纤维素降解菌Aspergillus sp. YN1的产酶条件及酶学特性

从牛羊粪堆肥中筛选出一株纤维素降解菌Aspergillus sp.YN1,主要研究了液体发酵培养基中碳源、氮源、培养温度、起始pH、通气量以及接种菌龄对菌株YN1的羧甲基纤维素酶活(CMC酶活)及滤纸酶活的影响。研究结果表明,在优化条件下,该菌的CMC酶活、滤纸酶活在培养第3天分别达到0.53U/mL和0.15U/mL。在酶学特性研究中,菌株YN1的CMC酶的最适反应温度为70°C,最适反应pH4.0(酶促反应为30min)。用不同温度处理1h或不同pH处理2h,YN1的CMC酶在30°C?50°C或pH3.0?4.0之间仍可保持80%以上的酶活性,对热及酸表现出较高的稳定性。

The Enzyme-producing Conditions and Characteristics of Cellulases of a Cellulose-decomposing Strain YN1

Aspergillus sp. YN1, with cellulase activity, was screened from sheep and cattles feces compost. Different conditions for liquid fermentation which including carbon source, nitrogen source, temperature, pH, capacity of oxygen and inoculum age for the production of cellulases had been studied. The CMCase activity was 0.53 U/mL and the Filter-Paper activity was 0.15 U/mL when YN1 was cultured in the optimized condition for 3 d. In the study of characteristics of cellulases, the optimal reaction temperature was at 70°C and the optimal reaction pH was at 4.0 (in a 30-min reaction period). The cellulase activity retained above 80% when the celluases were treated under the conditions that the temperature was from 30°C to 50°C for 1 h or the pH from 3.0 to 4.0 for 2 h, which showed the celluases produced by YN1 have resistance to heat and acid.