Bacterial strain for synthesizing poly (3-hydroxybutyrate-co-4-hydroxybutyrate) as well as construction method and application of bacterial strain

The invention discloses a bacterial strain for synthesizing poly (3-hydroxybutyrate-co-4-hydroxybutyrate) as well as a construction method and application of the bacterial strain. The construction method comprises the following steps: S1, amplifying three gene sequences of gadB *, gabT and yqhD in vitro; s2, inserting the three gene sequences into a vector to obtain a vector plasmid; and (S3) transferring the vector plasmid obtained in the step (S2) into a Halomonas lutescens MDF-9 competent cell. The invention provides a novel P34HB synthesis pathway, and on the basis that the MDF-9 strain has a P3HB synthesis pathway, a metabolic pathway for synthesizing P4HB by using glutamic acid as a precursor compound is added by utilizing genetic engineering, so that the purpose of producing P34HB is achieved. The engineering bacterium can effectively reduce the price of raw materials in a P34HB production process in the field of PHA, reduce the toxicity risk and improve the production efficiency. 本发明公开了一种合成聚(3-羟基丁酸酯-c