Optimization Of Fermentation Condition Of Aspergillus Oryzae Producing Aminoacylase

Aminoacylase with specific optical isomer can selectively hydrolyze N-acyl-DL-amino acids, optically pure L-or D-amino acids can be obtained through separation.The specific feature can be utilized to produce large-scale production of amino acid in industrial.Therefore, aminoacylase production strains selection and optimization of fermentation conditions with high energy and high stereoselectivity is highly efficient, low-cost basis for preparation of amino acids. Now aminoacylase that split amino acids is mostly producted by Aspergillus oryzae fermentation,but the yield and quality can not meet the needs of industrial production.To solve this problem, the ion mutation strains of Aspergillus oryzae was used as the experimental object in this thesis,which were ferment by changing carbon source,nitrogen source,phosphate,liquid volume,temperature,rotate speed and other factors to find the optimal fermentation conditions. Seek to further improve Aspergillus oryzae aminoacylase enzyme activity from the external environment, as industrialization and mass production basis.By single factor test, the effect of medium components and culture conditions on the yield of aminoacylase were studied. The optimal carbon source was wheat bran;the optimal complex nitrogen sources were peptone and urea;the optimal phosphate was NaH2PO4. The results showed that liquid fermentation aminoacylase was not inducible enzyme,add zymolyte no influence on aminoacylase activity. The addition of surfactant could not improve the enzyme activity of aminoacylase. On the basis of the single-factor test,nine factors and three levels were tested by the orthogonal design. the optimized medium was determined through test results and analysis of variance:wheat bran 1%, peptone 1.25%,urea 0.75%, MgSO4 0.15%,NaH2PO4 0.2% ,not to mix zymolyte and surface active agent. The optimal culture conditions were attained,which consisted of such factors as 20ml culture medium into 250ml triangular flask, rotation speed 150 r/min,pH 6.5, inoculum concentration 8% ,ferment temperature 40℃,time 50h. Under these condition 3 batches of samples were fermented, the average aminoacylase activity up 850μmol/g?h. Compared with the former 75μmol/g?h,activity increased 11 times.In addition,the experiment about the purification and structure determination of the aminoacylase were done.Because limited test conditions, the effect of aminoacylase purification was not ideal.We need to continue to study aminoacylase purification.