Abstract Vinasse is the main liquid waste of the ethanol industry and its valorization by a bioprocess as a substrate for production of a value-added product contributes to the ethanol process. This work aimed to study the possibility to use vinasse for poly(3-hydroxybutyrate) (PHB) production by Cupriavidus necator. The growth of C. necator was evaluated using different vinasse concentrations and no inhibitory effect was observed. Cultivations in a bioreactor were carried out with pure vinasse, vinasse with nitrogen and vinasse with nitrogen and mineral salts. The best values of total biomass (5.1 g.L-1) and PHB (26% of total biomass) were obtained in the cultivation with nitrogen and salts added. The results indicated that vinasse could be used for PHB production. However, vinasse should be used in association with another substrate, aiming to improve the production. This is the first report on vinasse valorization for PHB production by C. necator.

Resumo A extração de poli(3-hidroxibutirato) (P(3HB)) com a utilização de solventes tóxicos e voláteis é contraditória à ideia do emprego destes biopolímeros para minimizar as agressões ambientais causadas pelos polímeros petroquímicos. O carbonato de propileno (CP) possui baixa toxicidade e alto ponto de ebulição, o que garante baixo risco de perdas por evaporação e alto rendimento de recuperação, podendo assim ser reutilizado. O objetivo deste trabalho foi verificar o efeito da reutilização do CP, recuperado do processo de extração de P(3HB) produzido por Cupriavidus necator, no rendimento e pureza do biopolímero e avaliar as perdas de solvente durante as etapas do processo de extração. Verificou-se a possibilidade de recuperar 80% do CP ao longo do processo. O solvente recuperado foi reutilizado onze vezes sem perder sua eficiência no rendimento e na pureza do produto. Desta forma, o presente estudo propõe a reutilização do CP, no processo de extração de P(3HB), contribuindo assim para a redução dos custos de produção deste biopolímero.

Abstract Poly(3-hydroxybutyrate) (P(3HB)) extraction using toxic volatile solvents is contradictory to the idea of using this biopolymer to minimize environmental aggressions caused by petrochemical polymers. Propylene carbonate (PC) has low toxicity and high boiling point, which ensure a low risk of losses due to evaporation and high recovery performance, allowing for reuse. The aim of this study was to investigate the effect of reusing PC recovered the process of extraction of P(3HB) produced by Cupriavidus necator on the performance and purity of the biopolymer and evaluate the amount of solvent loss during the stages of the extraction process. It was observed that 80% of PC could be recovered throughout the process. The recovered solvent was reused eleven times without losing its efficiency in terms of product performance and purity. Hence, the present study proposes to reuse PC in the process of P(3HB) extraction, thus contributing to reduce the costs for the production of this biopolymer.