Efficient glycerol transformation by resting Gluconobacter cells

Abstract

In the present work, glycerol biotransformation using Gluconobacter strains was studied with a process intensification perspective that facilitated the development of a cleaner and more efficient technology from those previously reported. Starting from the industrial by-product, crude glycerol, resting cells of Gluconobacter frateurii and Gluconobacter oxydans were able to convert glycerol under batch reactor conditions in water with no other additive but for the substrate. The study of strains, biomass:solution ratio, pH, growth stage, and simplification of media composition in crude glycerol bioconversions facilitated productivities of glyceric acid of 0.03 g/L.h and 2.07 g/L.h (71.5 g/g % pure by NMR) of dihydroxyacetone (DHA). Productivities surmounted recent reported fermentative bioconversions of crude glycerol and were unprecedented for the use of cell suspended solely in water. This work proposes a novel approach that allows higher productivities, cleaner production, and reduction in water and energy consumption, and demonstrates the applicability of the proposed approach.