Long-term, selective production of caproate in an anaerobic membrane bioreactor. (April 2020)

• Record Type: Journal Article
• Authors: Pan, Xin-Rong; Huang, Liang; Fu, Xian-Zhong; Yuan, Yan-Ru; Liu, Hou-Qi; Li, Wen-Wei; Yu, Lei; Zhao, Quan-Bao; Zuo, Jiane; Chen, Lei; Lam, Paul Kwan-Sing
• Is Part Of: Bioresource technology. Volume 302(2020)
• Publication Date: 2020-04
• Subjects: Caproate production -- Anaerobic membrane bioreactor -- Microbial community -- Acetate to ethanol ratio -- Chain elongation; 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.2020.122865
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Selective caproate production was achieved in an AnMBR. The AnMBR was continuously operated for 522 days. A caproate ratio of 70% was achieved at influent ethanol-to-acetate ratio of 3. Clostridia and Methanobacterium species were substantially enriched. Abstract: Fermentative caproate production from wastewater is attractive but is currently limited by the low product purity and concentration. In this work, continuous, selective production of caproate from acetate and ethanol, the common products of wastewater anaerobic fermentation, was achieved in an anaerobic membrane bioreactor (AnMBR). The reactor was continuously operated for over 522 days without need for chemical cleaning. With an ethanol-to-acetate ratio of 3.0, the effluent caproate concentration was 2.62 g/L on average and the caproate ratio in liquid products reached 74%. Further raising the influent ethanol content slightly increased the effluent caproate level but lowered the product selectivity and resulted in microbial inhibition. The Clostridia (the major caproate-producing bacteria) and Methanobacterium species (which consume hydrogen to alleviate microbial inhibition) was significantly enriched in the acclimated sludge. Our results imply a great potential of utilizing AnMBR to recover caproate from the effluent of wastewater acidogenic fermentation process.