家白蚁中肠具有内切葡聚糖酶活性菌株的分离和鉴定

从家白蚁中肠分离得到了一株具有内切β-1,4-葡聚糖酶活性的细菌Streptomyces sp.Cf1,并经过16S rRNA和形态分析确定为属于链霉菌属(Streptomyces)一种.该菌具有内切β-1,4-葡聚糖酶活性但不具有糖苷酶活性.该菌所分泌的内切β-1,4-葡聚糖酶活性最大可达8.25 U/mg.菌株分泌酶活性的最适pH值为6～7,最适温度为60℃.从家白蚁中肠分离得到这一具内切葡聚糖酶活性的菌株表明,家白蚁中肠细菌可以通过分泌内切葡聚糖酶与白蚁内源性内切葡聚糖酶一道参与食物中纤维素的降解.

Identification and isolation of a bacterium with endoglucanase activity from the midgut of the oriental termite,Coptotermes formosanus

A bacterium Streptomyces sp.Cfl was isolated from the midgut of C.formosanus.The identity of the bacterium was confirmed by 16S rRNA analysis and morphological characterization.The identified bacterium possessed endo - β - 1,4 - glucanase activity,but did not have β - glucosidases activity.Highest activities of endo - β - 1,4 - glucanas secreted by Streptomyces sp.Cfl reached to 8.25 U/mg.The optimal pH for the endoglucanases activity of the bacteriuml strain was between 6 and 7 and the optimal temperature for the enzyme secretion was 60℃.The finding of the bacterium in the midgut of C.formosanus suggests that midgut bacterium can produce secretory endoglucanases,which may cooperate with endogenous endoglucanases of the host to degrade cellulose of the ingested food.