Co-fermentation of immobilized yeasts boosted bioethanol production from pretreated cotton stalk lignocellulosic biomass: Long-term investigation

•Applied pretreatments were effective in lignin depolymerization of cotton stalk (CS).•SEM, FTIR, TGA, and XRD presented that both pretreatments disintegrated CS.•Immobilized yeast sustained potential bioethanol production till 2nd cycle of 96 h.•Bioethanol production declined at 3rd cycle and reached to the lowest value at 5th.cycle.