Influence of the total concentration and the profile of volatile fatty acids on polyhydroxyalkanoates (PHA) production by mixed microbial cultures

Abstract Polyhydroxyalkanoates (PHAs) production from lignocellulosic biomass using mixed microbial cultures (MMC) is a potential cheap alternative for reducing the use of petroleum-based plastics. In this study, an MMC adapted to acidogenic effluent dark fermentation (DF) exhausted sugar beet cossettes (ESBC) has been tested in order determine its capability produce PHAs nine different synthetic mixtures volatile fatty acids (VFAs). The tests consisted acetic, propionic, butyric, and valeric range 1.5–9.0 g/L total acidity with three valeric:butyric ratios (10:1, 1:1, 1:10). Experimental results have shown consistent preference butyric as carbon source instead other shorter (propionic or acetic) terms PHA yield (estimated dry cell weight basis), maximum value 23% w/w. Additionally, valeric-rich demonstrated carry out fast degradation process but poor final compared high mixtures. Finally, initial concentrations (1.1 4.1 g/L) be counterproductive production.