Marine Bacteria Associated with the Green Seaweed Ulva sp. for the Production of Polyhydroxyalkanoates

The biosynthesis of polyhydroxyalkanoate (PHA) biopolymers from certain marine microbes, associated with green macroalgae Ulva sp., has attracted significant attention. The Ulva sp. is abundant biomass in numerous locations around the world and could be easily cultivated by marine farming. The variety of sugars found in Ulva sp. homogenate could be used as a carbon source for microbial growth and PHA production. In this work, we isolated and explored a series of bacterial strains that function as potential producers of P(3HB), utilizing a range of common sugars found in Ulva sp. Analysis of 16S rDNA gene-sequence revealed that the PHA-producing bacteria were phylogenetically related to species of the genus Cobetia, Bacillus, Pseudoaltermonas, and Sulfito-bacter. The highest-yield of P(3HB) was observed in the case of new Cobetia strain, C. amphilecti, with up to 61% (w/w) in the presence of mannitol and 12% (w/w) on Ulva sp. acid hydrolysate as a substrate.