Developing value added co-products from unhydrolyzed residue within the biochemical platform

A side product of enzymatic hydrolysis and fermentation of agricultural biomass is the remaining solids, composed of lignin, unhydrolyzed polysaccharides, protein, ash, and potentially microbial or fungal biomass.  The conventional paradigm for the biochemical platform is to combust this unhydrolyzed residue on-site for heat and power generation.  However, this approach is capital-intensive, accounting for nearly 30% of the total capital cost.  Biomass combustion also involves other problems such as fly ash disposal, regulations involving electricity generation, fouling, and competition with low-cost natural gas.  Removing co-generation as well as enabling off-site enzyme production and off-site pretreatment (such as AFEX^TM) would reduce the capital cost for a biorefinery by 65%.  Likewise, such an approach would also allow for relatively low cost retrofits of corn dry mill facilities, potentially allowing for rapid deployment of cellulosic ethanol production within the United States.

Thus, MBI is committed to finding alternate markets for this unhydrolyzed residue.  We examine the techno-economic impact of this approach and determine the potential selling price of unhydrolyzed residue.  We also examine the potential regulatory issues with this approach with respect to the Energy Independence and Security Act.  Multiple applications are investigated, including low-value applications such as soil amendments, a binder for wood pellets, and producing pellets for cooking stoves in developing nations, as well as higher value applications that MBI is currently developing and de-risking.  The potential market size as well as economic, environmental, and social impacts of each application will be discussed.