Isolation and Identification of Thermophilic Protease Bacterium 0701 and its Protease Characterization

Abstract

Soil was collected from Huguangyan of Zhanjiang city and regarded as separate material, It was screened thermophilic protease-producing bacteria though dilution flat, transparent circle and Folin method. Strain 0701 isolated was identificated by its morphological features, physiological and biochemical characteristics and 16s rRNA. This experiment also researched on the genetic stability of enzyme producing, and different temperature, pH influence on proteases activity. 25 high temperature-tolerance protease producing strains were isolated, which accounted for 28.1 % of all the isolated strains. Among them, strain 0701 proteases activity was 247 U/mL and it was far higher than that of proteases for other strains and the most optimum reaction temperature and pH of the proteases were 70oC and pH 7.0, respectively, and retained high enzyme activity within 50-80 oC, pH6.5-9.0. The strain 0703 still had the ability to produce protease after consecutive 4 generation, and was identified as Bacillus subtilis by morphological, physiological-biochemical characteristics and 16s rRNA.