Rational flux-tuning of Halomonas bluephagenesis for co-production of bioplastic PHB and ectoine
Hong Ma, Yiqing Zhao, Wuzhe Huang, Lizhan Zhang, Fuqing Wu, Jianwen Ye, Guo‐Qiang Chen
Abstract
Abstract Ectoine, a compatible solute synthesized by many halophiles for hypersalinity resistance, has been successfully produced by metabolically engineered Halomonas bluephagenesis , which is a bioplastic poly(3-hydroxybutyrate) producer allowing open unsterile and continuous conditions. Here we report a de novo synthesis pathway for ectoine constructed into the chromosome of H. bluephagenesis utilizing two inducible systems, which serve to fine-tune the transcription levels of three clusters related to ectoine synthesis, including ectABC , lysC and asd based on a GFP-mediated transcriptional tuning approach. Combined with bypasses deletion, the resulting recombinant H. bluephagenesis TD-ADEL-58 is able to produce 28 g L −1 ectoine during a 28 h fed-batch growth process. Co-production of ectoine and PHB is achieved to 8 g L −1 ectoine and 32 g L −1 dry cell mass containing 75% PHB after a 44 h growth. H. bluephagenesis demonstrates to be a suitable co-production chassis for polyhydroxyalkanoates and non-polymer chemicals such as ectoine.