A critical review on the development stages of biorefinery systems for sugarcane processing wastes

Sugarcane processing is a globally significant industrial endeavour that generates an astoundingly large quantity of lignocellulosic waste. Annually, approximately 1.8 billion tons of bagasse alone is produced, representing a substantial by-product of the sugarcane industry. However, current disposal practices, such as landfilling without proper methane capture systems or incineration using outdated technologies, exacerbate the environmental burden. Landfills release methane, a greenhouse gas with over 25 times the global warming potential of carbon dioxide over a 100 - year period, whereas sub-standard incineration emits harmful pollutants such as particulate matter and sulfur dioxide. An in-depth review is presented, examining diverse biorefinery pathways for the conversion of these wastes. Bagasse conversion into bioenergy, such as ethanol via enzymatic hydrolysis and fermentation of cellulose and hemicellulose, and biogas via anaerobic digestion, is a promising approach. Biochemical production from sugarcane waste feedstocks, such as citric acid via microbial fermentation and polylactic acid (PLA), presents considerable potential. Benchmarking apple pomace valorization reveals sugarcane waste's unique utilization potential. Three systemic barriers persist: poor integration (resource inefficiency), economic fragility (feedstock price volatility and high costs), and inadequate life-cycle assessments. AI-driven modular platforms for optimization, dynamic techno-economic models, and region-specific sustainability metrics. These findings position sugarcane waste as a cornerstone of the circular bioeconomy, particularly in sugarcane-growing nations of the Global South.