RT journal article
T1 Effect of the organic loading rate on the PHA-storing microbiome in sequencing batch reactors operated with uncoupled carbon and nitrogen feeding
A1 Crognale, Simona
A1 Lorini, Laura
A1 Valentino, Francesco
A1 Villano, Marianna
A1 Marzo Gago, Cristina
A1 Tonanzi, Barbara
A1 Majone, Mauro
A1 Rossetti, Simona
A2 Ingeniería Química y Tecnología de Alimentos
K1 Polyhydroxyalkanoates (PHA)
K1 Mixed Microbial Culture (MMC)
K1 Feast and famine regime
K1 Uncoupled C/N feeding
AB Over the last years, in a search for sustainable and biodegradable alternatives to petrol-based plastics, biotechnological applications turned to the potentialities of mixed microbial cultures (MMC) for producing polyhydroxyalkanoates (PHAs). Under a feast and famine regime, an uncoupled carbon (C) and nitrogen (N)-feeding strategy may be adopted by dosing the C-source at the beginning of the feast and the N-source at the beginning of the famine in order to stimulate a PHA storage response and microbial growth. Even though this strategy has been already successfully applied for the PHA production, very few information is to date available regarding the MMC operating in these systems and the influence of Organic Loading Rate (OLR) on their selection and enrichment. To fill the gap, this study investigated the effect of the OLR on the selection of PHA-accumulating microorganisms in a sequencing batch reactor (SBR) operated with an uncoupled C and N feeding strategy. The SBR cycle length was set at 12 h and four OLRs values (4.25, 8.50, 12.75 and 18 gCOD L−1 d−1) were tested by changing the concentration of the feeding solution, made of a synthetic mixture of acetic (85% of the overall COD) and propionic (15%) acids. The PHA-storage yield increased by increasing the OLR (up to 0.69 COD/COD at 12.75 gCOD L−1 d−1) but significantly decreased (0.27 COD/COD) at 18 gCOD L−1 d−1 concomitantly with a longer feast phase and a lower PHA content in the biomass at the end of the feast phase. The selective pressure induced by the applied OLRs strongly influenced the microbiome composition revealing a high content of putative PHA-storing bacteria, such as Rhodobacter, Thauera and Paracoccus, in the SBR operated at OLRs 4.25, 8.50 and 12.75 g COD L−1 d−1 (up to 97.4% of total reads) and a low content (5.4%) in the SBR at 18 g COD L−1 d−1where the predominance of genus Nitrinicola was instead observed.
SN 0048-9697
YR 2022
FD 2022-06-15
LK http://hdl.handle.net/10498/35173
UL http://hdl.handle.net/10498/35173
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 11-nov-2026