Effect of Xylan on Production of Xylanolytic Activity from Penicillium verruculosum

Penicillium verruculosum의 Xylan분해활성도의 생성에 대한 Xylan의 영향

During the cultivation of Penicillium verruculosum in the medium containing xylan as a sole carbon source for 26 days, xylanolytic activity and some changes were investigated. Protein content and xylanolytic activity, p-Nitrophenyl-$\beta$-D-xylopyranoside (PNPX), p-Nitrophenyl-$\beta$ -D-glucopyranoside (PNPG) hydrolytic activities were increased until 8 days but reducing sugar content was not correlated to protein content. When crude proteins from the culture broth were separated on SDS-PAGE, distribution of proteins was different from the culture broth of cellobiose octaacetate (COA) medium. The culture broth of xylan medium had high hydrolytic activity on xylan but not on cellulose. Furthermore, xylanolytic products were showed xylose, xylobiose and oligosaccharides on thin layer chromatography, and xylobiose was major product. Those result suggested that xylanolytic activity of culture broth was endo-type hydrolysis. Optimum temperatures of xylanolytic activity and PNPX hydrolytic activity of culture broth were 50~6$0^{\circ}C$ and 60~7$0^{\circ}C$, respectively and optimum pHs were 3.0~4.0 and 4.0~5.0, respectively.

Penicillium verruculosum을 xylan을 함유한 액체배지에서 26일간 배양하면서 xylan 분해활성도를 비롯한 몇 가지 변화를 관찰하였다. Xylan과 PNPX 분해활성도는 단백질량의 증가와 함께 배양 8일까지 급격히 증가하였으나 배양액 중의 환원당의 변화와는 비례하지 않았다. 배양 12일째의 배양상징 액을 탄소원으로서 cell-obiose octaacetate를 가한 배양상징액과 함께 전기영동하였을때 서로 다른 단백질 분포양상을 보였으며 본 배양상징액에 있어 섬유소 성분들에 대한 분해활성도는 거의 나타나지 않은 반면 xylan에 대해서는 매우 높은 활성도를 나타냈다. 배양 상징 액에 xylan을 가했을 때 반응 생성물로서 xylose와 xylobiose를 비롯하여 소당류들이 생성됨으로서 endo-type의 분해활성도로 추정 되었으며 이 때 xylobiose가 가장 많은 비율을 차지했다. Xylan과 PNPX분해 활성도에 대한 배양 상징액의 최적온도는 각각 50~6$0^{\circ}C$와 60~7$0^{\circ}C$였으며 최적pH는 각각 3.0-4.0과 4.0-5.0이었다.