吸水链霉菌发酵生产谷氨酰胺转胺酶的补料研究

在吸水链霉菌(Streptomyces hygroscopicus)分批发酵研究的基础上，通过在菌体生长阶段指数流加葡萄糖，进行高细胞密度培养，获得了较高的菌体量；待菌体生长进入产酶期后，通过补加氮源，为产酶提供充足的氮源，其中通过流加蛋白质氮源，可以减少蛋白酶对成熟MTG的分解，促进产酶。结果表明，8~16 h采用较高的的比生长速率(0.15 h-1)，后期降低比生长速率(0.10 h-1)，此时得到的菌体量较高，可达到36 g/L，比分批发酵下的菌体量提高了80%。同时在培养基中添加50g/L的豆饼粉，最终酶活可达到5.79U/ml，提高了83%。

Improvement of MTG Production from Streptomyces hygroscopicus by Fed-batch Fermentation

In Streptomyces, MTG (Microbial Transglutaminase) is secreted and activated during the emergence of aerial hyphae rather than during the vegetative growth. The secretion and activation process were stopped when spores were formed. To obtain high cell density and high yield of MTG by Streptomyces hygroscopicus, the effects of exponential feeding of glucose and the addition of nitrogen source on MTG production were investigated. The results showed that keeping a high specific growth rate (0.15h-1) in 8~16h and a relative low specific growth rate (0.10h1) during later time could obtain highcell density, the DCW could reach 36 g/L which was increased by 80% compared to that in batch fermentation mode. The MTG activity reached 5.79U/ml by adding 50 g/L soybean meal in the initial medium, and was increased by 83%.