Production Of Vanillin And Vanillic Acid By Microbial Conversion

More and more people pay attention to production of vanillin and vanillic acid because of its non-pollute,non-poisonous and with its by-products non-pollute.Many abroad companies strengthen the study of production of vanillin and vanillic acid by microbial conversion.Our country is on underway moment in this aspect,so we must strengthen the study of cooperation in order to stand in the vanillin and vanillic acid markets.This paper studied the production of vanillin and vanillic acid from isoeugenol or ferulic acid by enzymatic and microbial methods.Through repeated experiments, we found Novozyme435, Candida sp.99-125, Lipozyme TL IM and Lipozyme RM IM can not catalyze isoeugenol to vanillin,which show the reaction maybe not esterification.The method for producing vanillin from isoeugenol by enzymatic conversion with crude enzyme extracted from soybean was studied.The activity of LOX was lower.The substrate and product were analysis after reaction,but there is no change.Maybe there are some questions in the reaction system,so we had better look for new microbial enzyme.Three strains which were catenulate were screened for their ability to transform isoeugenol to vanillin from the microorganism,but the concentration of vanillin is very low.In the following experiments,vanillin was not detected in the fermentation culture of the three strains.It showed that maybe the strains were not steady,so that the ability of transformation was dropped.Synchronously,isoeugenol is poisonous to microorganism,and it is easily emulsification in the fermentation culture which could baffle the reaction,so we will choose ferulic acid as the substrate.StrainA1 was screened for its ability to transform ferulic acid to vanillic acid from the microorganism.Under the unoptimal conditions,the strain could transform 1g/L ferulic acid to 0.36g/L vanillic acid with a molar yield of 41.6% after 27h.After irradiation of ultraviolet to Streptomyces2036,vanillin had been detected only in trace amounts,about 2.1mg/L,but the strain could transform ferulic acid to vanillic acid in short time.Streptomyces2036 was screened for its ability to transform ferulic acid to vanillic acid.The optimal medium contained:glucose 5g/L,yeast extract 5g/L. Cultures in 250mL flasks containing 50mL medium which were brought to pH 5.0 were incubated shaking at 150r/min and 30℃.Under the optimum culture medium and fermentation conditions,Streptomyces2036 could produce vanillic acid when ferulic acid was added 16h after inoculation.The strain could transform 1g/L ferulic acid to 0.261g/L vanillic acid with a molar yield of 30.2% after 12h,and the enzyme catalyzing the transformation of ferulic acid into vanillic acid was mainly intracellular enzyme.