The siliceous exoskeletal shells of diatoms, commonly known as frustules, have drawn attention because of their photoluminescence property and high volume to surface area. Photonic biosilica can also enhance the plasmonic sensitivity of nanoparticles. Because of this, researchers have studied the effectiveness of various metal particles after combining with biosilica. Additionally, naturally occurring diatom-based biosilica has excellent adsorption and absorption capabilities, which have already been exploited for wastewater treatment. Moreover, the nanoporous, ultra-hydrophilic frustules can easily accumulate more molecules on their surfaces. As a consequence, it becomes easier to conjugate noble metals with silica, making them more stable and effective. The main focus of this review is to agglomerate the utility of biocompatible diatom frustules, which is a no-cost natural resource of biosilica, in metal modification and removal.

The diatom genus, Halamphora subturgida, was exposed to various nitrate salt concentrations (882 µM, 441 μM and 1,764 μM) for a period of 18 days. The Chlorophyll content of diatom biomass (14.95 ± 0.04 µg/ml) reflected better growth, subjected to 1,764 µM NO⁻³ for a period of 12 days as compared to control (882 µM NO⁻³) and nitrogen depleted (441 µM NO⁻³) conditions. Fucoxanthin estimation showed a similar trend as chlorophyll content and reached its peak at nitrogen‐repleted (1,764 µM NO⁻³) condition (25.70 ± 0.03 µg/ml). The total carotenoid (26.92 ± 0.05 µg/ml) and protein content (87.49 ± 0.06 mg/g) were found to be maximal after 12 days of incubation in nitrate sated medium. Thus, the diatom exposed to 12 days' nitrate sated medium (1,764 µM NO⁻³) was selected as fish feed ingredients to gold fish (Carassius auratus). Total Algal Feed (TAF) was prepared from mixed algal biomass of Halamphora subturgida, Spirulina and Leptolyngbia. The commercial feed (CF) was replaced by varying proportions of algal mix to formulate three different types of Value Added Feed (VAF‐25%, 50%, 75% VAF). The feed type formulated as 75% VAF was found to be most effective in terms of skin pigmentation, growth and antioxidant activities of experimental fish showing almost 1.44‐ to 4‐ fold increase, compared with the control fish. Body weight gain and specific growth rate also changed significantly in experimental fish.

SCIEPublish is an international open-access journal publishing service provider run by SCIE Publishing Limited, dedicated to supporting and inspiring scientists or institutions/societies who aspire to publish high-quality journals.