Optimizing the Removal of Microbial Inhibitors From Steam Exploded Lignocellulosic Biomass to Improve Hydrogen Production
Abstract
Biohydrogen (bio-H2) is a possible future alternative energy source. Hydrogen (H2) derived from cheap agriculture feedstocks is a necessary requirement for economical full-scale production. Solubilizing cellulose, hemicellulose and other organic components in low value feedstocks is accomplished by processes such as acid treatment or steam explosion. During pretreatment, microbial inhibitors such as furfural and hydroxymethyl furfural (HMF) are generated from hexose and pentose sugars. A commercially available ion-exchange resin (XAD-4) was used to remove furan inhibitors from liquor derived from pretreating low value agriculture residues. A surface response model was used to predict inhibitor concentrations after 360 minutes of treatment. Experiments were conducted to demonstrate the impact of treating switchgrass liquor with XAD-4 resin on the H2 yield. Treated and untreated switchgrass liquor generated maximum yields of 2.25 ± 0.14 and 1.80 ± 0.11 mol H2/mol glucose, respectively. In comparison, a yield of 2.14 ± 0.21 mol H2/mol glucose was detected in cultures fed pure glucose.