Methanogenesis and Anaerobic Digestion

Fundamental and applied research to improve all stages of anaerobic digestion and methanogenesis

A lab-scale OpenCEL unit

Human society generates enormous quantities of waste organic solids:  e.g., from animal husbandry, food and beverage manufacture, pulp and paper processing, microalgae-based bioenergy, and primary and waste activated sludge from municipal sewage treatment.  Biological stabilization of these enormous quantities of solids brings about major benefits:  reducing the amount of solids for disposal, protecting public health, and capturing the energy and nutrients in the solid biomass.  One biological process is core for all these goals.  It is anaerobic digestion, which naturally integrates four anaerobic microbial processes:  hydrolysis of particulate biomass; fermentation of the hydrolysis products to organic acids and hydrogen gas; generation of acetate from larger organic acids; and methane generation from acetate and hydrogen.  The last step of methanogenesis is carried out by Euryarchaea, which have unique phylogenetic, physiological, and metabolic characteristics.  Methanogenesis is a mature technology that can achieve these important goals today; we seek to improve its performance and the scope of its application.

The Swette Center researchers focus on fundamental and applied research questions of anaerobic digestion.  The Center research begins with the normally rate-limiting step:  hydrolysis.  We pay special attention to pre-treatment of the organic solids, such as with OpenCEL’s Focused Pulsed (FP) technology, which employs high voltage pulses to disrupt the biomass.  Another Center emphasis is on beneficial co-digestion of complementary wastes (e.g., pig manure and paper sludge or microalgae and waste activated sludge).  In all its work on enhancing methanogenesis, Swette Center researchers use advanced tools of molecular biology to identify and track the key microorganisms in a healthy anaerobic microbial food web.  The anaerobic digestion team also links directly with other research themes, such as process modeling, nutrient recovery, microbial electrochemical cells, and the human intestinal microbiota. 


An illustration of the anaerobic food web

A bench-scale anaerobic digester