Solid-state fermentation (SSF) has recently been proposed as an alternative to submerged fermentation for the production of poly(hydroxyalkanoates). In the present work, X-ray diffraction, differential scanning calorimetry, nuclear magnetic resonance and infrared spectroscopy were employed to investigate the chemical structure, as well as the thermal properties and the crystalline morphology of poly(3-hydroxybutyrate) samples produced by SSF, using as raw material either soy cake or soy cake supplemented with 2.5% (m/m) sugarcane molasses. The results obtained showed that the biopolymer obtained by SSF presented the same properties as commercial PHB, except for the higher molar mass and the lower degree of crystallinity that were observed. Thus, the present data indicate that solid-state fermentation is an interesting alternative for the production of PHB, allowing the production of biopolymers with adequate properties from low-cost, renewable resources. (c) 2006 Elsevier Ltd. All rights reserved.