Trehalose is a disaccharide with many applications in cosmetics,refrigeration,and food.Trehalose synthase is a significant enzyme in trehalose production.Escherichia coli is usually used to express this enzyme heterol...Trehalose is a disaccharide with many applications in cosmetics,refrigeration,and food.Trehalose synthase is a significant enzyme in trehalose production.Escherichia coli is usually used to express this enzyme heterologously.Since E.coli is a pathogenic strain,we chose Corynebacterium glutamicum ATCC13032 as an engineering strain in this study for food safety reasons.Because of its poor permeability,we constructed two recombinant C.glutamicum strains using two anchor proteins,PorH,and short-length NCgl1337,to anchor trehalose synthase from Streptomyces coelicolor on the cell surface and synthesize trehalose directly from maltose.Studies on enzymatic properties indicated that NCgl1337S–ScTreSK246A had better enzyme activity and thermal stability than the free enzyme.After optimizing the whole-cell transformation,the optimal transformation condition was 35°C,pH 7.0,and OD600 of 30.Under this condition,the conversion rate of 300 g/L maltose reached 69.5%in a 5 L fermentor.The relative conversion rate was still above 75%after repeated five times.展开更多
基金the National Natural Science Foundation of China(No.32171471)Key Research and Development Project of Shandong Province,China(2019JZZY020605)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,Top-notch Academic Programs Project of Jiangsu Higher Education Institutions.
文摘Trehalose is a disaccharide with many applications in cosmetics,refrigeration,and food.Trehalose synthase is a significant enzyme in trehalose production.Escherichia coli is usually used to express this enzyme heterologously.Since E.coli is a pathogenic strain,we chose Corynebacterium glutamicum ATCC13032 as an engineering strain in this study for food safety reasons.Because of its poor permeability,we constructed two recombinant C.glutamicum strains using two anchor proteins,PorH,and short-length NCgl1337,to anchor trehalose synthase from Streptomyces coelicolor on the cell surface and synthesize trehalose directly from maltose.Studies on enzymatic properties indicated that NCgl1337S–ScTreSK246A had better enzyme activity and thermal stability than the free enzyme.After optimizing the whole-cell transformation,the optimal transformation condition was 35°C,pH 7.0,and OD600 of 30.Under this condition,the conversion rate of 300 g/L maltose reached 69.5%in a 5 L fermentor.The relative conversion rate was still above 75%after repeated five times.
