pH值对3个根霉菌株产酶活性的影响

Enzyme-producing Abilities of Three Rhizopus Strains at Different pH Levels

在不同的pH值培养基中培养ERh1123、ERh3421、ERh5131 3个根霉菌株,研究其产酶的pH条件,同时将得到的酶液在不同的pH值条件下与一定的底物反应,分别测定了糖化酶、液化酶、蛋白酶活性,研究了pH条件对产酶活性的影响。结果表明:菌株产糖化酶、液化酶的适宜pH为4.6～5.2,在此条件下,糖化酶的活性为1.41×102～1.59×102U/g,液化酶的活性为0.69×103～2.21×103U/g,菌株产蛋白酶的适宜pH为5.8,其活性为1.98×103U/g～2.58×102U/g;反应时糖化酶适宜的pH为4.6,蛋白酶适宜的pH为5.8,液化酶适宜的pH为5.2-5.8,反应时酶的活性与产酶条件下相比,前两种酶的活性可分别提高到1.52×102～3.21×102U/g,2.56×102～2.97×102U/g,但液化酶的活性没有增加.总体来看,在根霉菌株产酶及酶反应时提供适宜的pH值条件对酶活性的提高具有很大的促进作用.

The pH reaction conditions for enzyme-producing of three Rhizopus of ERh1123,ERh3421 and ERh5131,which was cultivated in culture medium with different pH value,and the activeness level of saccharified enzyme,liquefied enzyme and protease achived from aboved culture medium have been respectively measured in reactions with certain substrates,and analysed the influence of enzyme-producing by pH value.The study shows that,at optimal culture medium of pH value of 4.6～5.2,the activeness of saccharified enzymes produced by above strains can be reached at level of 1.41×102～1.59×102U/g,and liquefied enzymes 0.69×103～2.21×103U/g;and for protease the activeness can reach 1.98×103U/g ～2.58×102 U/g in culture medium with 5.8 of pH value;in reaction with certain substrates,the optimal level of pH value for saccharified enzyme was 4.6,protease 5.8,liquefied enzyme 5.2～5.8,and the activeness of enzyme of the former two,in contrast to that at condition of enzyme-producing,can be respectively improved to 1.52×102～3.21×102U/g and 2.56×102～2.97×102U/g,but no change for liquefied enzyme.Generally,there exists considerable improving for enzyme activeness levels by pH value of culture medium and of reaction liquied with substrates.