1,3-Propanediol production using crude glycerol from biodiesel conversion

As an important immediate non-fuel chemical, 1,3-Propanediol (1,3-PDO), has been received high attention in recent researches because of the wide application in polymer industry. In this study, 1,3-PDO from glycerol using Klebsiella pneumoniae ATCC 8724 was investigated in batch fermentation. To obtain high yield of 1,3-PDO, the main factors of this fermentation were optimized. Comparing with aerobic condition, the anaerobic culture was more suitable for 1,3-PDO production by K. pneumoniae. The optimum culture pH was 7.5. 1,3-PDO production was evaluated with substrate concentration from 30 g/l to 60 g/l. The maximum production yield was achieved 0.74 mol/mol when initial concentration of glycerol was 40 g/l. Crude glycerol as a famous by-product of biodiesel conversion was employed as an alternative feedstock instead of pure glycerol for 1,3-PDO conversion. Based on the optimum conditions of pure glycerol fermentation, the inhibitory effect of salts, that are the main impurities of crude glycerol, was evaluated in this study. The performance of 1,3-PDO production using crude glycerol was compared with that of pure glycerol. The cells grew better with crude glycerol fermentation and the highest yield of 1,3-PDO (0.65 mol/mol) was achieved from crude glycerol. This result indicated that crude glycerol from biodiesel conversion was feasible to apply in conversion of valuable chemical 1,3-PDO using batch fermentation in large scale.