Abstract

Background: Biodiesel is considered as an upcoming alternative to overcome the fossil fuel dependence. Much research has been aimed at conversion of biobased platform molecules into fuels and multiple commodity products. In this regard, biodiesel is of topical interest which is obtained by transesterification reaction of renewable triglycerides in which glycerol is a valuable by-product. Conversion of this bioglycerol to value added products such as 2,3-butanediol (2,3-BD) which is a starting material for 1,3-butadiene, by microbial route is of great importance in promoting biodiesel industrialisation on a larger scale. Bioconversions have distinct advantages of sustainability as well as biodegradability with respect to biocatalysts, substrates, intermediates, and most of the times, products and by-products.

Methods: This review covers the literature on microorganisms mediated conversion of bioglycerol to 2,3 BD. This has been achieved by various strains of bacteria under aerobic, anaerobic conditions in batch as well as continuous modes of operation.

Results: There are few reports on microbial mediated conversion of bioglycerol (C3 diol) to 2,3-BD which is a C4 diol. Although a variety of strains have been reported for this conversion, but Klebsiella sp. gives highest (131.5 g/L) 2,3-BD yield by mutational studies leading to a reduction of by-products.

Conclusion: The review illustrates, the three stereoisomeric forms of (2,3-BD) produced by different bacterial strains along with pathway studies and their potent applications in various industries. Combination of strain improvement strategies will eventually lead in viable productivity of 2,3-BD production from biodiesel derived glycerol.

Keywords: Glycerol, 2, 3-butanediol, stereoisomers, bioconversion, metabolic pathway, genetic engineering.

Graphical Abstract