Modification of emodin and aloe-emodin by glycosylation in engineered Escherihia coli

作者：Ghimire Gopal Prasad; Koirala Niranjan; Pandey Ramesh Prasad; Jung Hye Jin; Sohng Jae Kyung^*

来源：World Journal of Microbiology and Biotechnology, 2015, 31(4): 611-619.

DOI：10.1007/s11274-015-1815-4

• Glycosylation
• Anthraquinone
• Emodin
• Aloe-emodin
• Biotransformation

Glycosyltransferase from Bacillus licheniformis DSM13 (YjiC) was used for enzymatic modification of emodin and aloe-emodin in vitro and in vivo. In order to increase the availability of UDP-glucose, three genes involved in the production of precursors of NDP-sugar in Escherichia coli BL21 (DE3) viz. d-glucose phosphate isomerase (pgi), d-glucose-6-phosphate dehydrogenase (zwf), and UDP-sugar hydrolase (ushA) were deleted and glucose-1-phosphate urididyltransferase (galU) gene was over expressed. To improve the yield of the products; substrate, time and media parameters were optimized, and the production was scaled up using a 3 L fermentor. The maximum yield of glycosylated products of emodin (emodin-O-beta-d-glucoside) and aloe-emodin (aloe-emodin-O-beta-d-glucoside) were approximately 144 A mu M (38 mg/L) and 168 A mu M (45 mg/L) respectively, representing almost 72 % and 84 % bioconversion of emodin and aloe-emodin when 200 A mu M of emodin and aloe-emodin were supplemented in the culture. Additionally, the emodin and aloe emodin major glycosylated products exhibited the highest stability at pH 8.0 and the stability of products was up to 70 A degrees C and 60 A degrees C respectively. Furthermore, the biological activities of emodin and its major glucoside (P1) were compared and their anti-cancer activities were assayed in several cancer cell lines. The results demonstrate that YjiC has the capacity to catalyze the glycosylation of these aromatic compounds and that glycosylation of anthraquinones enhances their aqueous solubility while retaining their biological activities.

• 出版日期2015-4