The Application Of Quorum Sensing In The Production Of Tyrosol And Salidroside In Escherichia.coli

The quorum sensing is a natural regulation method that is ubiquitous in nature bacteria.At present,the research on quorum sensing is mostly related to the number of bacteria and the relationship between colonies,and few successful cases have been applied to the study of metabolic regulation.In order to verify the application value of quorum sensing in the dynamic metabolic regulation of E.coli and further explore the application prospects of quorum sensing,this paper studies the effect of quorum sensing on the regulation of single bacteria and co-cultivation,as well as the optimal control of the co-cultivation system.By constructing a variety of control schemes based on quorum sensing,including self-limiting growth and carbon flux switch in the system of E.coli co-culture to produce salidroside,the main results obtained are as follows.(1)Regulation of single bacteria.The tyrosol-producing strain BMT21 using glucose,the tyrosol-producing strain BMT23 after changing the carbon source,and the BMT23 B with added BGL enzyme expression genes were constructed as growth-limited self-limiting tyrosol-producing strains based on quorum sensing.The quorum-sensing self-limiting growth strategy can limit the growth of strains and have little effect on tyrosol production.A carbon flux switch based on quorum sensing was added to the salidroside production strain BMS24,and it was found that it can increase the production of salidroside during the fermentation of single bacteria.(2)Co-cultivation regulation.Four single-regulation co-cultivation systems and three double-regulation co-cultivation systems were constructed using original strains and modified strains.The study found that when quorum sensing control self-limiting growth,carbon source regulation,BGL enzyme expression and carbon flux conversion switch co-exist,it can effectively increase the production of salidroside.Salidroside yield is the highest.After optimizing the fermentation conditions of the two co-cultivation systems BMT23T2B+BMS24S1 and BMT23T2B+BMS24S2 with the highest yields,the yields reached 1.13g/L and 1.18g/L,respectively,which was I more than 6 times the highest yield of salidroside in the original co-culture system.Studies have shown that quorum sensing has great application value in the production of specific metabolites.The regulation scheme constructed in this paper can also be directly applied to the production of other E.coli single bacteria or co-cultivation,and it also has highly efficient reference significance for other metabolites.