一株降解纤维素的高温放线菌的筛选及其产酶条件研究

Screening of a Cellulose-Decomposing Thermoactinomyces Strain and Its Enzyme-Producing Conditions

从高温稻草堆肥中分离到一株能降解纤维素的高温放线菌CN9,经初步鉴定该菌株属Streptomycessp.,进一步对其产羧甲基纤维素酶(CMCase)的条件进行了研究。结果表明,该菌株产CMCase的最佳碳源为麸皮,最佳氮源为大豆粉,最佳金属离子为Ca2+,最适培养条件为45℃、250 r.min-1、培养5 d。以麸皮、大豆粉、Ca2+及摇床温度4因素进行正交实验结果表明,麸皮10 g.L-1、大豆粉4 g.L-1、Ca2+0.4 g.L-1及摇床温度45℃为产CMCase最佳条件,此条件下CMCase活力为11.52 U.g-1。

By the method of the size of clear zones on the cellulose Congo red medium and filter paper weightlessness , a cellulose - decompsing thermoactinomyces strain CN9 was isolated from high temperature straw compost. It was found that it belongs to Streptomyces sp. Its conditions of producing CMCase was studied. The results showed that the best conditions were bran as carbon source, soybean meal as nitrogen source, Ca^2＋ as metallic ion. The optimum conditions were： enzyme-producing at 45 ℃ and shaking at 250 r · min^-1, enzyme-producing at the fifth day. The four-factor of bran, soybean meal, Ca^2＋ and shaking -table was studied by the orthogonal experiment. The results indicated that the best conditions of producing CMCase were bran 10 g · L^-1 , soybean meal 4 g · L^-1 , Ca^2＋0.4 g · L^-1 and shaking at45℃. And the enzyme activity reached 11.52 U · g^-1 under this condition.