Efficient production of bioethanol from waste glycerol using microwave irradiation induced mutant Escherichia coli

Abstract

Crude glycerol, an inevitable byproduct during biodiesel production, is emerging as a potential feedstock for fermentation, due to its availability and a reasonable price. The anaerobic digestion of glycerol derived from biodiesel manufacturing, in which COD was found to be 1010 g/kg, was studied in batch laboratory-scale reactors. Dissimilation of glycerol by Escherichia coli is strictly linked to their capacity to synthesize the highly reduced product 1,3-propanediol (1,3-PDO). The present study is focus on the development of adaptive mutant strains of Escherichia coli EC-MW (ATCC 11105), through microwave irradiation, at frequency 2.45 GHz and irradiation time 5 min pulse irradiation. The mutants were used for high bioethanol production from glycerol feedstock. Consequently, glycerol oxidative pathway (bioethanol) enhanced upon the parallel reduction in the 1,3-propanediol (1,3-PDO) pathway. The modified E. coli strains were able to increase bioethanol production upon fermentation reaching the level 280 g/L.