D-阿洛酮糖的生物转化及冷却结晶工艺优化

Optimization of bioconversion and cooling crystallization processes for D-allulose

D-阿洛酮糖作为一种具有多重生理功能的食品添加剂,是近年来的研究热点。为完善D-阿洛酮糖上下游生产工艺,选取3种不同微生物来源的D-阿洛酮糖3-差相异构酶(D-allulose 3-epimerase,DAEase)在大肠杆菌表达宿主BL21(DE3)中进行异源表达,通过对全细胞生物转化工艺的探索和不同重组菌催化能力的分析对比,发现重组表达了来源于多尔氏菌属(Dorea sp.CAG317)的DAEase的全细胞生物转化率达到32.60%。在此基础上对反应液进行色谱分离和纯化,得到高纯度的D-阿洛酮糖料液。对D-阿洛酮糖料液采取冷却结晶法析出晶体,结果显示采用优化后的冷却结晶工艺,D-阿洛酮糖结晶率达到了77.43%,纯度达到了98.70%。该研究为工业化生产D-阿洛酮糖提供重要参考。

D-allulose has been a hot research topic in recent years,which is a food additive with multiple physiological functions.To investigate the bioconversion of D-allulose,three different microbial sources of D-allulose 3-epimerases(DAEase)were selected for heterologous expression in E.coli BL21(DE3).Through the exploration of the whole-cell bioconversion and the analysis of the catalytic capacity of different recombinant strains,it was concluded that DAEase from Dorea sp.CAG317 was shown to have a more promising industrial potential with a conversion rate of 32.60%.Based on this,we carried out chromatographic separation of the reaction solution to obtain a high-purity D-allulose stock solution.We took the cooling crystallization method for D-allulose stock solution to precipitate crystals,and the results showed that the optimized cooling crystallization processes achieved a 77.43%crystallization rate and a 98.70%purity of the product.This study provides an important reference for the upstream and downstream processes for the industrial production of D-allulose.