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1.
World J Microbiol Biotechnol ; 35(9): 135, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432264

RESUMO

The feather-degrading strain Thermoactinomyces sp. YT06 secretes an extracellular keratinolytic protease (KERTYT); however, the gene encoding this protease remains unknown. The kerT1 gene (1170 bp) encoding keratinase was cloned and expressed in Escherichia coli BL21(DE3). Purified recombinant keratinase (rKERTYT) was achieved at a yield of 39.16% and 65.27-fold purification with a specific activity of 1325 U/mg. It was shown that rKERTYT has many similarities to the native enzyme (KERTYT) by characterization of rKERTYT. The molecular weight of rKERTYT secreted by recombinant E. coli was approximately 28 kDa. The optimal temperature and the pH values of rKERTYT were 65 °C and 8.5, respectively, and the protein remained stable from 50 to 60 °C and pH 6-11. The keratinase was strongly inhibited by phenyl methane sulfonyl fluoride (PMSF), suggesting that it belongs to the serine protease family. It was significantly activated by Mn2+ and ß-mercaptoethanol (ß-Me). rKERTYT showed stability and retained over 80% activity with the existence of organic solvents such as acetone, methylbenzene and dimethyl sulfoxide. These findings indicated that rKERTYT will be a promising candidate for the enzymatic processing of keratinous wastes.


Assuntos
Clonagem Molecular , Escherichia coli/metabolismo , Expressão Gênica , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Thermoactinomyces/enzimologia , Ativadores de Enzimas/análise , Inibidores Enzimáticos/análise , Estabilidade Enzimática , Escherichia coli/genética , Concentração de Íons de Hidrogênio , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Temperatura Ambiente , Thermoactinomyces/genética
2.
J Ind Microbiol Biotechnol ; 43(9): 1249-60, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27337959

RESUMO

Rice straw (RS) is an important raw material for the preparation of Agaricus bisporus compost in China. In this study, the characterization of composting process from RS and wheat straw (WS) was compared for mushroom production. The results showed that the temperature in RS compost increased rapidly compared with WS compost, and the carbon (C)/nitrogen (N) ratio decreased quickly. The microbial changes during the Phase I and Phase II composting process were monitored using denaturing gradient gel electrophoresis (DGGE) and phospholipid fatty acid (PLFA) analysis. Bacteria were the dominant species during the process of composting and the bacterial community structure dramatically changed during heap composting according to the DGGE results. The bacterial community diversity of RS compost was abundant compared with WS compost at stages 4-5, but no distinct difference was observed after the controlled tunnel Phase II process. The total amount of PLFAs of RS compost, as an indicator of microbial biomass, was higher than that of WS. Clustering by DGGE and principal component analysis of the PLFA compositions revealed that there were differences in both the microbial population and community structure between RS- and WS-based composts. Our data indicated that composting of RS resulted in improved degradation and assimilation of breakdown products by A. bisporus, and suggested that the RS compost was effective for sustaining A. bisporus mushroom growth as well as conventional WS compost.


Assuntos
Agaricus/crescimento & desenvolvimento , Microbiologia do Solo , Bactérias/química , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Carbono/análise , Eletroforese em Gel de Gradiente Desnaturante , Ácidos Graxos/análise , Nitrogênio/análise , Oryza , Fosfolipídeos/química , Solo/química , Temperatura Ambiente , Triticum
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