Biotransformation of biodiesel-derived crude glycerol using newly isolated bacteria from environmental consortia

Abstract

Abstract Oversupply of biodiesel-derived crude glycerol, a core by-product of biodiesel production process has become a great environmental and economical concern for growth of biodiesel industries. Biotransformation of this large volume of crude glycerol to value-added bio-products may directly benefit the environment and economic feasibility, encouraging the development of biodiesel plants. In our study, numerous bacterial strains isolated from environmental consortia were screened for their capability of converting crude glycerol to 2,3-BD which is a high worth green product used as a liquid fuel or fuel additive. An aerobic batch flask cultivation was carried out to access the kinetics of bio-product formation and glycerol utilization. The greatest producers of 2,3-butanediol (2,3-BD) identified by 16S rRNA gene sequences were Klebsiella pneumoniae, K. variicola and Serratia liquefaciens. The co-culture constructed by K. pneumoniae SRP2 and K. variicola SRP3 was capable of simultaneously converting crude glycerol to concurrently produce up to 27.87 g/L of 2,3-BD, yielding 0.73 g/g using 37.0 g/L glycerol under aerobic conditions in batch culture, showing great potential for biotransformation bioprocess.