Fungal Pretreatments for Lignocellulosic Bioconversion

Lignin and complex polysaccharides limit the efficiency of chemical and enzymatic conversion of lignocellulosic biomass into ethanol. Processing technologies that address these problems are needed to advance lignocellulosic biofuel production. In the current research, whole-organism wood decay fungi were utilized as a pretreatment process for improved lignocellulosic bioconversion. Corn stover, Miscanthus, switchgrass, kenaf, and tulip poplar were selectively decayed with white rot (Ceriporiopsis subvermispora) and/or brown rot (Postia placenta) fungal treatments. Both white-rot and brown-rot fungi were successfully grown alone or in succession on all biomass types tested. Significant lignin removal and minimal polysaccharide loss were observed in some treatments, resulting in biomass with significantly improved chemical and mechanical properties for downstream conversion into ethanol. Glucose analysis determined that select fungal pretreatments effectively depolymerized lignin and increased the efficiency of enzymatic polysaccharide hydrolysis. Fungal bioconversion treatments determined at the laboratory scale to be best-suited for lignocellulosic ethanol production were applied on site at the Catawba County, NC Regional EcoComplex in a small scale pilot study.