新分离菌Streptomyces产小分子CMC液化酶的研究

CMC-LIQUEFYING ENZYME WITH LOW MOLECULAR WEIGHT FROM NEWLY ISOLATED STREPTOMYCES

新分离纤维素分解菌经鉴定为链霉菌属中的新种，暂定名为ＳｔｒｅｐｔｏｍｙｃｅｓｓｐＬＸ，革兰氏阳性，产气生孢子，好氧生长，最适生长温度和ＰＨ为３０℃和７．２。该菌能够完全降解纤维素且不产生还原糖，并分泌一种分子量为９．２ｋｕ的液化性质的内切纤维素液化酶，亦即ＣＭＣ液化酶，该酶在裂解滤纸为短纤维的过程中既没有还原糖生成，也没有失重现象发生，而且纤维素的聚合度也几乎没有明显变化，推测可能是一种能打开氢键的小分子解链酶。

A new bacterium,Streptomyces sp.LX,was isolated from soil, which was aerobicGrampositive and could decompose crystalline cellulose completely while only a trace of reducing sugarwere found in cultures over the incubation when grown on cellulosic materials.The growth temperatureand PH optima of which were 30aC and 7.2 Streptongces sp.LX was found to be inducible for extracellularendo-cellulase with CMC-liquefying activity(CMC-liquefying enzyme).The molecular weight of which is 9.2ku.It was found no detectable reducing sugar released and little weight loss over the fragmentation of filter paper,moreover,there was no significant change in the degree of polymerization of cellulose.Presumably it may be achain-opening enzyme capable of disturbing to intra or inter china hydrogen bonds.