Synergistic effect of peroxidase and nonionic surfactant to improve enzymatic hydrolysis of corn stover

Lignocellulosic biomass is a sustainable and inexpensive alternative to petroleum based fossil fuel to produce energy. However, commercialization of biomass to ethanol technology remains challenging due to the low cellulose/hemicellulose conversion efficiency. To improve hydrolysis yield, peroxidase from Coprinus cinereus (CiP), non-ionic surfactants, and the combination of both were evaluated for their ability to improve hydrolysis of dilute acid pretreated corn stover (PCS) in both fully washed and unwashed forms. The study indicates that CiP increased sugar yield from unwashed PCS. Since most of the phenolic compounds were removed during washing process, the effect of peroxidase on hydrolysis of washed PCS was insignificant. Non-ionic surfactants can enhance hydrolysis of both washed and unwashed PCS. The positive effect was more pronounced on the washed PCS hydrolysis than on unwashed PCS, possibly due to the presence of soluble compounds including salts and phenolics in the pretreatment liquor. CiP peroxidase and non-ionic surfactants showed synergistic effect in unwashed PCS hydrolysis. The most significant improvement of glucose yield (10-14 g/L) from this unwashed PCS hydrolysis (20% total solid, 4 mg enzyme/g cellulose) was observed when 0.12 mg CiP/g cellulose and 0.02 g Levapon/g dry solid were added. Based on these findings, the development of a more efficient hydrolysis process is more attainable since the high operational costs associated with substrate washing and high enzyme consumption can be avoided.