产蛋白酶菌Planomicrobium sp.L-2发酵条件的优化

Optimization of Fermentation Conditions of A Protease-Producing Strain Planomicrobium sp.L-2

通过优化从长蛸胃肠道筛选得到的产蛋白酶菌Planomicrobiumsp.L-2菌株的发酵条件,提高其产蛋白酶的活力。采用单因素实验研究发酵培养基的最佳碳源、氮源以及最佳发酵条件,采用Box-Behnken设计方法进行响应面实验设计,进一步优化培养基组成。结果表明,最佳培养基组成及发酵条件为:可溶性淀粉0.73%、蛋白胨0.68%、酵母膏0.15%、磷酸高铁0.01%、海水,培养基初始pH值8.0,接种量8%,发酵温度25℃,发酵时间3.5d。优化后,所产蛋白酶的最高酶活力为1 457U·mL-1,比优化前提高约2倍。

A protease-producing strain Planomicrobiumsp.L-2was isolated and identified from gastrointestinal tract of Octopus variabilis.To increase the yield of proteases in Planomicrobiumsp.L-2,the optimal fermentation conditions for producing protease,including carbon source,nitrogen source,fermentation time,fermentation temperature,initial pH value of medium,and inoculum amount were studied by single factor experiments.On the base of that,response surface analysis was applied to optimize the compositions of fermentation medium of Planomicrobiumsp.L-2for producing protease.The optimal medium was composed of soluble starch 0.73%,peptone 0.68%,yeast extract 0.15%,FePO40.01%in sea water with the initial pH value of 8.0.And then the medium with 8%inoculum amount was cultured at 25℃for 3.5d.Under these optimal conditions,the activity of proteases produced by Planomicrobiumsp.L-2 was high up to 1 457U·mL^-1,which was approximately 2times higher than that of the original condition.