| Institution: | (1) Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul, 151-921, South Korea;(2) School of Biotechnology and Bioengineering, Kangwon National University, Chuncheon, 200-701, South Korea;(3) Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, 200-701, South Korea;(4) Department of Food Science and Technology, Chungbuk National University, Cheongju, 361-763, South Korea; |
| Abstract: | Guanosine 5′-triphosphate (GTP) is the key substrate for biosynthesis of guanosine 5′-diphosphate (GDP)-l-fucose. In this study, improvement of GDP-l-fucose production was attempted by manipulating the biosynthetic pathway for guanosine nucleotides in recombinant Escherichia coli-producing GDP-l-fucose. The effects of overexpression of inosine 5′-monophosphate (IMP) dehydrogenase, guanosine 5′-monophosphate (GMP) synthetase
(GuaB and GuaA), GMP reductase (GuaC) and guanosine–inosine kinase (Gsk) on GDP-l-fucose production were investigated in a series of fed-batch fermentations. Among the enzymes tested, overexpression of Gsk
led to a significant improvement of GDP-l-fucose production. Maximum GDP-l-fucose concentration of 305.5 ± 5.3 mg l−1 was obtained in the pH-stat fed-batch fermentation of recombinant E. coli-overexpressing Gsk, which corresponds to a 58% enhancement in the GDP-l-fucose production compared with the control strain overexpressing GDP-l-fucose biosynthetic enzymes. Such an enhancement of GDP-l-fucose production could be due to the increase in the intracellular level of GMP. |
