Seaweeds are Potential Source for Production of Sustainable Bioethanol for the Imminent Future

The pursuit of Sustainable and renewable energy sources has gained immense importance in the face of Global energy and environmental challenges. The current fossil fuel reserves are not sufficient and very soon will become exhausted. Seaweeds, commonly known as marine algae, have emerged as a promising candidate for Bioethanol production due to their abundance, rapid growth, and minimal competition with food crops. Bioethanol has attracted attention as an alternative to petroleum-derived fuel; the production process involves the extraction of polysaccharides, primarily cellulose and alginate, from seaweed biomass. These polysaccharides are subjected to enzymatic hydrolysis and fermentation to convert them into bioethanol. Some seaweed species that have been studied and explored for bioethanol production includes Saccharina japonica (Kelp) which is known for its high cellulose content, making it a valuable source of biomass for bioethanol production. Similarly, Gracilaria verrucosa, a red seaweed, can be utilized in bioethanol production. These approach not only mitigates the demand for traditional feedstock like corn or sugarcane but also reduces greenhouse gas emissions and land use conflicts. This review delves into the intricacies of bioethanol production tailored to these seaweed species, and their associated microorganisms involving enzymatic hydrolysis with cellulolytic and xylanolytic bacteria like Clostridium sp., Cellulomonas sp., Bacillus sp.; fungi such as Trichoderma sp., Fusarium sp.; and fermentation with Saccharomyces cerevisiae. Species-specific optimizations are critical to ensure efficient and high-yield bioethanol production. Challenges such as seasonal variability, logistical issues, and the need for large-scale seaweed cultivation infrastructure are also explored, along with potential solutions. Overall, this chapter emphasizes the production of bioethanol from multiple seaweed species presenting a sustainable and eco-friendly alternative in the quest for renewable energy sources, offering the potential to reduce our reliance on fossil fuels and mitigate the impacts of climate change.