Solid-state fermentation was carried out using mycelium powder of <em>Aspergillus niger</em> as substrate for the production of chitosanase of <em>Streptomyces</em>. Results of the experiments ...Solid-state fermentation was carried out using mycelium powder of <em>Aspergillus niger</em> as substrate for the production of chitosanase of <em>Streptomyces</em>. Results of the experiments indicated that the optimal medium consisted of wheat bran and mycelium powder of <em>Aspergillus niger</em> with initial moisture content of 60% - 70%. The enzyme activity reached 41.33 U per gram dry medium after cultured for 5 days at 28<span style="white-space:nowrap;">°</span>C - 30<span style="white-space:nowrap;">°</span>C and an initial pH 6.5. Chitosanase was detected on the second day of incubation and had maximal activity at 5 days and decreased gradually within a 1 month period. Solid-state fermentation is maybe an economic alternative in the production.展开更多
Chitosanases EAG1 is a classical glycoside hydrolase from Bacillus ehimensis. The previous researches showed that this Chitosanases can not only hydrolyze the b1,4-glycosidic bonds of chitosan to COS in different size...Chitosanases EAG1 is a classical glycoside hydrolase from Bacillus ehimensis. The previous researches showed that this Chitosanases can not only hydrolyze the b1,4-glycosidic bonds of chitosan to COS in different sizes but also keep a high catalytic activity in organic, which was useful for producing chitooligosaccharides and GlcN for use in the food and pharmacological industries. While it is instable in the liquid state. This shortcoming seriously restricts its industrial application. Here we used the modeled structure of EAG1 and the molecular modeling software package to screen the free chemical database ZINC. Moreover, the strategies including “initial filter” and consensus scoring were applied to accelerate the process and improve the success rate of virtual screening. Finally, five compounds were screened and they were purchased or synthetized to test their binding affinity against EAG1. The test results showed that one of them could inhibit the enzyme with an apparent Ki of 1.5 μM. The result may take the foundation for further inhibitor screening and design against EAG1 and the screened compound may also help to improve the liquid stability of EAG1 and expand its industrial application.展开更多
文摘Solid-state fermentation was carried out using mycelium powder of <em>Aspergillus niger</em> as substrate for the production of chitosanase of <em>Streptomyces</em>. Results of the experiments indicated that the optimal medium consisted of wheat bran and mycelium powder of <em>Aspergillus niger</em> with initial moisture content of 60% - 70%. The enzyme activity reached 41.33 U per gram dry medium after cultured for 5 days at 28<span style="white-space:nowrap;">°</span>C - 30<span style="white-space:nowrap;">°</span>C and an initial pH 6.5. Chitosanase was detected on the second day of incubation and had maximal activity at 5 days and decreased gradually within a 1 month period. Solid-state fermentation is maybe an economic alternative in the production.
文摘Chitosanases EAG1 is a classical glycoside hydrolase from Bacillus ehimensis. The previous researches showed that this Chitosanases can not only hydrolyze the b1,4-glycosidic bonds of chitosan to COS in different sizes but also keep a high catalytic activity in organic, which was useful for producing chitooligosaccharides and GlcN for use in the food and pharmacological industries. While it is instable in the liquid state. This shortcoming seriously restricts its industrial application. Here we used the modeled structure of EAG1 and the molecular modeling software package to screen the free chemical database ZINC. Moreover, the strategies including “initial filter” and consensus scoring were applied to accelerate the process and improve the success rate of virtual screening. Finally, five compounds were screened and they were purchased or synthetized to test their binding affinity against EAG1. The test results showed that one of them could inhibit the enzyme with an apparent Ki of 1.5 μM. The result may take the foundation for further inhibitor screening and design against EAG1 and the screened compound may also help to improve the liquid stability of EAG1 and expand its industrial application.
