Enzyme engineering for optimizing biosynthesis of 2,4-dihydroxybutyric acid via the synthetic threose-dependent glycolaldehyde assimilation (STEGA) pathway

) on D-threose compared to the wild-type enzyme. As a consequence of these improvements, co-expression of both engineered enzymes in the STEGA pathway significantly enhanced EG-to-DHB bioconversion, achieving a 68% increase in final DHB titer (5.2 ± 0.11 mM) and a 23% improvement in carbon yield (0.16 ± 0.003 Cmol/Cmol).