A novel process for bioglycerol (C3) upgradation to 2,3-butanediol (C4)
by cell free extracts of E. aerogenes NCIM 2695
Abstract
Production of chemicals from renewable bio-resources is a green and
starring approach, which serves as a substitute to petroleum
derivatives. Bioglycerol, a C3 triol 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. Upgradation
of bioglycerol to C4 diol such as 2,3-butanediol (2,3-BDO) alongwith
formation of 1,3-propanediol, acetoin is one of the best alternatives of
glycerol value valorization as these products are amongst top
biorefinery platform chemicals. Previously, we have reported bioglycerol
conversion to 2,3 BDO conversion in 120 h using cell pellets of mixed
cultures. While attempting a step closer to “Circular Economy” concept
we then focused on utilizing by-product of the process leading to zero
waste. Our screening studies showed that cell free extracts of
Enterobacter aerogenes NCIM 2695 produced 22 g/L 2,3-BDO from glycerol
as a sole source of carbon, within 96 h. Further, glycerol dehydrogenase
activity combined with protein analysis depicted cell bound nature. This
study offers a faster and effective utilization of cell free extract in
the form of supernatant for biocatalysing C3 upgradation to C4 diol
which significantly contributes to overall economics of the process
using crude glycerol as a sole source of carbon (C3) and serves as an
simple, and cost effective fermentative medium.