Gene Extraction,Expression Identification And Preliminary Evaluation Of Application Potential Of Acetaldehyde Dehydrogenase From Lactobacillus Plantarum

Acetaldehyde dehydrogenase(ALDH)is a common oxidoreductase,one of acetaldehyde dehydrogenases,which converts toxic acetaldehyde into harmless acetyl-co A.At present,there are more and more social activities using wine as media,and alcohol(ethanol)is catalyzed into acetaldehyde when it enters human body.Acetaldehyde accumulation in human body will affect the body and even endanger life and health.Adding exogenous ALDH can reduce the risk of damage to the collective.The main component of commercial antidotics is ALDH,but there are some deficiencies such as high cost and complex extraction steps.Extracting ALDH by probiotic fermentation can improve these deficiencies.Lactobacillus plantarum is a probiotic recognized as safe in the world.This study takes Lactobacillus plantarum strains as the starting point,using gene mining technology,and using Lactobacillus plantarum and acetaldehyde dehydrogenase as key words.Search the NCBI(National Center for Biotechnology Information)for a potential acetaldehyde dehydrogenase.In addition,a hypothetical acetaldehyde dehydrogenase was obtained,which was effectively expressed in the host cells of Escherichia coli,and acetaldehyde dehydrogenase with high catalytic activity or better thermal stability was obtained.On this basis,the induction conditions were optimized and the stability and alcohol tolerance of the enzyme in the simulated gastrointestinal environment were tested.The overall research results were as follows:1.Using gene mining technology,L.plantarum and acetaldehyde dehydrogenase were used as key words to search for a potential Lactobacillus plantarum acetaldehyde dehydrogenase in NCBI database.A hypothetical Lactobacillus plantarum acetaldehyde dehydrogenase(Lp ALDH)was extracted from the genome of Lactobacillus plantarum.The activity of Lactobacillus phytoacetaldehyde dehydrogenase in fermentation broth was detected to be 195U/m L.After purification by affinity chromatography,the specific activity reached 1709 U/mg.The optimum temperature is 35℃ and the optimum p H is 8.0.The temperature stability,p H stability and metal ion characteristics of Lp ALDH were studied,and the induction conditions were optimized.2.The function of acetaldehyde dehydrogenase to metabolize alcohol is utilized.In the early stage of being used as a functional food additive,the simulated gastrointestinal environment and alcohol tolerance test of acetaldehyde dehydrogenase are carried out.An artificial gastric juice and an artificial intestinal juice are simulated to test the stability of the enzymes,and alcohol of different concentrations is added to test the enzyme’s tolerance.The results showed that the recombinant enzyme had high stability in low concentration alcohol,and the residual enzyme activity remained over 75% within 70 min.It has high stability in the simulated gastrointestinal environment and can digest itself without being affected by the gastrointestinal environment.This study lays a solid foundation for further molecular modification of acetaldehyde dehydrogenase,optimal host selection for expression and development and application of health care products.