13-01: Mechanism based technology for pretreating agricultural residues to produce advanced biofuels

Using existing agricultural residues as biomass feedstock offers near-term opportunity for the development of advanced biofuel and bioproducts. The lack of energy efficient and cost effective technologies that liberate sugars from the plant cell walls remains a major technical barrier for biofuel commercial reality.  Current study, aims at developing an innovative pretreatment technology for using agricultural residues to produce advanced biofuels. As a combined pretreatment process of ozone and soaking aqueous ammonia (OSAA), this technology is based on the understanding of reaction mechanisms of ozone and ammonia with lignocellulose structure. This pretreatment process takes advantage of ozone which is a highly reactive oxidant, targets predominantly lignin, and ammonia which specifically acts on cellulose fibers. The advantages of this process include (1) operating at low temperature and pressure, (2) generating negligible concentrations of inhibitors for downstream applications, (3) producing a single stream of (C6 and C5) sugars, and (4) being environmentally friendly. This approach is suitable for pretreating biomass for advanced biofuels feedstock such as microbial lipids from oleaginous yeast.  The OSAA technology has been tested for maximum sugar release at laboratory scale and its application for yeast fermentation to produce lipid as the feedstock for drop-in fuels have been developed. Our results showed the biomass obtained can be hydrolyzed at high solid concentration (up to 15% w/v) and the sugar stream produced using this technology is specifically suitable to be used for development of advanced biofuels such as yeast lipids.