Improved Anerobic Digester Biogas Production through the Application of Immobilized Enzymes

Biogas production from waste utilizes a broad range of feedstocks, from agricultural waste to metropolitan sewage. Effective utilization of the available feedstock is necessary to maintain the economic viability and overall sustainability of the digestion. The addition of enzymes has been investigated to improve digestion of difficult materials such as fats and proteins which increases biogas production, reduces total solids at the conclusion of digestion, and actively manages issues with foaming. Recent studies have determined that enzymatic treatment of anaerobic digester feed materials can increase the quality and quantity of biogas generation without the need for additional energy inputs. However, the utility of enzyme supplements is limited as the enzymes are rapidly degraded in the microbially active environment of the digester. Guild BioSciences' patented enzyme immobilization technology, ImmobiZymeâ„¢, can provide an economic and practical solution to improving the survivability of enzyme in digester applications. Immobilized enzymes have demonstrated significantly improved stability and reactivity in aggressive, digestive, or denaturing environments. This combined with the low manufacturing cost of the ImmobiZyme process signifies that an enzymatic solution to improving digester performance is possible.The aim of this project is to evaluate the capability of multiple enzymes, following immobilization through our patented technology, to increase the production of biogas of an anerobic digester consistently and significantly over the course of a 28-day bench-scale test. Results from Phase I will identify the best enzyme candidates and immobilization formulations for a pilot-scale study based on: 1) overall biogas generation, 2) active lifetime of the immobilized enzyme in the reactor, and 3) quantity of enzyme required.