resumo
Pulp and paper factories produce several residues that can be explored and valorized through poly-hydroxyalkanoate (PHA) production via a three-step process. The objective of this work was focused on the selection step. Acidified hardwood spent sulfite liquor (HSSL), a fermented waste stream from a pulp and paper factory, was used to select a mixed microbial culture (MMC) in a sequencing batch reactor (SBR) operated for 156 days under different operational conditions. The MMC adapted to the imposed conditions, revealing its robustness whenever the operational parameters were changed. Feast-to-Famine ratio was kept below or equal to 0.2, with constant production of a copolymer of P(3HB-co-3 HV), and with storage contents values over 30 %. Changes in the operational conditions, namely cycle length, and organic load rate (OLR), successfully led to the selection of an MMC with a stable accumulation capacity and an increased biomass concentration. Next Generation Sequencing analysis was performed on samples collected during the SBR operational period. The analysis of the microbial composition of the MMC showed a rise in PHA-accumulating bacteria over time. Acidovorax and Comamonas species were found mainly to drive the PHA storage process during the first two periods of operation. After an increase in the OLR, in the last period, a shift towards Comamonas dominance occurred, suggesting a higher tolerance to the inhibitory compounds of the HSSL for this genus.
palavras-chave
BIODEGRADABLE POLYMER PRODUCTION; SEQUENCING BATCH REACTOR; COMAMONAS SP B-9; ACTIVATED-SLUDGE; WASTE-WATER; POLYHYDROXYALKANOATES PHAS; ACCUMULATING BACTERIA; MILL EFFLUENT; FATTY-ACIDS; STORAGE
categoria
Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology
autores
Pereira, J; Queiros, D; Lemos, PC; Rossetti, S; Serafim, LS
nossos autores
Joana Sofia Marques Pereira
Estudante de doutoramento
Luísa Seuanes Serafim
Professor Auxiliaragradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2019) and LAQV-Associate Laboratory for Green Chemistry (Ref. FCT UID/QUI/50006/2019), financed by national funds through the FCT/MCTES and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. Paulo C. Lemos acknowledges the support by FCT/MCTES for contract IF/01054/2014/CP1224/CT0005. Diogo Queiros and Joana Pereira thank FCT/MCTES for their PhD grants, SFRH/BD/87758/2012 and SFRH/BD/130003/2017, respectively.