title: Mixed culture polyhydroxyalkanoates production from sugar molasses: the use of a 2-stage CSTR system for culture selection.
abstract: Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers. The use of mixed microbial cultures (MMC) and low cost feedstocks have a positive impact on the cost-effectiveness of the process. It has typically been carried out in Sequencing Batch Reactors (SBR). In this study, a 2-stage CSTR system (under Feast and Famine conditions) was used to effectively select for PHA-storing organisms using fermented molasses as feedstock. The effect of influent substrate concentration (60-120 Cmmol VFA/L) and HRT ratio between the reactors (0.2-0.5h/h) on the system's selection efficiency was assessed. It was shown that Feast reactor residual substrate concentration impacted on the selective pressure for PHA storage (due to substrate-dependent kinetic limitation). Moreover, a residual substrate concentration coming from the Feast to the Famine reactor did not jeopardize the physiological adaptation required for enhanced PHA storage. The culture reached a maximum PHA content of 61%. This success opens new perspectives to the use of wastewater treatment infrastructure for PHA production, thus valorizing either excess sludge or wastewaters.
authors.affiliation: CQFB-Requimte, FCT-UNL, 2829-516 Caparica, Portugal.
authors.forename: M G E
authors.initials: MG
authors.lastname: Albuquerque
authors.forename: S
authors.initials: S
authors.lastname: Concas
authors.forename: S
authors.initials: S
authors.lastname: Bengtsson
authors.forename: M A M
authors.initials: MA
authors.lastname: Reis
mesh_terms: D001420:Bacteria, Aerobic / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018920:Coculture Techniques / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008965:Molasses / Q000382:microbiology*; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D013400:Sugar Acids / Q000378:metabolism*
chemical_list: D054813:Polyhydroxyalkanoates; D013400:Sugar Acids