaber Linn., Orthosiphon grandiforus Bolding., Jatropha multifda Linn. and Senna siamea. To screen and isolate actinomycetes, the soil samples were pretreated by air-drying and subsequent heat incubation. The bacterial isolates exhibiting actinomycetes features were then randomly screened for their production of amylases, cellulases and antibiotics. It was found that 130 isolates （from 136） could produce amylases; 40 （from 107） produced cellulases; and seven （from 45） exhibited antimicrobial activity. The data of this study were preliminary, and yet demonstrated a rich diversity of rhizo-actinomycetes from medicinal plants. Besides, these organisms could be an untapped source for discovering of biotechnologically useful metabolites.展开更多
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Natural Science Foundation of Heilongjiang Province (C9912)
文摘Primers and probes were established according to the sequences of the alpha-amylase genes of Bacillus. halodurans C-125, Therrnus sp. IM6501, B. stearothermophilus ET-1, and B, acidopullulytics. Primers were designed and a 0.2 kb DNA fragment was amplified, the fragment was successfully used for the detection of the amylase Ⅱ gene in a 2 842 bp region from Bacillus halodurans strain 38C1-1.
基金Supported by Young Doctor Fund of Gansu Education Department,China(2021QB-034)。
文摘In order to obtain pure enzyme with high activity,two amylase producing strains were isolated from soil samples,and named as the strains LZ-10 and LZ-11.According to morphologic observation,physiology and biochemistry experiments,16S rRNA and gyrB gene analysis,the strains LZ-10 and LZ-11 were identified as Bacillus subtilis.Adopted the method of ammonium sulfate,DEAE-52 anion purify enzyme,finally used polyacrylamide gel electrophoresis(SDS-PAGE)to detect molecular weight.The strain LZ-10 had an amylase activity of 123.3 U·mL^(-1),a purification factor of 6.8,a recovery rate of 69.5% and an optimal temperature of 50℃.The amylase activity of the strain LZ-11 was 59.91 U·mL^(-1),the purification factor was 4.5,the recovery rate was 60.5%,and the optimum temperature was 55℃.The commodity enzyme derived from Bacillus subtilis was 37.5 U·mL^(-1).The relative molecular weight of amylase activity from the two strains was 55 ku.Both thermal stability and pH stability were higher than those of commercialized amylase.
基金Supported by the Project of Twelfth Five-year Plan for Sci & Tech Research of China in Rural Areas(2011BAD35B02-01)Program of Sci & Tech Research of China(2011BAD16B11)
文摘To explore the germination mechanism of salt-stressed rice improved by exogenous proline, and provide a theoretical basis to rice direct sowing technology for salinized soil, the effects of soaking with proline on germination status, amylase activity and isoenzyme were studied in this paper. The results showed that germination status including germination energy（GE）, germination rate（GR）, relative germination energy（RGE） and relative germination rate（RGR） significantly decreased as the same as the activities of alpha-amylase, beta-amylase and the total amylase under salt stress. Soaking with exogenous proline improved the germination status of rice under salt stress. Moreover, GE and RGE of salt-stressed rice were improved with increasing of proline concentration at the range of 5-45 mmol ·L-1. Soaking with 15 mmol ·L-1 and 30 mmol ·L-1 proline significantly improved the amylase activities（e.g. alpha-amylase, beta-amylase and total amylase） of rice under salt stress. Salt stress inhibited the express of beta-amylase isoenzyme temporarily, but had few impacts on alpha-amylase isozyme. Soaking with 30 mmol ·L-1 proline brightened District I and increased the width of ＇i＇ brand in District II of alpha-amylase isoenzyme, but had few impacts on beta-amylase isoenzyme. In a word, soaking with proline could effectively alleviate the inhibitory effects of salt stress on seed germination.
文摘This study aimed to investigate the production of some metabolites （i.e., antibiotics, amylases and cellulases） of terrestrial actinomycetes isolated from medicinal plant rhizosphere soils. Initially, the soil samples were collected from Camellia sinensis （L） Okuntze., Peuraria mirifca Airy Shaw Suvatabandhua., Ananus comosus Merr., Elephantopus scaber Linn., Orthosiphon grandiforus Bolding., Jatropha multifda Linn. and Senna siamea. To screen and isolate actinomycetes, the soil samples were pretreated by air-drying and subsequent heat incubation. The bacterial isolates exhibiting actinomycetes features were then randomly screened for their production of amylases, cellulases and antibiotics. It was found that 130 isolates （from 136） could produce amylases; 40 （from 107） produced cellulases; and seven （from 45） exhibited antimicrobial activity. The data of this study were preliminary, and yet demonstrated a rich diversity of rhizo-actinomycetes from medicinal plants. Besides, these organisms could be an untapped source for discovering of biotechnologically useful metabolites.
