产植酸酶菌株的筛选、诱变及酶学性质初探

从富含有机质的环境中采集土样,通过植酸钙平板透明圈法初筛和维生素C-硫酸-钼酸铵-酒石酸锑钾法测定植酸酶酶活复筛,共筛选到5株产植酸酶的霉菌,对这5株菌株进行紫外线和亚硝基胍复合诱变处理,最终获得一株高产植酸酶突变株NTG-506,酶活达到112 U/mL,比原始出发菌株的酶活提高了3.2倍.突变株NTG-506在250mL三角瓶中发酵培养,在装液量60 mL,接种量2%时,培养4 d后酶活达到最高,为124.5 U/mL.植酸酶的最适反应温度35℃,经50℃处理10 min后剩余酶活为原来的57%.

Screening,Mutagenesis and Enzymatic Properties of a Phytase Producing Strain

Five phytase producing fungous strains are obtained from organic matter rich soil samples using calcium phytate tablet transparent circle method for initial screen and vitamin C-sulfate ammonium molybdate-antimony potassium tartrate method for phytase activity determination. Mutagenesis of these five strains is carried out using UV combined with NTG treatment. A high phytase yielding mutant, NTG-506, is obtained. The phytase activity of this mutant strain reaches 112 U/mL, which is 3.2 times higher than than that of the wild strain. The mutant is fermented in a 250 mL flask with a liquid volume of 60 mL and the inoculum of 2%. The activity reaches itg peak （ 124. 5 U/mL） after 4 days of culture. The optimum temperature of the crude enzyme is 35 ℃, with 57% of residual activity after been kept at 50 ℃ for 10 min.