原生质体紫外诱变选育木聚糖酶高产菌株

Screening of high yield xylanase mutants by protoplast UV-mutagenesis

采用紫外诱变选育木聚糖酶高产菌株，通过对出发菌株Thermomyces lanuginosus DSM10635原生质体形成条件及诱变条件的研究，探索出了其原生质体形成的最适条件：酶系及酶解浓度为0．010g／mL纤维素酶＋0．010g／mL蜗牛酶（体积比1：1混合），菌龄58h，酶解时间2．5h，酶解温度30℃～34℃，稳渗剂为0．6mol／L的甘露醇；紫外诱变的最佳条件：距离15W紫外灯30cm处，照射时间5min，通过初筛和复筛，最终选育出3株遗传性能稳定的木聚糖酶高产诱变株，木聚糖酶的酶活分别提高了26．5％、37．78％、28．2％。

High xylanase yield mutants were screened with treatment with UV-mutagenesis. According to the study of formation of protoplasts of starting strain Thermomyces lanuginosus DSM10635 and conditions ofmutagenesis, optimum conditions for protoplast formation were determined as follows, cellulase 0.010g/ml and helicase 0.010g/ml mixed with volume ratio 1：1, hypha age 58h, enzymatic hydrolysis for 2.5h under 30℃-34℃, osmotic stabilizer 0.6mol/L mannitol; optimum UV mutagenesis was 30 cm department, with a 15W UV light, treated for 5min. After primary and secondary screening, three high yield xylanase mutants were obtained, whose activity of xylanase improved 26.5%, 37.78% and 28.2%, respectively.