In an attempt to mimic white-rot fungi lignin degradation via in vivo Fenton chemistry, solution phase Fenton chemistry (10 g biomass, 176 mmol hydrogen peroxide and 1.25 mmol Fe(2+) in 200 mL of water) was applied to four different biomass feedstocks. An enzymatic saccharification of Fenton pretreated biomass showed an average 212% increase relative to untreated control across all four feedstocks (P<0.05, statistically significant). A microbial fermentation of the same Fenton pretreated biomass showed a threefold increase in gas production upon a sequential co-culture with Clostridium thermocellum and Clostridium beijerinckii. These results demonstrate the use of solution phase Fenton chemistry as a viable pretreatment method to make cellulose more bioavailable for microbial biofuel conversion.