巨大芽孢杆菌BP931胞外青霉素G酰化酶的产生条件

STUDIES ON PRODUCTION CONDITIONS FOR EXTRACELLULAR PENICILLIN G ACYLASE FROM BACILLUS MEGATERIUM BP931

研究了巨大芽孢杆菌(Bacillus megaterium)BP 931胞外青霉素G酰化酶的产生条件。菌在由葡萄糖0.7％,氮源1号0.5％,酵母膏1.0％和苯乙酸0.8％组成的液体培养基(灭菌前pH9.0,灭菌后pH8.0)中,28℃振荡培养44h。以6-硝基-3-苯乙酰胺基苯甲酸为底物,培养滤液酶活力为9.0IU/ml。诱导物苯乙酸于培养6h后加入,酶活力可以提高到11.0IU/ml。Ca^(2+)、Al^(3+)、Sn^(4+)、Mn^(2+)和Fe^(2+)离子降低酶的形成;Cu^+和C0^(2+)离子显著抑制菌生长,降低酶的形成;Zn^(2+),Cd^(2+)和Hg^(2+)离子完全抑制菌生长和酶形成。

Production conditions for extracellular penicillin G acylase from Bacillus megaterium BP 931 were studied. Liquid seed was prepared by cultivating the strain in liquid medium consisted of 0.7% glucose, 0.5% nitrogen source No.l, 1.0% yeast extract at pH 7.5 and 28℃ for 16h. Fermentation was conducted in 250ml flasks, each containing 20ml of medium consisted of 0.7% glucose, 0.5% nitrogen source No.l, 1.0% yeast extract and 0.8% phenylacetic acid (Na+salt). The optimal culture conditions are following: 5% inoculum size, temperature 28℃ , 250r/ min and cultivation time 44h. Enzyme activity toward 0.0643% 6-nitro-3-phenylacetarnido-benzonic acid at pH 7.7 and 37℃ for 10 min was 9.0 IU per ml the culture filtrate per min. When inducer, phenylacetic acid, was added after 6h of cultivation, enzyme activity was enhanced to 11.0 IU/ ml. Enzyme formation was decreased by Ca2+, A13+, Sn4+, Mn2+, Fe2+, Cu+, Co2+and strongly inhibited by Zn2+, Cd2+and Hg2+.