Glycolic acid production using ethylene glycol-oxidizing microorganisms

Screening for microorganisms oxidizing ethylene glycol to glycolic acid was carried out. Among stock cultures, several yeasts and acetic acid bacteria showed high glycolic acid producing activity. Pichia naganishii AKU 4267 f ormed the highest concentration of glycolic acid, 35.3 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 26.0%). Among soil isolates, Rhodo torula sp. 3Pr-126, isolated using propylene glycol as a sole carbon source , formed the highest concentration of glycolic acid, 25.1 g/l, from 10% (v/ v) ethylene glycol (molar conversion yield, 18.5%). Rhodotorula sp. 3Pr-126 showed higher activity toward 20% (v/v) ethylene glycol than P. naganishii AKU 4267. Optimization of the conditions for glycolic acid production was investigate d using P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126. Under the optim ized conditions, P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126 formed 105 and 110 g/l of glycolic acid (corrected molar conversion yields, 88.0 a nd 92.2%) during 120 h of reaction, respectively.