Anaerobic digesters (AD) are bioprocessor converting organic or inorganic chemical energy into methane gas and widely being used for wastewater treatment processes. Microbial fuel cells (MFCs) are bioelectrochemical systems that convert chemical energy contained in organic matter into electrical energy by using the catalytic (metabolic) activity of living microorganisms. In the current study, mediator-less two chamber H-type MFCs were constructed using dairy AD solution as anode inocula pursuing both biomethane production and electricity generation from finely ground pine tree (Avicel). AD-MFCs were placed at 32oC and after the circuit voltage was stabilized on d9, bovine rumen fluid enriched in cellulose broth media through 3 sequential subcultures was added to treatment group of AD-MFC at 1% v/v dosage, while control group received aseptic pure broth media used for treatment preparation. AD-MFC power and current across an external resistor were measured daily for 9d. At the end of operation on d9, biogases collected in connected Mylar balloon were analyzed for volume and composition. Addition of enriched cellulolytic rumen microorganisms to AD-MFC increased methane gas production and electricity generation. In control AD-MFCs, power density normalized to anode surface area were maintained between 16 and 19 mW/m2, and biomethane and CO2 production were 181 and 76mL, respectively. Power density in rumen fluid added AD-MFC increased (P &lt; 0.0001) with incubation time and value was 15.4 mW/m2 at d0 and 65.3 mW/m2 at d9. In rumen fluid added AD-MFC, biomethane and CO2 production were 406 and 210mL, respectively. These observations imply that consolidation of AD and MFC may be a new strategy for renewable bioenergy production, and biocatalysis in AD-MFCs requires additional cellulolytic activities such as rumen microbial cellulolysis to utilize structural biomass in bioenergy production.

Renewable bioenergy production in the consolidated anaerobic digester and microbial fuel cell with cellulolytic rumen fluid inoculation

254th National Meeting (2017)

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