Process and technoeconomic analysis of bioethanol production from residual biomass of marine macroalgae Ulva lactuca

A mild and efficient pretreatment strategy for the high-value utilization of cellulose derived from Sargassum spp

Algae are pivotal in biofuel production, with pretreatment serving as a crucial step in the process. Traditional methods predominantly rely on strong acids, bases, or high temperatures, which contradict the principles of green and sustainable development. To overcome these challenges, this study optimized a novel chemical pretreatment method for Sargassum spp. using ultrasound-assisted KMnO₄ and Na₂SO₃ at 20-60 °C. Key parameters, including reagent concentration, temperature, and reaction time, were refined, with optimal conditions established at 40 °C for 4 h. Ultrasound improved reagent permeability, while KMnO₄ and Na₂SO₃ disrupted the biomass structure through redox reactions. The cellulose content in the residual biomass increased from 11.99 wt% to 23.88 wt%, while AIR content decreased to 15.96 wt%. The maximum cellulose enzyme accessibility reached 19.56 mg/g. Compared to conventional methods, the glucose yield from Sargassum spp. hydrolysis increased from 51.62 mg/g to 107.75 mg/g, and ethanol yield from fermentation rose from 24.61 mg/g to 50.90 mg/g. This study presents a simple, cost-effective, efficient, and environmentally friendly pretreatment method for algal biomass, highlighting its significant industrial potential.

Use of Residual Lignocellulosic Biomass and Algal Biomass to Produce Biofuels

Efforts are intensifying to identify new biofuel sources in response to the pressing need to mitigate environmental pollutants, such as greenhouse gases, which are key contributors to global warming and various worldwide calamities. Algae and microalgae present themselves as excellent alternatives for solid-gaseous fuel production, given their renewable nature and non-polluting characteristics. However, making biomass production from these organisms economically feasible remains a challenge. This article collates various studies on the use of lignocellulosic waste, transforming it from environmental waste to valuable organic supplements for algae and microalgae cultivation. The focus is on enhancing biomass production and the metabolites derived from these biomasses.

Comprehensive assessment of biorefinery potential for biofuels production from macroalgal biomass: Towards a sustainable circular bioeconomy and greener future

Marine macroalgae have attracted significant interest as a viable resource for biofuel and value-added chemical production due to their abundant availability, low production costs, and high carbohydrate and lipid content. The growing awareness of socio-economic factors worldwide has led to a greater consideration of marine macroalgae as a sustainable source for biofuel production and the generation of valuable products. The integration of biorefinery techniques into biofuel production processes holds immense potential for fostering the development of a circular bioeconomy on a broad scale. Extensive research was focused on the technoeconomic and environmental impact analysis of biofuel production from macroalgal biomass. The integrated biorefinery processes offers valuable pathways for the practical implementation of macroalgae in diverse conversion technologies. These studies provided crucial insights into the large-scale industrial production of biofuels and associated by-products. This review explores the utilization of marine macroalgal biomass for the production of biofuels and biochemicals. It examines the application of assessment tools for evaluating the sustainability of biorefinery processes, including process integration and optimization, life cycle assessment, techno-economic analysis, socio-economic analysis, and multi-criteria decision analysis. The review also discusses the limitations, bottlenecks, challenges, and future perspectives associated with utilizing macroalgal biomass for the production of biofuels and value-added chemicals.