abstract
In this study, production of cellulosic ethanol from two cotton processing residues was investigated after
pretreatment with dilute sodium hydroxide. Pretreatment performance was investigated using a 22 factorial
design and the highest glucan conversion was achieved at the most severe alkaline conditions (0.4 g
NaOH g1 of dry biomass and 120 C), reaching 51.6% and 38.8% for cotton gin waste (CGW) and cotton
gin dust (CGD), respectively. The susceptibility of pretreated substrates to enzymatic hydrolysis was also
investigated and the best condition was achieved at the lowest total solids (5 wt%) and the highest
enzyme loading (85 mg of Cellic CTec2 g1 of dry substrate). However, the highest concentration of fermentable
sugars – 47.8 and 42.5 g L1 for CGD and CGW, respectively – was obtained at 15 wt% total
solids using this same enzyme loading. Substrate hydrolysates had no inhibitory effects on the fermenting
microorganism.