| A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye),microorganisms and human life are inseparable.There are only 1% of them can be curtured in the laboratory,it makes people have the huge resources of great interest for the other 99%.Metagenome is a very important method for finding the resouce.Metagenomic analysis involves isolating DNA from an environmental sample, cloning the DNA into a suitable vector,transforming the clones into a host bacterium, and screening the resulting transformants.In this reserch,we use the existing Genomic library,the 50 clones found in the library were analysed by the 454-pyrosequencing technology:1.Genomic DNA extraction from Hunan hot spring,preparing for the library constract;2.Cloning and expression the cellulose,alpha amylase,peptidase,xylanase,glucan 1,3-beta-glucosidase,glucosylcera midaseand esterase genes from the bac libraby.3. Purification of extracellularβ-1-1,3-glucosidase performed by HPLC.4. Thisβ-glucanase activity was associated with a glycosylated 40-kDa protein.it had an optimum pH of 7.0 and an optimum temperature of 60℃.The glucosidase in this study had good thermostability at 30-70℃and good pH stability at pH6-8.A substrate kinetic study gave a Km value of 4.517mg/L for soluble (laminarin).Significant increase in lipolytic activity was observed with addition of Ba2+ and Ca2+, while decrease with Cu2+ and Zn2+... |
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