重组毕赤酵母产木聚糖酶条件的优化

对基因工程菌Pichia pastoris GS115-ATx在摇瓶发酵水平产木聚糖酶条件进行了优化.结果表明,该基因工程菌产木聚糖酶的最佳碳源为麸皮,最佳氮源为牛肉膏,有机氮源促进产酶的效果优于无机氮源.GS115-ATx产木聚糖的最佳甲醇诱导浓度为0.5%,在甲醇诱导的同时补加0.5%甘油能显著提高木聚糖酶的活性.研究发现,吐温20、吐温80、甜菜碱等表面活性剂均具有促进基因工程菌GS115-ATx产木聚糖酶的作用,其中甜菜碱的作用效果较佳.经SDS-PAGE电泳分析,GS115-ATx产生木聚糖酶的分子量约为19.0 kDa.发酵液上清中的木聚糖酶活性在甲醇诱导培养96 h后达到最大值.

Optimization of fermentation conditions for xylanase production by engineered Pichia pastoris

The optimal fermentation conditions for production of xylanase by engineered Pichia pastoris GS115-ATx in shake-flask cultivation was investigated.The results showed that the best carbon and nitrogen sources for xylanase production were bran and beef extract,respectively.Judging from their effect on xylanase production efficiency,organic nitrogen was better than inorganic nitrogen.The best methanol concentration was 0.5% for inducing xylanase expression.The xylanase activity was increased when 0.5% glycerin was added into the culture every 24 h.In addition,Toween 20,Toween 80,and betaine were found to increase the yield of xylanase,and among them betaine was the optimal stimulator.SDS-PAGE analysis revealed that the molecular weight of xylanase expressed by GS115-ATx was about 19.0 kDa.The xylanase activity of the culture supernatant reached its peak after 96-h methanol induction.