Bolivian bacteria finding has future bioplastic potential

Bacteria from Salar de Uyuni in Bolivia conceal bioplastic
Bacteria from Salar de Uyuni in Bolivia conceal bioplastic

Related tags Bacteria Microbiology

A microorganism that produces and stores poly-beta-hydroxybutyrate (PHB), a biodegradable compound, has been discovered by scientists.

Researchers from the Polytechnic University of Catalonia (UPC) found the bacterium stores large amounts of PHB, a polymer used in the production of bioplastics in industries including packaging.

The bacterium is Bacillus megaterium Uyuni S29, a strain that produces the largest amount of polymer of the genus.

Researchers found it featured several fractions of different molecular masses, and thermal properties unusual for PHB.

It has been found in the water 'eyes' of the Salar de Uyuni or Uyuni salt flat, in Bolivia.

Industry similarity

Scientists from the UPC and the Graz University of Technology in Austria have made the bacillus produce the compound in the laboratory in cultivation conditions similar to those used in industry.

However, they recognised the costs of producing biopolymers are "still high and not competitive when compared with conventional polymers, although progress is being made in this regard​."

The technique is published in the journals Food Technology & Biotechnology​ and Journal of Applied Microbiology​.

The team reduced PHB's high molecular weight for the first time, using lipase enzymes, which break up fats, as well as using the biopolymer to form nano- and microspheres loaded with antibiotic to control their spread throughout the organism.

Available for cultivation

Rodríguez-Contreras et al said the importance of this work is the discovery of a strain from environmental samples available for cultivation in a conventional medium with low salt content which is already used in the industrial production of PHAs.

The biosynthesised PHB features thermal properties differing from conventional PHB (lower crystallinity, glass transition temperature and melting point) probably due to polymer fractions of different molecular masses, said the researchers.

They added that further studies are needed in order to optimise the biopolymer production process and to assess the potential of the material for different applications.

"These are very extreme environments, which facilitate intracellular accumulation of PHB, a reserve material used by bacteria in times when nutrients are scarce​," Dr Marisol Marqués, microbiologist at the Polytechnic University of Catalonia (UPC, Spain), explained to SINC (The Scientific Information and News Service).

"The resulting biopolymer has thermal properties different from conventional PHBs, which makes it easier to process, independently of its application,"​ he added.

Source: Journal of Applied Microbiology

Online ahead of print DOI: 10.1111/jam.12151

High production of poly(3-hydroxybutyrate) from a wild Bacillus megaterium Bolivian strain”

Authors: Rodríguez-Contreras A, Koller M, Miranda-de Sousa Dias M, Calafell-Monfort M, Braunegg G, Marqués-Calvo MS

Related topics Processing & Packaging

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