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
Inulinase is an enzyme catalyzing the hydrolysis of inulin, a plant reserve polysaccharide, into fructoses and fructooligosaccharides which are widely used as food additives. Here we report inulinase from a newly isol...Inulinase is an enzyme catalyzing the hydrolysis of inulin, a plant reserve polysaccharide, into fructoses and fructooligosaccharides which are widely used as food additives. Here we report inulinase from a newly isolated Streptomyces as in the past decade there have been very few reports on inulinases from Streptomyces, especially purification and characterization of these enzymes. Out of 371 Streptomyces isolates, Streptomyces sp. CP01 produced highest inulinase activity of 0.50 U/ml. The enzyme activity was increased to 1.60 U/ml when CP01 was cultivated under the optimal conditions which consisted of using basal medium (Czapek’s Dox) containing 1% (w/v) inulin extract from Jerusalem artichoke’s root tubers and 0.7% (w/v) tryptone at pH8, shaking at 200 rpm and 28℃ for 24 h. The enzyme was purified from culture filtrate to about 67-fold purity by (NH4)2SO4 precipitation followed by four consecutive column chromatography steps. The purified enzyme is a single peptide with approximate molecular mass of 73 kDa as analyzed by gel filtration and 70.8 kDa as assessed by SDS-PAGE. The enzyme is optimally active at 55℃ and pH 6.0, however it still possesses more than 80% of the maximal activity at pH ranging from 5.5 to 9.0. It is stable at temperature up to 50℃ and at broad range of pH from 5.0 to 9.0 for 30 min. Its Km and Vmax values for inulin were 2.34 mM and 440 μmolmin–1mg–1, respectively. This enzyme has potential for industrial application as it is active at moderately high temperature and wide range of pH.展开更多
A Plackett-Burman design was employed for screening 18 nutrient components for the production of inulinase using streptomyces sp.and pressmud as the substrate via solid-state fermentation(SSF).From the experiments,thr...A Plackett-Burman design was employed for screening 18 nutrient components for the production of inulinase using streptomyces sp.and pressmud as the substrate via solid-state fermentation(SSF).From the experiments,three nutrients viz.yeast extract,FeSO_(4)·7H_(2)O,and NH4NO3 were found to be the most significant components.Hence these three components were selected and optimized using Response Surface Methodology(RSM).The optimum conditions are:yeast extract 0.00274 g/gds,FeSO_(4)·7H_(2)O 0.00011 g/gds and NH4NO30.00772 g/gds.The effect of the substrate concentration and initial moisture content were also studied.A substrate concentration of 12 g and an initial moisture content of 65%are optimum for the maximum production of inulinase(89 U/gds).展开更多
A total of 328 yeast strains from seawater, sediments, mud of salterns, the guts of marine fish and marine algae were obtained. The results of routine identification and molecular methods show that five yeast strains ...A total of 328 yeast strains from seawater, sediments, mud of salterns, the guts of marine fish and marine algae were obtained. The results of routine identification and molecular methods show that five yeast strains obtained in this study belonged to Pichia spp., including Pichia guilliermondii 1 uv-small, Pichia ohmeri YF04d, Pichia fermentans YF12b, Pichia burtonii YF11A and Pichia anomala YF07b. Further studies revealed that Pichia anomala YF07b could produce killer toxin against pathogenic yeasts in crabs while Pichia guilliermondii luv-small could produce high activity of extracellular inulinase. It is advisable to test if Pichia ohmeri YF04d obtained in this study is related to central-venous-catheter-associated infection.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.
文摘Inulinase is an enzyme catalyzing the hydrolysis of inulin, a plant reserve polysaccharide, into fructoses and fructooligosaccharides which are widely used as food additives. Here we report inulinase from a newly isolated Streptomyces as in the past decade there have been very few reports on inulinases from Streptomyces, especially purification and characterization of these enzymes. Out of 371 Streptomyces isolates, Streptomyces sp. CP01 produced highest inulinase activity of 0.50 U/ml. The enzyme activity was increased to 1.60 U/ml when CP01 was cultivated under the optimal conditions which consisted of using basal medium (Czapek’s Dox) containing 1% (w/v) inulin extract from Jerusalem artichoke’s root tubers and 0.7% (w/v) tryptone at pH8, shaking at 200 rpm and 28℃ for 24 h. The enzyme was purified from culture filtrate to about 67-fold purity by (NH4)2SO4 precipitation followed by four consecutive column chromatography steps. The purified enzyme is a single peptide with approximate molecular mass of 73 kDa as analyzed by gel filtration and 70.8 kDa as assessed by SDS-PAGE. The enzyme is optimally active at 55℃ and pH 6.0, however it still possesses more than 80% of the maximal activity at pH ranging from 5.5 to 9.0. It is stable at temperature up to 50℃ and at broad range of pH from 5.0 to 9.0 for 30 min. Its Km and Vmax values for inulin were 2.34 mM and 440 μmolmin–1mg–1, respectively. This enzyme has potential for industrial application as it is active at moderately high temperature and wide range of pH.
文摘A Plackett-Burman design was employed for screening 18 nutrient components for the production of inulinase using streptomyces sp.and pressmud as the substrate via solid-state fermentation(SSF).From the experiments,three nutrients viz.yeast extract,FeSO_(4)·7H_(2)O,and NH4NO3 were found to be the most significant components.Hence these three components were selected and optimized using Response Surface Methodology(RSM).The optimum conditions are:yeast extract 0.00274 g/gds,FeSO_(4)·7H_(2)O 0.00011 g/gds and NH4NO30.00772 g/gds.The effect of the substrate concentration and initial moisture content were also studied.A substrate concentration of 12 g and an initial moisture content of 65%are optimum for the maximum production of inulinase(89 U/gds).
文摘A total of 328 yeast strains from seawater, sediments, mud of salterns, the guts of marine fish and marine algae were obtained. The results of routine identification and molecular methods show that five yeast strains obtained in this study belonged to Pichia spp., including Pichia guilliermondii 1 uv-small, Pichia ohmeri YF04d, Pichia fermentans YF12b, Pichia burtonii YF11A and Pichia anomala YF07b. Further studies revealed that Pichia anomala YF07b could produce killer toxin against pathogenic yeasts in crabs while Pichia guilliermondii luv-small could produce high activity of extracellular inulinase. It is advisable to test if Pichia ohmeri YF04d obtained in this study is related to central-venous-catheter-associated infection.
