Isolation And Characterization Of Strains About Bioconversion Of Anethole Generate Anisic Acid And Optimization Of Fermentation Conditions

Anisic acid, a common flavoring, is a precursor substance used in the manufacture of a variety of spices and an important pharmaceutical intermediates, can be used for blood tests in medicine. There are two primary methods producing anisic acid in current industrial production by chemical oxidation and chemical synthesis, which exists disadvantages of high energy consumption and ease of pollution, however, the price of the man made anisic acid is far below the natural one. For that reason, the preparation of anisic acid with biological transformation is of great significance.In this study, bacteria strains which could grow on the medium with anethole as carbon source were isolated from the soil sample took from Guangxi star anise growing areas by enrichment and purification, then those strains resistanting high concentration of anethole and accumulating anisic acid were reisolated. After detecting the fermentation broth of strains by gas chromatography, a strain WGB31accumulating anisic acid reached to10.25%was obtained. The strain WGB31was identified as Burkholderia sp. through physiological and biochemical characterization of morphological identification, and16S rDNA molecular biological and phylogenetic analysis.After investigating various mono factor effecting on the production of anisic acid, three significant factors were chosed for Box-Behnken Design, and then analysed the experimental results by response surface regression analysis and significance test, the binomial equations and models on the production of anisic acid were obtained. The fermentation conditions of the stable point about this model are:glucose6g/L, peptone6g/L, pH6.2,culture medium volume61mL/250mL, inoculum concentration8%, substrate concentration4g/L, incubation temperature28℃, rotation speed180r/min and24h of conversion time. The validation experiments showed that the degradation rate of anethole is reach to78.75%, representing a1.5-fold increase from that of before optimization, and anisic acid generation rate of30.7%, increased by3times, the optimization effect is obvious.The results of this study provide a basis and reference for producing anisic acid by biotransformation method.