AbstractProduction of bioethanol from lignocellulosic biomass is difficult due to differences in the feedstock. There is a need for an efficient pretreatment method that not only reduces the total process economy but also increases the total process efficiency. Following microwave-NaOH pretreatment of peanut shells in the presence of the cationic ionic surfactant cetyltrimethylammonium bromide (CTAB) and enzymatic hydrolysis, the pretreatment efficiency was significantly enhanced. The structural changes before and after pretreatment were detected by Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). FTIR and SEM showed the differences between the untreated and pretreated samples. The XRD profile showed that the degree of crystallinity was higher for pretreated materials than for untreated ones. These changes also verified the effect of CTAB during pretreatment of peanut shells.