Enrichment of Microbial Communities for Biogas Production in High-Solids Environments

EPA Grant Number: SU835688
Title: Enrichment of Microbial Communities for Biogas Production in High-Solids Environments
Investigators: Simmons, Christopher W
Institution: University of California - Davis
EPA Project Officer: Hahn, Intaek
Phase: I
Project Period: August 15, 2014 through August 14, 2015
Project Amount: $14,473
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2014) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Energy , P3 Awards , Sustainability

Description:

We propose laboratory experiments to enrich, characterize, and preserve a microbial community capable of high-solids anaerobic digestion (AD) for biorenewable methane production from manure. Use of methane generated via AD has the ability to reduce carbon emissions from fossil-fuel-based energy production by offsetting use of fossil fuels. One of the current limitations of AD technology is a result of low-solids loading within the digester. Increasing the solids content within an anaerobic digester has the potential to decrease water usage, decrease installation costs, decrease energy costs, and increase the feasibility for widespread use of this technology. While many digesters are capable of handling increased solids, the microbial community responsible for methane production can be significantly inhibited and in some cases the sub-community responsible for methane production is lost altogether. This proposed project aims to rectify these digester problems at the level of the microbial community used within the digester through enrichment techniques.

Objective:

The goal of this project is to improve anaerobic digestion of manure in high-solids conditions through development and characterization of a digester microbial community adapted to a low moisture environment and to stabilize this community to facilitate distribution and rapid start-up of manure digesters. The broader objectives of this work are to improve biomethane production from manure and to broaden and simplify the adoption of high-solids anaerobic digestion of manure for bioenergy production.

Approach:

Project objectives will be accomplished by 1) enriching for anaerobic communities that are capable of rapid hydrolysis and methanogenesis under thermophilic, high-solids conditions using manure as a feedstock, 2) developing a preservation protocol for these communities, and 3) characterizing the phylogenetic composition and anaerobic digestion performance of the enriched communities prior to and following stabilization. Specifically, the preserved communities will be examined for performance characteristics, such as biogas quality, production rates, and yield. Further analysis of the microbial community will entail DNA extraction and sequencing analysis to elucidate key organisms responsible for both the methanogenic and hydrolytic activity under high-solids conditions and provide data for future community development.

Expected Results:

This project is expected to result in an enriched microbial community ideal for high-solids, thermophilic anaerobic digestion of manure. Additionally, a preservation protocol will be developed such that the digester community can be stored long-term with no loss in performance to facilitate distribution to end-users. The community profile will be analyzed using 16S rRNA gene sequencing for taxonomic profiling. This information will inform future studies and provide phylogenetic metrics for potentially assessing digester performance, stability, and inhibition.

Supplemental Keywords:

renewable energy, biofuels, waste management, sustainability

Progress and Final Reports:

  • Final