紫外-亚硝酸钠复合诱变高产纤维素酶菌株

为得到高产纤维素酶的菌株，改善菌种产纤维素酶的能力，该研究以贝莱斯芽孢杆菌（Bacillus velezensis）为原始菌株，以纤维素酶酶活为考察指标，通过单因素和正交试验优化复合诱变条件。结果表明，最优复合诱变条件为紫外（UV）处理150 s、0.25 mol/L亚硝酸钠（NaNO2）在诱变温度23 ℃下诱变处理23 min。在此优化复合诱变条件下，突变株UN-5纤维素酶酶活为101.48 U/mL，比原始菌株的酶活提高了205.8%。经10代传代，纤维素酶酶活仍有100.5 U/mL，说明该突变株产纤维素酶能力强且遗传性状稳定。

Ultraviolet-NaNO2 complex mutagenesis of high-yield cellulase strain

In order to obtain a high-yield cellulase strain and improve the cellulase-producing ability of the strain, using Bacillus velezensis as the original strain and the cellulase activity as the index, the complex mutagenesis conditions were optimized by single factor and orthogonal tests. The results showed that the optimal complex mutagenesis conditions were ultraviolet (UV) treatment for 150 s, and NaNO2 0.25 mol/L mutagenesis at temperature 23 ℃ for 23 min. Under the optimal mutagenesis conditions, the cellulase activity of the mutant strain UN-5 was 101.48 U/ml, and the enzyme activity of the original strain was increased by 205.8%. After 10 generations, the cellulase activity was still 100.5 U/ml indicating that the mutant strain had strong cellulase production ability and stable genetic traits.