Characterization and Xylanse Productivity of Streptomyces sp. WL-2

Xylanase 생산균 Streptomyces sp. WL-2의 특성과 효소 생산성

A strain WL-2 was isolated from soil as a producer of the extracellular xylanase, which catalyzes the hydrolysis of oat spelt xylan. The strain WL-2 was identified as Streptomyces sp. on the basis of its 16S rRNA sequence, morphology, cultural and physiological properties. The xylanase of culture filtrate was the most active at $60^{\circ}C$ and pH 6.0, and retained $90{\%}$ of its maximum activity at range of pH $4.5{\~}6.5$. In order to optimize the culture medium for xylanase production, ingredients of G.S.S medium were replaced by several carbohydrates. The carbohydrates such as ${\alpha}-cellulose$, oat spelt xylan and maltose increased dramatically the xylanase productivity of Streptomyces sp. WL-2. The maximum xylanase productivity was reached to 120 U/ml in the modified medium containing $1{\%}\;\alpha-cellulose$ and $1\%}$ maltose.

토양으로부터 세포외로 xylanase를 분비 생산하는 방선균 WL-2가 분리되었으며, 분리균의 16S rRNA 염기서열과 형태${\cdot}$배양${\cdot}$생리적 특성을 조사한 결과 Streptomyces속 균주로 확인되었다. 분리균의 배양상등액에 존재하는 xylanase는 pH 6.0과 $60^{\circ}C$의 반응조건에서 반응성이 가장 높았으며, pH $4.5{\~}6.5$ 범위에서 최대활성의 $90{\%}$ 이상을 나타냈다. Xylanase의 생산을 위한 배지를 최적화하기 위해서 G.S.S 배지성분을 여러 종류의 탄수화물로 대체하였다. ${\alpha}-Cellulose$, oat spelt xylan과 엿당과 같은 탄수화물은 Streptomyces sp. WL-2의 xylanase 생산성을 급격히 증가시키는 것으로 확인되었다. ${\alpha}-Cellulose(1\%)$와 엿당($1{\%}$)을 함유한 변형배지에서 xylanase의 최대생산성이 120 U/ml로 확인되었다.