Microalgae as sustainable bio-factories for nanoparticle biosynthesis: Progress and challenges

Abstract

Conventional methods of nanoparticle production suffer from various limitations, including the toxicity of precursor materials, the imperative for stringent temperature regulation, and exorbitant synthesis costs, thereby limiting their applicability. Therefore, the green synthesis of nanoparticles has emerged as a clean, non-toxic, and eco-friendly technique, which offers great potential due to both environmental and economic prospects. This review comprehensively explores the green synthesis of metallic nanoparticles, with focus on microalgae-mediated processes, and provides comparative insights of biogenic synthesis contrasted to traditional synthesis while critically discussing the major unresolved issues in using microalgae for nanoparticle synthesis. Furthermore, this work critically examines the factors influencing nanoparticle synthesis, and addresses the challenges and strategies pertaining to stability, separation, yield, agglomeration, morphology, crystal growth, and toxicity. This work also explores new opportunities and directions to improve toxicity mitigation strategies and enhance the biosynthesis efficiency through genetic engineering and metabolic pathway.