Long-term alkaline volatile fatty acids production from waste streams: Impact of pH and dominance of Dysgonomonadaceae. (February 2022)

• Record Type: Journal Article
• Authors: Owusu-Agyeman, Isaac; Plaza, Elzbieta; Cetecioglu, Zeynep
• Is Part Of: Bioresource technology. Volume 346(2022)
• Publication Date: 2022-02
• Subjects: Alkaline pH -- Sewage sludge -- Organic waste -- Co-fermentation -- Microbial community; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2021.126621
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Co-fermentation of PS & OW enhanced VFA production at pH 10 in a batch study. Long-term study at pH 10 produced VFA up to 30, 300 mgCOD/L but later reduced. VFA production was restored up to 32, 000 mg COD/L by lowering the pH to 9. Acetic acid was most dominant, but propionic acid significantly increased at pH 9. Reducing pH from 10 to 9 shifted microbial community structure to Dysgonomonadaceae. Abstract: Alkaline co-fermentation of primary sludge and external organic waste (OW) was studied to elucidate the influence of substrate ratios and long-term system robustness and microbial community dynamics using batch and semi-continuous reactors. Volatile fatty acid (VFA) production increased with increasing OW fraction in the substrate due to synergistic effects of co-degradation. VFA production at pH 10 increased up to 30, 300 mgCOD/L (yield of 630 mg COD/gVSfed ) but reduced over time to ≈10, 000 mgCOD/L. Lowering pH to 9 led to the restoration of VFA production with a maximum of 32, 000 mg COD/L (676 mg COD/g VSfed ) due to changes in microbial structure. VFA was composed mainly of acetic acid, but propionic acid increased at pH 9. The microbial community was dominated by Bacillaceae (34 ± 10%) and Proteinivoracales_uncultured (16 ± 11%) at pH 10, while Dysgonomonadaceae (52 ± 8%) was enriched at pH 9. The study demonstrated a zero-waste strategy that turns organic wastes into bio-based products.