Immobilization of (S)-mandelate dehydrogenase and its catalytic performance on stereoselective transformation of mandelic acid

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• 作者：Peng Wang^a ; Dali Li^a ; ^{biolidali@gmail.com" class="auth_mail} ; Junfang Yang^a ; Lei Jiang^a ; Jing Feng^a ; Chengli Yang^a ; ^b ; Ruofu Shi^a
• 关键词：Biotransformation ; Immobilization ; (S)-Mandelate dehydrogenase ; Chitosan
• 刊名：Journal of the Taiwan Institute of Chemical Engineers
• 出版年：May, 2014
• 年：2014
• 卷：45
• 期：3
• 页码：744-748
• 全文大小：698 K

文摘

(S)-Mandelate dehydrogenase (SMDH) is a FMN-dependent enzyme and catalyzes the oxidation of (S)-mandelic acid to benzoylformic acid, resulting in the reduction of FMN. SMDH was immobilized on chitosan beads through glutaraldehyde by Schiff base linkage, and its immobilization yield was 78% and activity was 12.8 U/g. Some characteristics of immobilized SMDH were evaluated. It was found that its optimal pH was 3.4 and optimal temperature was 45 掳C. The K_m value of immobilized SMDH for racemic mandelic acid was 0.27 mM and that for ferricyanide was 0.75 mM. Compared with immobilized SMDH, the K_m values of soluble SMDH for racemic mandelic acid (0.92 mM) and ferricyanide (3.8 mM) were higher. The V_max was 0.49 渭mol/min. The immobilized SMDH showed some improvement on thermal stability and storage stability, with a 5-fold reduction of the deactivation rate for 45 掳C heat treatment and that for 4 掳C storage was about 1.4-fold. The stereoselective biotransformation of mandelic acid was studied using immobilized SMDH, with the cofactor FMN regenerated by low-cost ferricyanide. The ee value of (R)-mandelic acid in the final reaction mixture was above 99%.