Heterologous production of cyanophycin withTatumella morbiroseicyanophycin synthetase

Microbial production of biopolymers represents a promising, sustainable alternative to current approaches for plastic production. Cyanophycin synthetase 1 (CphA1) produces cyanophycin - an attractive biopolymer consisting of a poly-L-aspartic acid backbone decorated with L-arginine side groups. In this work, a series of CphA1 enzymes from different bacteria were screened for heterologous cyanophycin production in engineered Escherichia coli , from which it was found that CphA1 from Tatumella morbirosei ( Tm CphA1) was especially productive. Tm CphA1 was capable of supporting up to ~2-fold greater yields of insoluble cyanophycin than any other tested CphA1 enzymes, including 10.8-times more than CphA1 from Synechocystis sp. PCC6308. Finally, using a bench-scale bioreactor, cyanophycin production by Tm CphA1-expressing E. coli reached up to 1.9 g per liter of culture by 48 h.