Biosynthesis of Apigenin Glucosides in Engineered Corynebacterium glutamicum

• Published in: Journal of microbiology and biotechnology Vol. 34; no. 5; pp. 1154 - 1163
• Main Authors: Obed Jackson Amoah, Samir Bahadur Thapa, Su Yeong Ma, Hue Thi Nguyen, Morshed Md Zakaria, Jae Kyung Sohng
• Format: Journal Article
• Language: Korean
• Published: 한국미생물생명공학회 31.05.2024
• Subjects: apigenin; Corynebacterium; glucosylation; glycosyltransferase; glucosylation; apigenin; Corynebacterium; glycosyltransferase
• ISSN: 1017-7825; 1738-8872

Glucosylation is a well-known approach to improve the solubility, pharmacological, and biological properties of flavonoids, making flavonoid glucosides a target for large-scale biosynthesis. However, the low yield of products coupled with the requirement of expensive UDP-sugars limits the application of enzymatic systems for large-scale. C. glutamicum is a Gram-positive and generally regarded as safe (GRAS) bacteria frequently employed for the large-scale production of amino acids and biofuels. Due to the versatility of its cell factory system and its non-endotoxin producing properties, it has become an attractive system for the industrial-scale biosynthesis of alternate products. Here, we explored the cell factory of C. glutamicum for efficient glucosylation of flavonoids using apigenin as a model flavonoid, with the heterologous expression of a promiscuous glycosyltransferase, YdhE from Bacillus licheniformis and the endogenous overexpression of C. glutamicum genes galU1 encoding UDP-glucose pyrophosphorylase and pgm encoding phosphoglucomutase involved in the synthesis of UDP-glucose to create a C. glutamicum cell factory system capable of efficiently glucosylation apigenin with a high yield of glucosides production. Consequently, the production of various apigenin glucosides was controlled under different temperatures yielding almost 4.2 mM of APG1(apigenin-4β-O-β-glucoside) at 25℃, and 0.6 mM of APG2 (apigenin-7-O-β-glucoside), 1.7 mM of APG3 (apigenin-4β,7-O-β-diglucoside) and 2.1 mM of APG4 (apigenin- 4β,5-O-β-diglucoside) after 40 h of incubation with the supplementation of 5 mM of apigenin and 37℃. The cost-effective developed system could be used to modify a wide range of plant secondary metabolites with increased pharmacokinetic activities on a large scale without the use of expensive UDP-sugars.