一株具木聚糖酶活链霉菌的鉴定及其木聚糖降解酶系分析  

Identification of a Strain of Streptomyces and its Xylanolytic Enzyme System

作　　者：彭汀汀[1] 董宏平[1] 彭惠[1] 裴建军[1] 邵蔚蓝[1] 

机构地区：[1]南京师范大学生命科学学院,江苏南京210097

出　　处：《南京师大学报（自然科学版）》2006年第4期73-78,共6页Journal of Nanjing Normal University(Natural Science Edition)

摘　　要：分离得到一株具木聚糖酶活性的放线菌菌株pp2,该菌株具有典型链霉菌属的形态学特征.通过对其进行形态学、生理生化特性以及16SrRNA基因序列等方面的分类学研究,菌株pp2初步鉴定为链霉菌属的一个潜在新种.通过对菌株pp2的酶系研究发现该菌株胞外发酵液具木聚糖酶活性,细胞破碎液中具α-L-阿拉伯糖苷酶活性和β-D-木糖苷酶活性.其中木聚糖酶酶活力为30·3U/mg,酶反应最适温度为65℃,最适pH为5·4;37℃下稳定性很好,60℃下酶活性衰减很快.α-L-阿拉伯糖苷酶酶活力为1·81U/mg,酶反应最适温度为55℃,最适pH为6·0,55℃下稳定性能很好.β-D-木糖苷酶酶活力为0·04U/mg.A new actinomycete strain with the activity of xylanases, designated pp2, is isolated from Nanjing soil. Cultural characteristic studies strongly suggest that this strain belongs to the genus Streptomyces. The nucleotide sequence of the 16S rRNA gene （ 1 545 bp） of Streptomyees sp. strain pp2 exhibits close similarity （97% -99% ） with other Streptomyces 16S rRNA genes. The study shows that this strain also produces α-L-arabinosidase and β-D-xylosidase. Xylanase activity is found in the extra-cellular proteins, and α-L-arabinosidase and β-D-xylosidase activities are detected in the cell - free extract, while no acetyl xylan esterase, α-glucuronidase activities or phytase is detected in both solutions. The activity of xylanase is 30.3 U/rag, α-L-arabinosidase is 1.81 U/rag, and β-D-Xylosidase is 0.04 U/rag. The xylanase has optimal activity at 65 ℃ , pH 5.2, and in the buffer （pH 5.4） conserves most of its activity after incubated for 2 h at 37 ℃, but loses its activity sharply at 60℃. The α-L-arabinosidase has optimal activity of 1, 81 U/m at 55 ℃, pH 6.0, and in the buffer （ pH 6.0） retains more than 85% of activity after 2 h at 55 ℃. β-D-xylosidase activity is 0.04 U/mg.

关 键 词：链霉菌 16S RRNA基因 木聚糖降解酶系 

分 类 号：Q939.1[生物学—微生物学]