Construction of a conjugation method for the transformation of Cobetia sp. IU180733JP01 (5-11-6-3) that accumulates poly(3-hydroxybutyrate) from seaweeds.

Cobetia bacteria are considered useful hosts for industrial applications owing to their fast growth, high cell density, and halophilicity. Here, we constructed an efficient conjugation method to obtain Cobetia sp. IU180733JP01 (5-11-6-3) transformants, which can produce bioplastics from alginate or seaweed waste. Lysogeny Broth medium containing 2% NaCl was used to co-cultivate the 5-11-6-3 strain (plasmid recipient) with Escherichia coli S17-1 (plasmid donor). Transformants with the highest conjugation efficiency [(2.92 ± 1.37) × 10^-3] were obtained at a donor:recipient cell number ratio of 5:1. This is the first study reporting the creation of recombinant strains in the genus Cobetia. This method will contribute to creating a platform strain for the production of bioplastics and other useful materials from marine biomass.