A novel higher polyhydroxybutyrate producer Halomonas halmophila 18H with unique cell factory attributes

For cost-competitive biosynthesis of polyhydroxybutyrate (PHB), the screening of efficient producers and characterization of their genomic potential is fundamental. In this study, 94 newly isolated halophilic strains from Turkish salterns were screened for their polyhydroxyalkanoates (PHAs) biosynthesis capabilities through fermentation. Halomonas halmophila 18H was found to be the highest PHB producer, yielding 63.72 % of its biomass as PHB. The PHB produced by this strain was physically and chemically characterized using various techniques. Its genome was also sequenced and found to be large (6,713,657 bp) and have a GC content of 59.9 %. Halomonas halmophila 18H was also found to have several copies of PHB biosynthesis genes, as well as 20 % more protein-coding genes and 1075 singletons compared to other high PHB producers. These unique genomic features make it a promising cell factory for the simultaneous production of PHAs and other biotechnologically important secondary metabolites.