Biosynthesis of poly-beta-hydroxyalkanoate by Brevundimonas vesicularis LMG P-23615 and Sphingopyxis macrogoltabida LMG 17324 using acid-hydrolyzed sawdust as carbon source.
Poly-beta-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.
Silva
Johanna A
JA
Laboratorio de Microbiología Básica y Biorremediación, Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160-C, Concepción, Chile.
Tobella
Lorena M
LM
Becerra
José
J
Godoy
Félix
F
Martínez
Miguel A
MA
D000143:Acids; D001673:Biodegradation, Environmental; D001704:Biopolymers / Q000096:biosynthesis*; D002244:Carbon / Q000378:metabolism; D042063:Caulobacteraceae / Q000378:metabolism*; D006868:Hydrolysis; D006880:Hydroxy Acids / Q000378:metabolism*; D011091:Polyesters / Q000378:metabolism*; D042301:Sphingomonadaceae / Q000378:metabolism*; D014934:Wood
D000143:Acids; D001704:Biopolymers; D006880:Hydroxy Acids; D011091:Polyesters; D002244:Carbon