【摘要】 炭黑曲霉（Aspergillus carbonarius）AS 3.396经亚硝基胍和 Co⁶⁰γ-射线诱变,获得一株高产果胶酶突变株 G5512。该菌株的发酵滤液,以高酯果胶为底物的酶活力为860u/ml;以低酯果胶为底物的酶活力为1227u/ml。产酶活力水平约为原出发菌株的2—6倍。产酶最适培养条件为:起始 pH4.0—4.5,30℃,72—90小时。酶作用最适条件为:高酯果胶为底物时,pH3.5,50℃;低酯果胶为底物时,pH4.5,50℃。pH 稳定范围为2.0—6.5（高酯果胶）和4.5—5.0（低酯果胶）。酶在60℃保温15分钟,高酯果胶为底物的酶剩余活力71%,低酯果胶为底物的酶活力仅剩余1%。更多还原

【Abstract】 A mutant strain G5512 with high yield of pectinase was obtained from Aspergillus carbonarius AS 3.396 by chemical mutation using N-methyl-N′-nitro-N-nitro-soguanidine（MNNG）and treatment with Co⁶⁰ radiation.The enzyme activities of fermentation brothwere 860u/ml for high-ester pectin and 1227u/ml for low-ester pectin.The activitieswere about 2—6 times of the original strain’s.The optimal culture conditions were found:initial pH 4.0—4.5 at 30℃ for 72—90h.The optimal conditions for enzyme catalysis were pH 3.5 at 50℃ for high-ester pectinand pH 4.5 at 50℃ for low-ester pectin respectively.The enzyme showed a wide stabilitybetween pH 2.0 and 6.5 at 30℃ for 12h.（high-ester pectin）and a narrow pH stabilitybetween 4.5 and 5.0 at 30℃ for 12h（low-ester pectin）.After incubation at 60℃ for 15min,enzyme kept 71% activity for high-ester pectin,and only 1% activity for low-esterpectin.更多还原