(764d) Polymalic Acid Fermentation: A Platform for Production of Biopolymers and Chemicals

Polymalic acid (PMA) is a novel polyester polymer that has been broadly used in the medical and food industries. Its monomer, L-malic acid, is also a potential C4 platform chemical and extensively used in the food industry while it is currently supplied with the racemic mixture (DL-Malic acid) through chemical synthesis. Recently, great researches have been attempted to develop biotechnological process for L-malic acid production. In our study, a novel route for production of L-malic acid and its derivatives based on PMA platform was developed. Here, a specific fluorescence probe for detecting acidity strength was designed and used for high-throughput screening. Based on the genome-scale metabolic model iZX637, Engineered the strain with overexpressed the gene of pyruvic carboxylase resulted in a PMA titer increase by 30% in shake flask. During the fermentation process, nitrogen limitation was found to be beneficial for PMA biosynthesis, which could upregulate the expression of key genes involved in the PMA biosynthesis pathway. Disruption or overexpression of the nitrogen transcriptional regulator Gat1 controlled by the TOR signaling pathway could obviously regulate PMA biosynthesis. Finally, the downstream process and progress in industry in China are presented.