Novel Poly[(R)-3-Hydroxybutyrate]-Producing Bacterium Isolated from a Bolivian Hypersaline Lake

Alejandra Rodriguez-Contreras1, Martin Koller2, Miguel Miranda de Sousa Dias2, Margarita Calafell3, Gerhart Braunegg2 and María Soledad Marqués-Calvo1*

1Department of Optics and Optometry, Technical University of Catalonia, Sant Nebridi 22, ES-08222 Terrassa, Barcelona, Spain
2Institut of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12, AT-1-8010 Graz, Austria
3Department of Chemical Engineering, Technical University of Catalonia, Colom 1, ES-08222 Terrassa, Barcelona, Spain

Article history:

Received September 6, 2011
Accepted July 20, 2012

Key words:

poly[(R)-3-hydroxybutyrate], biopolymer, bioproduction, new strain, hypersaline environment, thermal properties


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.  

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