表面活性剂对纳豆芽胞杆菌产维生素K2(MK-7)的影响

Effect of surfactant on vitamin K2(MK-7)production by Bacillus natto

纳豆芽胞杆菌因具有发酵生产维生素K2的能力而备受关注,但由于维生素K2分子量较大,很难通过自由扩散分泌至胞外。为了促进维生素K2的胞外分泌,进一步提高产量,本研究以前期诱变选育获得的一株纳豆芽胞杆菌ND-1-A27为研究对象,考察不同种类表面活性剂对维生素K2浓度、菌体生长、细胞形态及细胞膜流动性的影响。结果表明:非离子型表面活性剂Triton X-100、聚氧化乙烯(POE)和Tween 40在一定添加用量范围内对菌株ND-1-A27发酵生产维生素K2均具有促进作用,其中添加1 g/L的Triton X-100促进效果最佳。在此条件下,菌株发酵生产MK-7产量提高到37.96 mg/L,比对照提高了143.18%。

Bacillus natto is a good vitamin K2 producer.However,due to the high molecular weight of vitamin K2,it is difficult to be secreted out of the cell through free diffusion.In order to promote the exocytosis of vitamin K2 and increase the vitamin K2 production,a strain of Bacillus natto ND-1-A27 obtained by laboratory mutagenesis was used as the research object,and the effects of different surfactants on vitamin K2 production,cell morphology of the cell membrane fluidity and the bacteria growth were studied.The nonionic surfactant Triton X-100,poly(ethylene oxide)(POE)and Tween 40 could promote the production of vitamin K2 by strain ND-1-A27 in a certain range.Furthermore,the addition of 1 g/L Triton X-100 could enhance the production of vitamin K2.With addition of 0.1%Triton X-100,the yield of MK-7 was increased to 37.96 mg/L,143.18%higher than that of the control.