Nanoparticle applications in Algal-biorefinery for biofuel production

Rapidly depleting fossil fuel resources and rising greenhouse gas emissions have accelerated the search for cost-effective renewable energy sources. Algal feedstock has long been touted as a potential source of several biofuels because of its renewable and sustainable features. However, despite ongoing efforts to develop low-cost technology and improve economic feasibility, biofuels derived from algae are still not yet commercially viable. Multifunctional nanoparticles (NPs) have been proposed as a strategy to enhance the prospect of commercializing algal-based biofuels. NPs synthesized by various routes can support different stages of algal biorefinery. Improvement of 20–30 % cell growth, 80–99 % harvesting efficiency, enhanced product extraction, and ∼85–99 % conversion were achievable with NPs addition. This review provides a comprehensive outlook on the current and significant applications of NPs in the production of different algal-based biofuels such as biodiesel, bioethanol, biohydrogen, biogas, bioelectricity, and jet biofuel as well as in the implementation of algal biorefinery. The challenges, future trends, and the roadmap for further improvements in NP-assisted algal biofuels are also highlighted. Overall, this comprehensive review will help in understanding the recent advanced applications of nanoparticles in the production of algal biofuels.