Study On (R)-β-Hydroxyisobutyric Acid Synthetic Technique By Biocatalysis

Optical-pure(R)-β-hydroxyisobutyric acid(R-HIBA) is an important chiral building block in medicine,food and fine chemical products.It has attracted interest widely because of its important commercial interest.It is an important method to catalytic oxidate selectively methylacrylic acid to product R-HIBA by chemical synthesis.Howere,there are some shortage,such as low-yield,high costs,lot of by-products and serious pollution.In this study, production of R-HIBA from isobutyric acid was investigated using Candida rugosa.It studies more systematically the condition of Biological oxidation in term of optimize Bio-fermentation conditions and technology,and The gas chromatogram(GC) with FID(Fire iron deteteetor) was applied to detect and analyze their appearance.In this study,R-HIBA is synthesized through the method of Yeast whole-cell catalytic convertion,so biomass has a considerable effect on bio-catalytic oxidation.The Candida rugosa was improved by UV-induction and isolating and screening method.High-yield mutant was obtained,which increases the biomass by 14.3%,with the yield of product of the R-HIBA increased by 18%compared with the parent strain.After optimizing the conditions and system of reaction,a conclusion was drawn:It was advantageous to cell growth and coversion of R-HIBA production,when the concentration of substrate(IBA),Glu density was 20g/L and 30g/L,respectively,pH was 7.3,the volume of liquild was maintained 20%(v/v).Through the fed-batch fermentation,the reaction system was controlled according to the optimization conditions.when the culture time reached 112h,the concentration of production of R-HIBA was up to 60.9g/L,with the average productivity 0.356 g/L and the molar conversion yield of 41.2%.Since substrate and product are organic acids and both of them have a higher polarity, easy adsorption,high boiling point,hardness to vaporize et.the samples were first derived for the esters,which is beneficial to treat and test.The sample of substrate and product were analyzed qualitatively comparing with gas cheromatographic chart of standard,and the internal standard method was used to determine their quantity of sample,with chloroform as internal standard sample.Specific rotation and IR was measured for the product.