Production and Characterization of Poly(3-Hydroxybutyrate) from Oleic Acid by Ralstonia eutropha

Vitor Henrique Grigull¹, Delne Domingos da Silva¹, Michele Cristina Formolo Garcia^1,2, Sandra Aparecida Furlan¹, Ana Paula Testa Pezzin¹, Andréa Lima dos Santos Schneider¹* and Gláucia Falcão Aragão<sup>2

1</sup>Laboratory of Biotechnology, University of Joinville Region, Santa Catarina, BR-89201-972 Brazil
²Federal University of Santa Catarina, Florianópolis, BR-88800-000 Brazil

Article history:
Received August 23, 2006
Accepted June 25, 2007

Key words:
biopolymers, Ralstonia eutropha, oleic acid, characterization

Summary:
The aim of this research is to investigate the influence of oleic acid concentration on the cell growth and the physical properties of the polymer formed by cultures of Ralstonia eutropha in mineral medium. Cells were cultivated in Erlenmeyer flasks with 300 mL of mineral medium, containing glucose and fructose as a carbon source (30 g/L) and ammonium sulphate (5.0 g/L) as a nitrogen source. Oleic acid was added as nutritional supplement in different concentrations (0, 0.3, 0.9, 1.5 and 3.0 g/L) and the cells were incubated at 30 °C and 150 rpm. The films prepared by casting were evaluated by X-ray diffraction, thermogravimetry and differential scanning calorimetry. These results indicate that the increase of oleic acid concentrations leads to a higher specific growth rate and cell productivity. The characterization of the films revealed that the increase of the concentration of oleic acid from 0 to 1.5 g/L has no influence on thermal behaviour and crystallinity degree. However, the thermal stability, melting temperature, glass transition temperatures and crystallinity degree decreased when 3.0 g/L of oleic acid were used.

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