Ethylene glycol conversion to glycolic acid in Escherichia coli: Leveraging transcriptomic data for enhanced productivity

Ethylene glycol, a pivotal monomer from polyethylene terephthalate (PET) degradation, is crucial for transforming into high-value products to support a circular economy in plastics. However, the metabolic complexities and suboptimal fermentation results impede its efficient conversion to glycolic acid. In this study, the cell factory of Escherichia coli was successfully constructed for converting ethylene glycol into glycolic acid, advancing its application as a sustainable feedstock alternative in bioprocess. Based on transcriptomic data and metabolic engineering, 15 identified genes led to an obvious boost in production, up to 12.8 %. Adopting pH-controlled fermentation, strains YF2G*GA3 and YF2G*GA23 achieved unprecedented glycolic acid titers utilizing ethylene glycol in Escherichia coli. YF2G*GA3, in particular, attained a yield of 1.13 g/g with a yield of 91.87 %, greatly outperforming the original YFGA strain's 0.67 g/g yield. In conclusion, the power of metabolic engineering guided by transcriptomic data was exemplified. It not only provides new strategies for microbial platform of glycolic acid production, but also supports the circular plastic economy.