Feedstocks Improvement

Biomass components mainly include lignocellulose, extractives, lipids, pro­teins, simple sugars, starches, H2O, hydrocarbons, ash, and other compounds (Kumar et al. 2009). Lignocellulosic biomass chemically consists of three main fractions: (1) cellulose (CH1.67Oo.83), (2) hemicellulose (CH1.64Oo.78), and (3) lignin (C1oH11O35). Cellulose is a polymer of glucose (a C6 sugar), which can be used to produce glucose monomers for fermentation to, for example, bioethanol. Hemicellulose is a copolymer of different C5 and C6 sugars including, for exam­ple, xylose, mannose, and glucose, depending on the type of biomass. Lignin is a branched polymer of aromatic compounds. The cellulose present in lignocellulosic biomass is resistant to hydrolysis. Therefore, to produce bioethanol or biobutanol from lignocellulosic biomass via biochemical route, it is essential that the biomass is pretreated in order to enable hydrolysis of the cellulose into sugars. Different pretreatment technologies have been developed (steam explosion, treatment with acids or bases, etc.) (Table 3), but the common purpose of these technologies is to break open the lignocellulosic structure. The primary goal of feedstock improve­ment should be to enhance the quality and efficiency of the pretreatment process, which would necessarily involve pretreatment efficiency and enzyme efficacy.