BACKGROUND Production of biobased chemicals from renewable resources is a green starring approach that serves as a substitute to petroleum derivatives. Bioglycerol, with its growing production as a co-product of biodiesel, is an attractive low-cost feedstock for the synthesis of platform chemicals by microbial fermentation. 2,3-butanediol (2,3-BDO) is amongst the top biorefinery platform chemicals that can be produced by glycerol fermentation. RESULTS The `Circular Economy' concept is demonstrated by converting the by-product bioglycerol using a cell-free extract of Enterobacter aerogenes NCIM 2695 (National Collection of Industrial Microorganisms, NCIM), yielding 22 g L-1 2,3-BDO, in 96 h, 98% atom economy and 0.4 g/g E factor. The cell-free bioglycerol conversion to 2,3-BDO was proved using a modified procedure for determining glycerol dehydrogenase enzyme assay by protein analysis and it was also shown to be cell-bounded. CONCLUSION Our study offers an effective utilization of the leftover material (i.e. cell-free extract) that biocatalysed C3 to C4 diol, which adds value to the overall economics of the process using only crude glycerol (C3) itself as a fermentative medium.

Foreign