Biopolymers production by Halomonas boliviensis in an integrated biorefinery

Abstract

The main aim of this Thesis is to develop processes that allow the integrated production of biopolymers into biorefineries, using feedstocks from first and second generation as raw materials. The basic nutritional requirements for growth and polyhydroxyalkanoate (PHA) accumulation with the bacterium Halomonas boliviensis were firstly determined. Besides, an analytical methodology based on flow cytometry was developed for a faster quantification of the PHA content. Two different substrates from first generation feedstocks, cereal and sugarcane juice, were evaluated as carbon source for PHA production by H. boliviensis. A novel process configuration was implemented and evaluated, based on the strategy of simultaneous saccharification and fermentation, for the PHA production from cereal mash. Finally, the utilization of volatile fatty acids, derived from residual streams, was evaluated as carbon source. This allowed to upgrade the biorefinery concept. To sum up, the results of this Thesis provide different routes for the formulation of processes that allow the integration of the biopolymers production into a biorefinery and, particularly, information about the general PHA accumulation capacity of H. boliviensis and its specific performance growing on complex carbon sources.