Screening and fermentation of high-yield glycolic acid strains

Abstract

Glycolic acid is an important chemical product widely used in various fields, including cosmetics, detergents, textiles, and more. Currently, microbial production of glycolic acid has disadvantages such as poor genetic stability, low yield, and high cost. Additionally, whole-cell catalytic production of glycolic acid typically requires the addition of relatively expensive sorbitol as a carbon source, which limits its industrial production. To develop an industrially applicable method for glycolic acid production, this study used ethylene glycol as a substrate to screen the glycolic acid-producing strains through whole-cell catalysis, obtaining a Rhodotorula sp. capable of producing glycolic acid. The strain was then subjected to UV mutagenesis and high throughput screening, and the positive mutant strain RMGly-20 was obtained. After optimization in shake flasks, the glycolic acid titer of RMGly-20 reached 17.8 g/L, a 10.1-fold increase compared to the original strain. Using glucose as the carbon source and employing a fed-batch culture in a 5 L fermenter, strain RMGly-20 produced 61.1 g/L of the glycolic acid. This achievement marks the preliminary breeding of a genetically stable glycolic acid-producing strain using a cheap carbon source, providing a new host for the biosynthesis of glycolic acid and promoting further progress toward industrial production.