Effect of KOH Pretreatment on Lignocellulosic Waste to be Used as Substrate for Ethanol Production

In present study, Leptochloa fusca (Kallar grass) and Gossypium herbarium (cotton stalk) were treated with various concentrations of KOH (1, 1.5, 2, 2.5 and 3%) for different soaking periods (6, 12, 24 and 48 h) to expose maximum cellulosic content. The results showed that maximum cellulose exposure and delignification was increased with the increase in concentration of alkali and soaking time. However, maximum cellulose content (Kallar grass 49.01 +/- 0.1%, cotton stalk 56.12 +/- 0.1%) was achieved with 2.5% KOH at 24 h and a decline was observed as further increase in concentration of KOH (3%). Moreover, maximum delignification (Kallar grass 66.2%, 62.6 cotton stalk) was observed at 3% KOH after 48 h of soaking period. However, these results showed adverse effect of higher concentration of alkali on holocellulose. The cellulosic content of Kallar grass and cotton stalk after pretreatment at suitable conditions indicated that these substrates could be used as promising substrates for saccharification process to the produced second generation biofuel.