(418aq) Progress Toward Developing Nature-Inspired and Low-Cost Lignocelluloses Processing Technologies

Lowing pretreatment cost of lignocellulosic biomass for obtaining and biochemical conversion of cellulosic sugars requires that plant cell deconstruction occurs under conditions with less severity than that of the currently practiced technologies.  Eliminating heat and pressure requirements will allow reactors to be constructed with inexpensive metals.  The authors’ laboratory has been studying plant cell wall degradation in model natural systems such as that of termite and white-rot fungi.  The emerging new knowledge suggests that although termite and fungi have different plant cell deconstruction systems with drastically different efficiencies there are some similarities in their mechanisms for lignin modification.  It is believe that radical generation from Fenton type of reactions is the key that turns on the reaction process.  Building on these results, different chemical reaction systems have been developed to mimic these reactions using chemical based catalysts.  Various degrees of success have been obtained.  When ozone was used to modify the lignin structure followed by ammonia soaking to remove the lignin, biomass sacchatification efficiency of 90% was achieved.  When hydrogen peroxide was used as the main reaction species for generating radical based reactions, the efficiency was greatly affected by the pH and types of chelators as well as metals employed.  The results demonstrate that treatment processes that operate under ambient conditions are possible.  Tradeoffs needs to be made between process rate and capital cost.