This project addresses the forestry research need (6) utilization of wood and other forest products. Lignin is the second largest carbon source on earth after cellulose. It is considered waste product and typically burned after cellulose extraction. Considering the high carbon value of lignin, conversion to methane fuel (and other products) would be a much better use of this natural renewable source material. The greatest challenge of biologically converting lignin to methane fuel is the extremely slow rate of microbial degradation of lignin. In general, unaltered lignin conversion to biofuels cannot occur without some manner of pretreatment. Prior studies showed that, when decomposed to much simpler organic molecules of <1,000 Dalton MW, lignin can be converted by microbes to methane under anaerobic conditions. The decomposition of lignin requires caustic physical and chemical conditions such as strong base and high temperature up to 300 degree Celsius. Pretreatment methods that are milder and less energy intensive are highly sought. We propose to treat lignin with acid/base under supercritical CO2 condition which is above 31.1 degree Celsius and 72.9 atmospheric pressures. We will search for optimal supercritical CO2 conditions, will characterize the molecular properties of the decomposed lignin segments, and will measure the methane conversion efficiency for the decomposed lignin. We plan to patent the technologies developed and publish the scientific findings in peer-reviewed journals. Expected Impact: The proposed study meets the current research need of innovative technologies for producing renewable energy from biomass. As the second largest carbon source on earth, lignin is typically left as waste after cellulose conversion to products. The complex aromatic structure of lignin potentially can be harvested for use as chemical feedstock. In addition, it is highly desired to converting lignin into certain forms of biofuel such as methane that can be easily transported and readily utilized. We will develop a combined physical and chemical technique for rapidly decomposing tightly-knit, three dimensional lignin structures to smaller organic molecules that can later be converted by microbes to methane. Compared to the widely used hot water treatment (200-300 degree Celsius), the technique to be developed in this study is milder, faster, and less energy intensive. If it is successfully developed, our technology could potentially overcome the limits of current technologies to break up complex structures of lignin, advancing both technical and scientific frontiers for converting lignin to proper biofuels.
|Effective start/end date||7/1/10 → 6/30/14|
- National Institute of Food and Agriculture (National Institute of Food and Agriculture (NIFA))