Very recently, we have developed a new and effective technique to biotechnologically produce glyceric acid (GA) from glycerol. GA is expected to be one of the promising glycerol derivatives, such as a multifunctional monomer, a pharmaceutical and cosmetic material. Here, we report the microbial production of GA from raw glycerol and the development of GA-based polymers.
First, we searched for GA-producing strains among acetic acid bacteria and investigated the productivity of GA by the selected strains. We found that some strains belonging to Gluconobacter sp. efficiently converted glycerol to GA at a yield of about 137 g/L and Acetobacter tropicalis selectively produced D-GA from glycerol. In addition, a novel branched-type poly(lactic acid) (PLA) was synthesized by polycondensation of lactide in the presence of GA. The resulting branched PLA had lower crystallinity and glass transition temperatures than those of the conventional linear PLA, and the melting point of the branched PLA disappeared. Moreover, by a blend of the branched polymer, the crystallization of the linear PLA was accelerated at a lower temperature. The present branched PLA containing GA should thus have potential as a novel bio-based modifier for PLA.