The 46 strains that produced inulase were screened from rhizosphere soil where Jerusalem artichoke was planted in Qinghai.One strain with high inulinase productivity was obtained through further screening and the enzy...The 46 strains that produced inulase were screened from rhizosphere soil where Jerusalem artichoke was planted in Qinghai.One strain with high inulinase productivity was obtained through further screening and the enzyme activity was6.67 U/ml.This inulinase was exonuclease.Through determination and analysis of the r DNA-ITS sequence,and analysis of morphology,the fungus was identified as Actinomucor elegans.展开更多
Strains from the cellulose-containing environment were collected.Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium)and reelection(by filter-paper i...Strains from the cellulose-containing environment were collected.Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium)and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium)indicated that five strains obtained were best suited for high performance cellulose degradation.Determination of sodium carboxymethylcellulose activity(CMCA)and filter paper activity(FPA)was accomplished for each of the five.The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF)and simultaneous saccharification and fermentation(SSF)respectively.展开更多
[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to ...[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to the traditional microbial culture method, with trans-anethole as the sole carbon source, through enrichment culture and separation and purification, preliminary screening by thin layer chromatography and re-screening by high-performance liquid chromatography, strains that degraded trans-anethole to produce anisic acid were obtained, and 16 S rDNA sequencing and phylogenetic tree construction were performed for genetic analysis. [Results] Eleven strains that degraded trans-anethole to produce anisic acid were obtained, among which strain NT2 that produced anisic acid with a relatively high efficiency was initially identified as Pseudomonas sp. The strain’s trans-anethole degradation rate was 45.41%, and the molar production rate and cumulative concentration of anisic acid were 21.80% and 1.96 g/L, respectively. [Conclusions] Strain NT2 has a strong ability to degrade trans-anethole to produce anisic acid, and can enrich strain resources for degradation of trans-anethole to anisic acid through microbial conversion.展开更多
In this paper, eleven strains, which were screened strictly from raw royal jelly, soil andhoneycomb etc. by meansof dilution plate and spread plate methods, were cultured at 28℃ for 60 h with shaking. To determine wh...In this paper, eleven strains, which were screened strictly from raw royal jelly, soil andhoneycomb etc. by meansof dilution plate and spread plate methods, were cultured at 28℃ for 60 h with shaking. To determine whether they could yield10-Hydroxy-2-decenoic acid during fermentation, gas chromatography and gas chromatography-mass spectrometry methodswere used. The results showed that the strains BH002 and BH004, were both identified as Crytococcaceae, where BH002was primarily classified into Candida for possessing the abilities. The 10-HDA productivity of Candida BH002 and that ofBH004 were 0.327% and 0.2648% respectively.展开更多
Antibiotics residues have been accumulating in the environment day by day due to overuse of antibiotics.Recalcitrant antibiotic residues,such as tylosin(TYL),can cause serious environmental problems,which makes it imp...Antibiotics residues have been accumulating in the environment day by day due to overuse of antibiotics.Recalcitrant antibiotic residues,such as tylosin(TYL),can cause serious environmental problems,which makes it important to eliminate TYL from the environment.It is important to eliminate TYL from the environment.In this study,a strain was isolated and purified from fermentation by-product that came from a TYL production factory.The TYL degrading strain was identified by its morphology,physiological and biochemical reactions and sequencing the PCR-amplified fragments of its 16 S r DNAcoding genes.The temperature,shaking speed,initial TYL concentration,p H and inoculum sizes were investigated under simulated conditions by using single factor tests.The results showed that TYL2,a high efficient strain was isolated and was identified as Brevibacillus borstelensis.The degradation rate of TYL by this strain could reach to 75%with an initial concentration of 25 mg L^-1 within 7 days under conditions of 7%B.borstelensis(v/v,2×108 CFU m L^-1)at p H 7.0 and at 35°C.It is interesting that this strain has a very strong ability to degrade the TYL in natural sewage with the degradation rate of 65%within 7 days.This result could be helpful for the degradation of TYL and provide guidance for the degradation of other antibiotics.展开更多
The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is inv...The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. The variations of Stark energy shift with electric field, impurity position, A1 component and areal electron density are discussed. Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states. For a given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. The weakening of the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field. Furthermore, the screening effect weakens the mixture crystal effect, thereby influencing the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.展开更多
[Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate i...[Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate isolation,and the ability of enzyme production was measured by filter paper and Folin-phenol method.The strain with the strongest ability of enzyme production was screened as a candidate strain,then the factors influencing the ability of enzyme production was studied,finally the conditions for enzyme production was optimized through orthogonal test.[Result] No.5 strain was screened as a candidate strain due to its strong ability of enzyme production(6.00 U/ml),which accounted for 134.1% of that of Bacillus licheniformis,and it was gram-positive bacterium belonging to Clostridium.Orthogonal test showed that the optimal condition for producing protease was an environment with pH=11,0.3% of sucrose and 0.8% of peptone in the fermentation medium,and inoculation amount was 105 cfu/ml.In addition,peptone had significant impact on the level of enzyme production.[Conclusion] The study could provide theoretical references for the screening of strains producing alkaline protease.展开更多
Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing...Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing method to fabricate the strain sensor based upon an electrical-resistance mechanism. After curing elastomeric polyurethane film with a thickness of 150 μm on PET film, the polyester resin mixed with blocked isocyanate curing agent was coated as a masking layer to reduce the film’s stickiness. The effect of the polyester masking layer upon the silver paste screen printing process was examined using a rolling-ball-tack test, TGA analysis of polyester resins, and cured silver-electrode films. The cost-effective strain sensor fabricated by using silver paste and screen printing processes on the stretchable-polyurethane-substrate film showed high sensitivity and fast response in a strain range of up to 100%.展开更多
[Objective] Strain Biok Av-023 used as the control was employed on screening of high-avermectin yield mutants by rational screening.[Method] With Biok Av-023 as the original strain,the positive mutation strain was fir...[Objective] Strain Biok Av-023 used as the control was employed on screening of high-avermectin yield mutants by rational screening.[Method] With Biok Av-023 as the original strain,the positive mutation strain was firstly screened by routine UV mutagenesis,and then the high-yield avermectin producing strain was selected by the breeding way inferred by L-Ile induction.[Result] UV mutation and L-Ile directional screening had showed that the best L-Ile screening concentration was 0.5%,and the high-yield mutation strain AV60s-32 after re-screening reached the highest titer of 4520 IU/ml,which increased by 23.4% compared with the original strain.[Conclusion] The production of avermectin can be effectively enhanced by the combined way of UV mutation and L-Ile rational breeding.展开更多
基金Supported by the Scientific Research Foundation for Middle-aged and Young Scientistof Qinghai University,China(2010-QN-06)~~
文摘The 46 strains that produced inulase were screened from rhizosphere soil where Jerusalem artichoke was planted in Qinghai.One strain with high inulinase productivity was obtained through further screening and the enzyme activity was6.67 U/ml.This inulinase was exonuclease.Through determination and analysis of the r DNA-ITS sequence,and analysis of morphology,the fungus was identified as Actinomucor elegans.
基金supported by the Agriculture Application Investigation and I mprovement Item of New Countryside Construction and Promotion Project of the Bureau of Science and Technology in Xi an(No.NC08005)
文摘Strains from the cellulose-containing environment were collected.Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium)and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium)indicated that five strains obtained were best suited for high performance cellulose degradation.Determination of sodium carboxymethylcellulose activity(CMCA)and filter paper activity(FPA)was accomplished for each of the five.The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF)and simultaneous saccharification and fermentation(SSF)respectively.
基金Supported by The Basic Ability Improvement Project for Young and Middle-aged Teachers in Guangxi Universities(2017KY0288)。
文摘[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to the traditional microbial culture method, with trans-anethole as the sole carbon source, through enrichment culture and separation and purification, preliminary screening by thin layer chromatography and re-screening by high-performance liquid chromatography, strains that degraded trans-anethole to produce anisic acid were obtained, and 16 S rDNA sequencing and phylogenetic tree construction were performed for genetic analysis. [Results] Eleven strains that degraded trans-anethole to produce anisic acid were obtained, among which strain NT2 that produced anisic acid with a relatively high efficiency was initially identified as Pseudomonas sp. The strain’s trans-anethole degradation rate was 45.41%, and the molar production rate and cumulative concentration of anisic acid were 21.80% and 1.96 g/L, respectively. [Conclusions] Strain NT2 has a strong ability to degrade trans-anethole to produce anisic acid, and can enrich strain resources for degradation of trans-anethole to anisic acid through microbial conversion.
文摘In this paper, eleven strains, which were screened strictly from raw royal jelly, soil andhoneycomb etc. by meansof dilution plate and spread plate methods, were cultured at 28℃ for 60 h with shaking. To determine whether they could yield10-Hydroxy-2-decenoic acid during fermentation, gas chromatography and gas chromatography-mass spectrometry methodswere used. The results showed that the strains BH002 and BH004, were both identified as Crytococcaceae, where BH002was primarily classified into Candida for possessing the abilities. The 10-HDA productivity of Candida BH002 and that ofBH004 were 0.327% and 0.2648% respectively.
基金jointly supported by the National Key R&D Program of China(2018YFD0500206)the National Natural Science Foundation of China(31772395)the Fundamental Research Funds for Central Non-profit Scientific Institution,Chinese Academy of Agricultural Sciences(1610132019046)。
文摘Antibiotics residues have been accumulating in the environment day by day due to overuse of antibiotics.Recalcitrant antibiotic residues,such as tylosin(TYL),can cause serious environmental problems,which makes it important to eliminate TYL from the environment.It is important to eliminate TYL from the environment.In this study,a strain was isolated and purified from fermentation by-product that came from a TYL production factory.The TYL degrading strain was identified by its morphology,physiological and biochemical reactions and sequencing the PCR-amplified fragments of its 16 S r DNAcoding genes.The temperature,shaking speed,initial TYL concentration,p H and inoculum sizes were investigated under simulated conditions by using single factor tests.The results showed that TYL2,a high efficient strain was isolated and was identified as Brevibacillus borstelensis.The degradation rate of TYL by this strain could reach to 75%with an initial concentration of 25 mg L^-1 within 7 days under conditions of 7%B.borstelensis(v/v,2×108 CFU m L^-1)at p H 7.0 and at 35°C.It is interesting that this strain has a very strong ability to degrade the TYL in natural sewage with the degradation rate of 65%within 7 days.This result could be helpful for the degradation of TYL and provide guidance for the degradation of other antibiotics.
基金Project supported by the National Natural Science Foundation of China (Grant No 60566002)the Specialized Research Fundfor the Doctoral Program of Higher Education of China (Grant No 20070126001)
文摘The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. The variations of Stark energy shift with electric field, impurity position, A1 component and areal electron density are discussed. Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states. For a given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. The weakening of the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field. Furthermore, the screening effect weakens the mixture crystal effect, thereby influencing the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.
基金Supported by National Natural Science Foundation of China(31070361)Beijing Outstanding Teaching Team Project about Ecology in 2008+2 种基金The Fundamental Research Funds for the Central Universities (0910KYZY43)Undergraduate Research and Training Project of Minzu University of China (URTP201011115)Quality Course Project of Minzu University of China in 2011
文摘[Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate isolation,and the ability of enzyme production was measured by filter paper and Folin-phenol method.The strain with the strongest ability of enzyme production was screened as a candidate strain,then the factors influencing the ability of enzyme production was studied,finally the conditions for enzyme production was optimized through orthogonal test.[Result] No.5 strain was screened as a candidate strain due to its strong ability of enzyme production(6.00 U/ml),which accounted for 134.1% of that of Bacillus licheniformis,and it was gram-positive bacterium belonging to Clostridium.Orthogonal test showed that the optimal condition for producing protease was an environment with pH=11,0.3% of sucrose and 0.8% of peptone in the fermentation medium,and inoculation amount was 105 cfu/ml.In addition,peptone had significant impact on the level of enzyme production.[Conclusion] The study could provide theoretical references for the screening of strains producing alkaline protease.
文摘Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing method to fabricate the strain sensor based upon an electrical-resistance mechanism. After curing elastomeric polyurethane film with a thickness of 150 μm on PET film, the polyester resin mixed with blocked isocyanate curing agent was coated as a masking layer to reduce the film’s stickiness. The effect of the polyester masking layer upon the silver paste screen printing process was examined using a rolling-ball-tack test, TGA analysis of polyester resins, and cured silver-electrode films. The cost-effective strain sensor fabricated by using silver paste and screen printing processes on the stretchable-polyurethane-substrate film showed high sensitivity and fast response in a strain range of up to 100%.
基金Supported by 863 Project (2009AA032904 )Scientific ResearchStarting-up Project for Young Teachers in Changshu Institute oTechnology" Hundreds of Entrepreneurs into Campus" Project inChangshu Institute of Technology~~
文摘[Objective] Strain Biok Av-023 used as the control was employed on screening of high-avermectin yield mutants by rational screening.[Method] With Biok Av-023 as the original strain,the positive mutation strain was firstly screened by routine UV mutagenesis,and then the high-yield avermectin producing strain was selected by the breeding way inferred by L-Ile induction.[Result] UV mutation and L-Ile directional screening had showed that the best L-Ile screening concentration was 0.5%,and the high-yield mutation strain AV60s-32 after re-screening reached the highest titer of 4520 IU/ml,which increased by 23.4% compared with the original strain.[Conclusion] The production of avermectin can be effectively enhanced by the combined way of UV mutation and L-Ile rational breeding.
