High-Yield Synthesis of 2′-Fucosyllactose from Glycerol and Glucose in Engineered <i>Escherichia coli</i>
Luyao Wang, Kang Zhang, Shengqi Gao, Mengwei Zhang, Tongle Liu, Bohan Cai, Lei Wang, Lingqia Su, Jing Wu, Sheng Chen
Abstract
2′-Fucosyllactose (2′-FL) is vital for the growth and development of newborns. In this study, we developed a synthesis pathway for 2′-FL in Escherichia coli BL21 (DE3). Then, we optimized the solubility of α-1,2-fucosyltransferase, thereby enhancing the production yield of 2′-FL. Based on this finding, we further enhanced the expression of guanosine inosine kinase Gsk and knocked out the isocitrate lyase regulator gene iclR . This strategy reduced the formation of byproduct acetate during the metabolic process and alleviated carbon source overflow effects in the strain, resulting in further improvement of the yield of 2′-FL. In a 3 L bioreactor, employing fed-batch fermentation with glycerol and glucose as substrates, the engineered strain BWLAI-RSZL exhibited impressive 2′-FL titers of 121.9 and 111.56 g/L, along with productivity levels of 1.57 and 1.31 g/L/h, respectively. The reported 2′-FL titers reached a groundbreaking level, irrespective of the carbon source employed (glycerol or glucose), highlighting the significant potential for large-scale industrial synthesis of 2′-FL.