Study On The Screening And Enzymetic Properties Of A Novel Cold-active Amylase-producing Strain

The paper gatherd low temperature soil samples and screened Cold temperature-amylase -microorganisms to gain the question of emylase's originate.A novel cold-active amylase-producing strain was screened and isolated from qinghe and fuyun in xinjiang.The strain was identified as bacillus by morphologic characteristics. We called it LA77( Aeromonas media). The amylase was concentrated from supernatant of strain culture. The optimum temperature and pH for it were 30℃and 6.0. It was stable temperature in 30℃and 40℃for half an hour and was worse thermostable, which remained 80% and 18% of enzyme activity. In addition ,the amylase is stimulated in the presence of Ca2+,K+, but is inhibited by Cu2+,Hg2+ .Through nutritional lab we gained that carbon source1%,nrtiogen source 2%,the rotational speed 200r/min,liquid volume100ml/500ml is the optimum nutritional conditions.The larger emylase activity is 23.83u/ml.Cold-active amylas which is extracellula in incubation period of LA77 can be purified by salt out .The molecular weight of the purified cold-active amylase-is 52.71KD and Km is 1.27mg/ml,Vmax is 1794umol/(min?ml). All these show that there are large seimilla and have a big potential in application of cold-active amylase.