Construction of genetically engineered bacteria producing L- rhamnose isomerase

Abstract

Rare sugars are sugars with very little content in nature, which have the characteristics of low calorie and little absorption. With the advancement of individuals' lives, people started to focus more and more on their physical well-being. At present, high-calorie sweeteners widely existing in the food and medicine fields have a trend of being replaced by low-calorie functional sweeteners. D-allose is an important rare sugar. Its physiological functions include anti-inflammation, neuroprotection, inhibition of cancer, adjuvant cancer treatment, immunosuppression, anti-oxidation, cryoprotection and so on. It has a good prospect in food, medicine, clinical and other fields. However, the amount of D-oxoxlose in nature is very small , and it is not easy to extract from natural products. However, the chemical synthesis method has many by-products and is not easy to purify. In this study, L-rhamnose isomerase (L-RhIase) from Bacillus subtilis was amplified, and the recombinant plasmid pET-22b-l-rhi was constructed. The recombinant plasmid was transformed into E.coli BL21star (DE3) to express L-RhIase. To provide theoretical and technical support for the efficient production of D-allose, L-RhIase was used to catalyze D piscose to D-allose.