Metal recovery using nanobiotechnology

Abstract Nowadays, nanoscale matter has started a revolution in manufacturing and industrialization processes like metal recovery. However, the chemical synthesis of nanoparticles has several disadvantages such as high initial capital cost, hazardous environmental effects, and slow metal recovery. To overcome these situations, the green synthesis of nanoparticles has gained attention due to its cost-effectiveness and ecofriendly nature. In the present era, nanobiotechnology is a major approach to recover several valuable metals. Different organisms like plants, fungi, algae, and bacteria have the ability to synthesize nanoparticles. Polyphenolic compounds from plant extracts have great antioxidant and reducing properties that can enable the reduction of metal ions into zero-valent metal atoms. NADH-dependent nitrate reductase enzymes act as a stabilizer in the formation of nanoparticles. Microbes like Pseudomonas, Bacillus, Shewanella, Geobacter, Klebsiella, and Desulfovibrio are capable of synthesizing nanoparticles and recover valuable metals like platinum, palladium, gold, silver, selenium, uranium, and copper.