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 from dark fermentation (DF) of exhausted sugar beet cossettes (ESBC) has been tested in order to determine its capability to produce PHAs from nine different synthetic mixtures of volatile fatty acids (VFAs). The tests consisted of mixtures of acetic, propionic, butyric, and valeric acids in the range of 1.5–9.0 g/L of total acidity and with three different valeric:butyric ratios (10:1, 1:1, and 1:10). Experimental results have shown a consistent preference of the MMC for the butyric and valeric acids as carbon source instead other shorter acids (propionic or acetic) in terms of PHA production yield (estimated in dry cell weight basis), with a maximum value of 23% w/w. Additionally, valeric-rich mixtures have demonstrated to carry out a fast degradation process but with poor final PHA production compared with high butyric mixtures. Finally, high initial butyric and valeric concentrations (1.1 g/L and 4.1 g/L) have demonstrated to be counterproductive to PHA production.
Highlights
Polyhydroxyalkanoates (PHAs) are bio-polyesters synthesized intracellularly by some microorganisms
This study reveals the existence of some counterproductive limits to PHA production by mixed microbial cultures (MMC) linked to the presence of high concentrations of valeric and butyric acids
The diminishing does not occur in the same way for tests that have the same valeric:butyric ratio but different total volatile acidity concentration
Summary
Polyhydroxyalkanoates (PHAs) are bio-polyesters synthesized intracellularly by some microorganisms. Its main function is to serve as a carbon and energy reserve in stressful situations in which the growth of microorganisms is unfavorable (inadequate balance of nutrients, scarcity of carbon sources, heat stress, etc.) [1, 2] Their main practical application is based on the fact that they present physical properties similar to certain plastics derived from petroleum. For this reason, there is a growing interest in the industrial sector for their production since they are precursors of plastics with excellent biocompatibility characteristics and biodegradability [3]. They are pure compounds in relation to their enantiomeric structure; are non-toxic and biocompatible; have a high crystallinity degree
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
