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Poly[(R)-3-hydroxybutyrate] (PHB) constitutes a biopolymer synthesized from renewable resources by various microorganisms. This work focuses on finding a new PHB-producing bacterium capable of growing in conventional media used for industrial biopolymer production, its taxonomical identification, and characterization of its biopolymer. Thus, a bacterial isolation process was carried out from environmental samples of water and mud. Among the isolates, strain S29 was selected and used in a fed-batch fermentation to generate a biopolymer. This biopolymer was recovered and identified as PHB homopolymer. Surprisingly, it featured several fractions of different molecular masses, and thermal properties unusual for PHB. Hence, the microorganism S29, genetically identified as a new strain of Bacillus megaterium, proved to be interesting not only due to its growth and PHB accumulation kinetics under the investigated cultivation conditions, but also due to the thermal properties of the produced PHB., Poli[(R)-3-hidroksibutirat] (PHB) je biopolimer kojega sintetiziraju različiti mikroorganizmi iz obnovljivih izvora. Težište je rada bilo na pronalasku novog soja bakterije koji može proizvesti PHB na različitim industrijskom podlogama, te provesti taksonomsku identifikaciju soja i karakterizaciju biopolimera. Stoga su iz uzoraka vode i mulja izolirani sojevi bakterija, te je šaržnim postupkom fermentacije s pritokom supstrata pomoću odabranog soja S29 proizveden biopolimer, kasnije određen kao homopolimer PHB. Iznenađujuće je što je biopolimer imao više frakcija različitih molekularnih masa i termička svojstva neuobičajena za PHB. Time je potvrđeno da je novi soj bakterije Bacillus megaterium S29 zanimljiv ne samo zbog kinetičkih značajki rasta i akumulacije PHB, već i zbog termičkih svojstava proizvedenog biopolimera.