Immobilisation and characterisation of biocatalytic co-factor recycling enzymes, glucose dehydrogenase and NADH oxidase, on aldehyde functional ReSyn鈩?polymer microspheres

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• 作者：Busisiwe V. Twala^a ; B. Trevor Sewell^b ; Justin Jordaan^a ; ^{jjordaan@csir.co.za}
• 关键词：Immobilisation ; Dehydrogenase ; Oxidase ; ReSyn&trade ; Stability ; Biocatalysis
• 刊名：Enzyme and Microbial Technology
• 出版年：2012
• 期刊代码：26_01410229
• 类别：ce
• 出版时间：10 May, 2012
• 卷：50
• 期：6-7
• 页码：331-336
• 文件大小：308 K

摘要

The use of enzymes in industrial applications is limited by their instability, cost and difficulty in their recovery and re-use. Immobilisation is a technique which has been shown to alleviate these limitations in biocatalysis. Here we describe the immobilisation of two biocatalytically relevant co-factor recycling enzymes, glucose dehydrogenase (GDH) and NADH oxidase (NOD) on aldehyde functional ReSyn鈩?polymer microspheres with varying functional group densities. The successful immobilisation of the enzymes on this new high capacity microsphere technology resulted in the maintenance of activity of 鈭?0%for GDH and a maximum of 15.4%for NOD. The microsphere variant with highest functional group density of 鈭?500 渭mol g^鈭? displayed the highest specific activity for the immobilisation of both enzymes at 33.22 U mg^鈭? and 6.75 U mg^鈭? for GDH and NOD with respective loading capacities of 51%(0.51 mg mg^鈭?) and 129%(1.29 mg mg^鈭?). The immobilised GDH further displayed improved activity in the acidic pH range. Both enzymes displayed improved pH and thermal stability with the most pronounced thermal stability for GDH displayed on ReSyn鈩?A during temperature incubation at 65 掳C with a 13.59 fold increase, and NOD with a 2.25-fold improvement at 45 掳C on the same microsphere variant. An important finding is the suitability of the microspheres for stabilisation of the multimeric protein GDH.