Biofuels have environmental friendliness, attracting interest from all over the world. As a carbon-neutral energy source that is renewable, unlike fossil fuels, which would cause global warming, biofuels do not upset the balance of air molecules in the atmosphere. Reducing reliance on traditional fossil fuels by employing biofuels is among the most feasible approaches. The world's most abundant biomass, lignocellulose, may be found in practically all extant plants as leaves, peels, bodies, branches, etc. As fossil fuels are used up, there is a growing need for renewable energy, particularly biofuels (Palmqvist et al., 2000). Therefore, the manufacturing of lignocellulosic bioethanol is unquestionably a method of supplying energy, particularly for nations.

Agriculture and agro-industrial wastes, as well as inexpensive lignocellulosic biomass supplies. These materials can range from sawdust to poplar trees, sugarcane bagasse to brewer's leftovers, grasses and straws to grain stems, leaves, husks, shells, and peels from corn, sorghum, and barley. Despite using these materials to create valuable products, lignocellulose wastes continue to accumulate annually in enormous amounts, posing environmental issues (Sheehan, 2001). The polysaccharides in lignocellulose wastes are inherently shielded by their structure from enzyme and chemical hydrolysis, making the chemical and biological conversion of lignocellulose to other products, including ethanol, more challenging. Lignins are involved in the cross-linking of cellulose and hemicellulose in the matrix. These characteristics of lignins increase the strength and hardness of the lignocellulose structure. Pretreatment, which removes lignins from lignocellulose and improves the penetration of hydrolysis agents, is therefore an essential stage in the process of turning biomass into bioethanol (Sheehan, 2001). Before lignocellulose is hydrolyzed and fermented, pretreatment procedures are done. Before-hand care To make cellulose more easily hydrolyzed, more amorphous areas should be present. To pretreat lignocelluloses, many physical, chemical, and biological techniques are applied. use of chemicals It is well known that lignin can be dissolved in aqueous, acidic and alkaline solutions. In order to potentially co-ferment hemicellulose with a tailored yeast strain and produce the highest bioethanol output in history—up to 29% (%) dry matter—the ideal K3PO4 pretreatments could leave nearly all of the xylose in the hemicellulose (Fu, et al., 2022). For the most efficient and practical lignocellulosic bioethanol production method, acidic and alkaline pretreatments of lignocellulose are used (Szczodrak et al., 1986, Farid et al., 1983). Acidic pretreatments: sulfuric acid and hydraulic acid are frequently used, although they are not particularly advised due to the production of furfural compounds during the pretreatment process, which prevents the growth of microorganisms during the fermentation process (Zhang et al., 2016, Zhang et al., 2023). The loss of carbohydrates from hydrolysis is reduced when lignocellulose is first treated with an alkaline solution. Additionally, it facilitates a later hydrolysis, inhibits the production of furfural, and helps to eliminate acetyl groups. Because of its affordability and excellent efficacy, NaOH is the most often used alkali for lignin removal in lignocelluloses (Rolz et al., 1986, Nazarpour, 2013). The single pretreatment technique doesn't seem to be able to produce the desired outcome. It has long been practiced to combine several pretreatment techniques. The polysaccharide-enriched material is hydrolyzed to hexoses by enzymes after lignocellulose has undergone pretreatment (Chen et al., 2017, Fernandes et al., 2015). Cellulases, a general term for a variety of enzymes that are isolated from microorganisms, are what are used in commercially available products to hydrolyze cellulose. These enzymes cleave glycosidic bonds in carbohydrates, often via inverting or retaining processes, the latter of which advances. Microorganism development during fermentation is facilitated by enzymatic hydrolysis. The single sugars that were released as a result of enzymatic hydrolysis are metabolized by fermentation microorganisms to produce bioethanol. The enhanced cellulose nanofibrils demonstrate efficacy in stimulating the release of lignocellulose-degradation enzymes from fungi, as seen by the 100% and 138% increase in the activity of the two cellulases (exoglucanases and β-glucosidases), as well as the 44% rise in total protein content. Our findings thus point to a unique environmentally friendly method of combining precise genetic alteration of lignocellulose substrates with effective biomass process technology to achieve high-quality diversified bioproduction (Zhang et al., 2023).

The aim of the work is to produce bioethanol as renewable energy by using different agricultural wastes (dry leaves, green leaves, tops of sugarcane, shell, and deoiled seed cake of jatropha). The main biopolymers (cellulose, hemicellulose, and lignin) were extracted by using different alkaline solutions (sodium hydroxide and hydrogen peroxide). SEM, EDXA and FTIR were used to compare the effects of the two methods. The results showed that the pretreatment with H2O2 was more efficient than NaOH. The application of extracted methods was a new trend that improved the biomass of bioethanol production by decreasing the inhibitors of fermentation processes.