The Molecular Mechanism Preliminary Study Of Lactobacillus Plantarum Biosynthesis Phenyllactic Acid

Phenyllactic acid(PLA)is a new type of biological preservatives founded in recent years,which can effectively inhibit gram-negative,positive for the growth of bacteria and fungi.This experiment as lactobacillus plantarum YM-4-3 to the research object,firstly using high performance liquid chromatography(HPLC)method to determining the concentration of glucose in the MRS medium that influencing phenyllactic acid production.It is found that increasing concentration of glucose in the culture medium(0 g/L,30 g/L,60 g/L),phenyllactic acid yield increase first and then decreased,30 g/L glucose can produce a maximum level of phenyllactic acid 104.82 mg/L;To explore with glucose as raw material to the molecular mechanism of lactobacillus plantarum synthesis phenyllactic acid,we used the KEGG database to determine the synthesis of phenyllactic acid metabolic pathways.Its biosynthesis core way is that phenylalanine is used as the substrate while α-ketone amino as the receptor,then by ammonia reaction,the product,phenypyruvate(PPA),would generate PLA by dehydrogenase.The main metabolic productions of PLA are dihydrodiol,1-bromo-2,3-phenylpropanes etc.Based on these approaches and the corresponding database,we screened 10 genes,using quantitative PCR method for determining the differences in gene expression.Then,this study selected prehenate dehydrogenase as the research object,on the carrer of plasmid PZ8048,Lactococcus lactis NZ9000 protein heterologous expression for host and nisin induction,the result is in nisin concentration of 20 ng/mL,the protein induced effect is best.Finally,the experiment to the induced strain before and after induction strains and plasmid pNZ8048 strains as the research object of fungi and bacteria such as bacteriostatic experiment,get the gene for a negative control results.This experiment will help to clarify the biosynthetic pathways of PLA molecular regulation mechanism of the role,guidance for the systematic design of PLA provides the theory basis for industrialized production.