Efficient utilization of cellulosic materials as renewable resources is drawing increasing degree of attention in the scientific community. As part of our endeavor to improve the production of cellulase complex system, several factors that influence production of cellulolytic enzyme system have been studied. Those factors studied are: cellulose source, medium composition, aeration and surfactant etc.. The effects of temperature, pH and metal ions on cellulase activity and stability were also studied.
For the production of cellulolytic enzymes using $\underline{T}$. $\underline{viride}$ QM 9414, optimal concentration of $KH_2PO_4$ was 0.01M. Casitone was a good protein source compared with others studied, such as peptone, yeast extract, tryptone and casein. Optimum concentration of glucose and Tween 80 was 0.3% for cellulase production. Using rice straw as carbon source, the final pH was about 7, and cellulose medium supplemented with rice straw resulted in high productivity of cellulolytic enzymes particularly in cellobiase and moderate pH changes during fermentation process, 3.5 to 7. Optimal oxygen transfer rate was found to be about 50 mM $O_{2/\ell}$-hour for enzyme production.
Optimum pH and temperature of cellulolytic enzyme was 5.2 and 60℃, respectively. The highest stability of CMC activity and FP activity was obtained about 5.2 and 4.6 of pH value respectively at 50℃. At 50℃ FP activity was more stable than CMC activity. Copper ion inhibited enzyme activity markedly at 0.1% concentration.
Cellulolytic enzyme 의 productivity 를 높이기 위하여 cellulose source 와 medium composition 그리고 aeration 정도와 surfactant 농도를 fermentation variables 로 하여 최적화 하는 실험을 하였다. 또한 enzyme 의 activity 와 stability 에 관한 온도와 pH 그리고 금속이온의 영향을 살펴보았다.
$\underline{T}$. $\underline{viride}$ QM 9414 균주를 사용하였을 때 $KH_2PO_4$ 와 glucose와 Tween 80 은 각각 0.01 M, 0.3%, 0.3% 의 concentration 에서 cellulolytic enzyme 의 productivity 가 높았으며, protein source로는 casitone 이 좋은 결과를 나타냈다. 볏짚을 탄소원으로 하였을 때 culture broth final pH 는 7 부근이었으며 볏짚과 Avicel 을 반반씩 섞어 탄소원으로 하였을 때 cellulolytic enzyme의 productivity 가 높게 특히 cellobiase 의 productivity 가 눈에 띄게 증가하였으며, 이 경우 fermentation 에 동안에 pH 가 3.5 이하로 떨어지지 않고 final pH 는 6부근으로 나타났다.
최적 O.T.R.은 50 mM $O_2/ℓ-hr$로 나타났다.
Cellulolytic enzyme 의 optimum pH 와 optimum temperature는 각각 5.2 와 60℃ 였고 enzyme stability는 50℃ 에서 CMC activity 와 FP activity 가 각각 pH 5.2 와 pH 4.6 에서 가장 높은 것으로 나타났다.
