Anaerobic granule-based biofilms formation reduces propionate accumulation under high H2 partial pressure using conductive carbon felt particles

• Published in: Bioresource technology 2016-09, Vol.216, p.677-683
• Main Authors: Xu, Heng, Wang, Cuiping, Yan, Kun, Wu, Jing, Zuo, Jiane, Wang, Kaijun
• Format: Article
• Language: English
• Subjects: Anaerobiosis; Biofilms; Biofuels; Biological Oxygen Demand Analysis; Bioreactors - microbiology; Biotechnology - instrumentation; Biotechnology - methods; Carbon; Clostridium - metabolism; Co-digestion; Direct interspecies electron transfer (DIET); Electron Transport; Geobacter - metabolism; Granule-based biofilms; H2 interspecies transfer (HIT); Hydrogen; Methane - metabolism; Microbial Consortia; Partial Pressure; Propionate accumulation; Propionates - metabolism; Syngas
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.06.010

[Display omitted] •Syngas based co-digestion for overall biogas production enhancement was proposed.•Anaerobic granule-based biofilms alleviated H2-induced propionate accumulation.•Two different anaerobic granule-based biofilms were formed in the ASBR.•Both HIT and DIET pathways might be involved in high-rate propionate degradation. Syngas based co-digestion is not only more economically attractive than separate syngas methanation but also able to upgrade biogas and increase overall CH4 amount simultaneously. However, high H2 concentration in the syngas could inhibit syntrophic degradation of propionate, resulting in propionate accumulation and even failure of the co-digestion system. In an attempt to reduce propionate accumulation via enhancing both H2 interspecies transfer (HIT) and direct interspecies electron transfer (DIET) pathways, layered granule-based biofilms induced by conductive carbon felt particles (CCFP) was employed. The results showed that propionate accumulation was effectively reduced with influent COD load up to 7gL−1d−1. Two types of granule-based biofilms, namely biofilm adhered to CCFP (B-CCFP) and granules formed by self-immobilization (B-SI) were formed in the reactor. Clostridium, Syntrophobacter, Methanospirillum were possibly involved in HIT and Clostridium, Geobacter, Anaerolineaceae, Methanosaeta in DIET, both of which might be responsible for the high-rate propionate degradation.