Biosynthesis of poly-?-hydroxyalkanoate by Brevundimonas vesicularis LMG P-23615 and Sphingopyxis macrogoltabida LMG 17324 using acid-hydrolyzed sawdust as carbon source

Silva, J. A.; Tobella L.M.; Martínez M.A.; Becerra, J. ; Godoy, F

Keywords: hydrolysis, acid, performance, growth, polymers, chromatography, biosynthesis, bacteria, gas, flow, salts, nitrogen, acids, liquid, beta, mass, bacterial, polymer, wood, compound, carbon, drug, article, hydroxy, spectrometry, environmental, cytometry, organic, polyesters, plastics, sawdust, proteobacteria, biopolymers, biodegradable, source, mineral, (microorganisms), nonhuman, High, unclassified, Poly, Biodegradation,, phytohemagglutinin, Brevundimonas, vesicularis, Sphingopyxis, macrogoltabida, alkanoic, hydroxyalkanoate, Sphingomonadaceae, Acid-hydrolyzed, Caulobacteraceae


Poly-?-hydroxyalkanoate (PHA) is a biodegradable polymer accumulated in intracellular granules by different bacterial species. Its physical and chemical properties are similar to those of petroleum-derived plastics. Material generated by the acid hydrolysis of wood was evaluated for use in the bacterial synthesis of PHA. Acid-hydrolyzed sawdust was prepared and adjusted to pH 7. Mineral salts with carbon:nitrogen (C:N) proportions of 100:1, 100:3.5, 100:10, 100:30, or 100:50 and trace elements were added and these solutions were inoculated with a bacterial strain Brevundimonas vesicularis LMG P-23615 or Sphingopyxis macrogoltabida LMG 17324. The percentage of cells accumulating PHA was evaluated by flow cytometry. The hydrolyzed sawdust composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). The organic material (601.5 mg l -1) contained 112.5 mg l -1 sugars. Over 96% of these sugars were consumed and more than 90% of the bacterial cells accumulated PHA. The 100:3.5 C:N proportion was optimal for growth and PHA synthesis, with yields ranging from 64% to 72% of the dry cell weight. The results suggest that acid-hydrolyzed sawdust can be used by bacteria as a carbon source for growth and PHA production. This forestry by sub-product offers a low-cost alternative for obtaining biodegradable plastics (e.g., PHA) synthesized by bacteria. © 2007 The Society for Biotechnology, Japan.

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Volumen: 103
Número: 6
Fecha de publicación: 2007
Página de inicio: 542
Página final: 546