Clean Technology 2008
F. Freitas, J. Pais, V.D. Alves, M. Carvalheira, N. Costa, R. Oliveira, M.A.M. Reis
Universidade Nova de Lisboa, PT
glycerol-rich product, exopolysaccharide, polyhydroxybutyrate, bioreactor
Glycerol, a byproduct of many industrial processes, mainly in biodiesel production, is generated in quantities far beyond current consumption in traditional applications, thus making it a residue for which interesting applications are lacking. The objective of this work was the conversion of the glycerol-rich byproduct obtained in biodiesel production facilities into biopolymers using a Pseudomonas strain. Two distinct biopolymers were simultaneously produced: an extracellular polysaccharide (EPS) and intracellular polyhydroxybutyrate (PHB). Under optimized EPS production conditions in fed-batch mode, the maximum cellular PHB content was 39 % of CDW and the maximum EPS concentration was 12 g/l. The process is rather versatile since it may be controlled to favor the production of one or both biopolymers. This new process constitutes a promising technology for the valorization of glycerol-rich byproduct, since it accomplishes attractive EPS productivities with relatively low production costs. In addition, the EPS is a novel product with characteristic chemical composition and physical properties which are very competitive when compared to commercially available algal and plant polysaccharides.