Recent advances in bioethanol production from rice straw and husks by physical, chemical, and biological pretreatment methods

Agricultural waste is a major global concern, with the potential to be a value-added material given its composition. Due to the high lignocellulosic content in various types of agro-waste, there has been a drastic increase in demand for bioethanol production. In this review, the investigators comprehensively emphasized the role of various pretreatment techniques in increasing bioethanol production from lignocellulosic biomass (LCB), particularly rice straw (RS). Here, investigators reviewed lignin removal, hemicellulose solubilization, sugar release, and ethanol generation reported in previously published experimental studies. A comparative study of all the available pretreatment approaches for the rice straw was emphasized. Further, the most effective and sustainable pretreatment strategies were identified, and their implications were focused on for scalable bioethanol production. The integrated pretreatment strategies were found to be more effective, sustainable, and scalable for the production of second-generation bioethanol. These methods closely align with the United Nations Sustainable Development Goals (SDGs), particularly SDGs 7, 12, and 13, which promote the generation of renewable biofuels from agricultural residues.