地衣芽孢杆菌ZJUEL31410产胞外弹性蛋白酶的分批发酵研究

Research on Batch Fermentation of Extracellular Elastase by Bacillus Licheniformis ZJUEL31410

为了获得高产弹性蛋白酶的地衣芽孢杆菌ZJUEL31410的分批发酵条件,采用5L生物发酵罐对地衣芽孢杆菌ZJUEL31410胞外弹性蛋白酶的分批发酵过程和发酵条件进行研究。结果发现,弹性蛋白酶的合成与菌体生长部分相关,细胞生长在24h时达到最大(菌体干重为8.9g/L);发酵6h时比生长速率(μ)达到最大值0.18,弹性蛋白酶合成在30h达到最大值373U/mL;在搅拌速度500r/min,初始葡萄糖质量分数为7.4%条件下,弹性蛋白酶活最高,体系中溶氧最多;提高搅拌功率可改善菌体的代谢过程,加快代谢速率,提高弹性蛋白酶活性。本文为地衣芽孢杆菌规模分批发酵和流加发酵产弹性蛋白酶提供试验依据。

The objective of the current study was to screen and construct the optimal batch cultivation conditions for elastase production by Bacillus licheniformis ZJUEL31410. The course of batch cultivation and batch cultivation conditions for elastase production were investigated with 5 L bioreactor. The experimental results demonstrated that elastase production did not overly associate with cell growth. Cell growth was reaching to the maximum （DCW： 8.9 g/L） at 24 h of culture time. The growth rate（μ） at 6 h was reaching to the maximum point （0.18）, however the maximum elastase activity was 373 U/mL at 30 h. Under conditions of 500 r/min stirring rate, 7.4% initial glucose concentration, elastase production and the dissolved oxygen of the cultivation medium have both reached the highest value. The increasing of shaking power can improve cell growth of Bacillus licheniforrnis ZJUEL31410 and elastase activity in some extent. Current research results provide the experimental bases for large-scale batch and fed-batch cultivation of elastase.