重组蔗糖异构酶在短短芽孢杆菌中的表达及发酵优化

Expression and Fermentation Optimization of Recombinant Sucrose Isomerase inBrevibacillus choshinensis

DOI：10.3969/j.issn.1673-1689.2019.01.004

中文关键词: 蔗糖异构酶 短短芽孢杆菌 启动子 发酵优化

英文关键词: sucrose isomerase,Brevibacillus choshinensis,promoter ,fermentation optimization

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中文摘要:

对重组菌株Brevibacillus choshinensis/pNCMO2-SI摇瓶发酵产蔗糖异构酶进行研究，进一步探讨了3 L发酵罐不同发酵条件对菌体生长及产酶的影响。结果表明，摇瓶发酵后胞外酶活为50 U/mL，最优3 L发酵罐培养条件为：初始碳源为葡萄糖质量浓度10 g/L，初始氮源为多聚蛋白胨、牛肉浸膏质量浓度各15 g/L，发酵温度30 ℃，溶氧30%，在此条件下得到的最高酶活为275 U/mL。为了探索启动子对蔗糖异构酶表达的影响，分别选取来源于枯草芽孢杆菌的启动子Papr-E，Pnpr-E，Pamy以及来源于巨大芽孢杆菌的启动子Pxyl进行研究。结果表明，使用启动子Papr-E的表达量最高。进一步优化摇瓶发酵条件，重组菌株BCpNapr-SI摇瓶发酵的胞外上清酶活为137 U/mL，在此条件下进行3 L发酵罐发酵，最终发酵上清胞外酶活为485.5 U/mL，是未优化启动子的1.76倍。

英文摘要:

The fermentation of sucrose isomerase produced by recombinant strainBrevibacillus choshinensis/pNCMO2-SI was studied. The effects of different fermentation conditions on the growth and enzyme production of 3 L fermenter were further investigated. The results showed that the extracellular enzyme activity was 50 U/mL through shake-flask cultivation. The optimal 3 L fermenter culture conditions were as below：10 g/L glucose for initial carbon source，15 g/L polypeptone and 15 g/L beef extract for initial nitrogen source，30 ℃ cultivation and 30% for dissolved oxygen，the highest enzyme activity obtained under this condition was 275 U/mL. In order to study the effect of the promoter on the expression of sucrose isomerase，the promoters Papr-E，Pnpr-E，Pamy derived fromBacillus subtilisand the promoter Pxyl derived from Bacillus megaterium were selected for research，respectively. The results showed that the highest activity of sucrose isomerase was obtained by the promoter Papr-E. The fermentation conditions of the shake flask were further optimized. The extracellular supernatant activity of the recombinant strain BCpNapr-SI was 137 U/mL. Under this condition，in the 3 L fermenter，the extracellular enzyme activity of the final fermentation supernatant was 485.5 U/mL，which was 1.76 folds of that of the original promoter.

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