Ethanol production via in situ fungal saccharification and fermentation of mild alkali and steam pretreated corn fiber

The effect of mild alkali and steam pretreatments on fungal saccharification and sequential simultaneous-saccharification and fermentation (SSF) of corn fiber to ethanol was studied. The corn fiber was pretreated with: (i) 2% NaOH (w/w) at 30 °C for 2 h and (ii) steaming at 100 °C for 2 h. Ethanol yields were 2.6 g, 2.9 g and 5.5 g ethanol/100 g of corn fiber, respectively, for Phanerochaete chrysosporium, Gloeophyllum trabeum and Trichoderma reesei saccharification and sequential SSFs. SSF with commercial cellulase enzyme – Spezyme-CP had 7.7 g ethanol/100 g corn fiber. Mild alkali pretreatment resulted in higher glucose yields following fungal saccharification of corn fiber. However, the ethanol yields were comparatively similar for untreated and mild alkali pretreated corn fiber. Solid-substrate fermentation of corn fiber with fungi can be improved to either eliminate or reduce the dosage of commercial cellulase enzymes during SSF.