Bio transformation of glycerol to 3 hydroxypropionic acid using lactobacillus reuteri

Abstract

3-hydroxypropionic acid (3-HP) is one of the US DOE listed newlinebiomass derivable platform chemicals. Anti-microbial properties of 3-HP, newlineapplications of its polymer in bio-medical implants and regulators restrictions newlineon E. coli derived chemicals for infant and food applications demands 3-HP newlineproduction from a GRAS host. Production of 3-HP from Lactobacillus reuteri newlineis attaining interest nowadays on these grounds. L. reuteri encompasses coenzyme newlineA dependent 3-HP production pathway and the enzymes are encoded newlineby the pdu operon. Where growing cells demand carbon and energy for newlinebiomass production, resting cells can potentially exploit their same newlinemetabolism more proficiently for redox reactions providing higher specific newlineactivities and product yields on energy source. Microbial chassis design newlinebased on resting cells has been proven to be a successful approach for many newlinebio-transformations.When Lactobacillus reuteri was grown in various glucose and newlineglycerol ratios in MRS broth, 3-HP production was not detected by HPLC. In newlineorder to understand, whether the glycerol flux was flowing into the byproducts newlineinstead of 3-HP, carbon balancing exercise was carried out. A semi newlinedefined media for Lactobacillus developed earlier was modified for the newlinecarbon balancing experiments by addition of supplements so that L. reuteri newlinewas able to grow up to an optical density of two. A carbon closure of ~ 96% newlinewas achieved within the glycerol conversion to reuterin and 1,3-PD in glucose newlineand glycerol co-fermentation. Such closure validates the absence of parallel newlineoxidation of glycerol to dihydroxyacteone through glycerol dehydrogenase newlinepathway present in other few Lactobacillus and Klebsiella species. newline newline newline