Ribosomal Genes‐Based Identification, Bioprospecting of Algae, and the Impact of Nanomaterials on Their Cell Integrity

Microalgae are emerging as a valuable resource of bioenergy, value-added products, and contribute significantly to carbon sequestration. However, the diversity of endogenous algae in countries like India and their bioprospecting potential is not yet fully explored. During this study, microalgae from the freshwater of Aligarh, India, were isolated, identified using 18S rRNA, ITS and 16S rRNA gene sequences, and screened using GC-MS analysis for their potential use as biofuel. Two isolated strains were identified as members of the genus Chlorella based on ribosomal gene sequences, cell, and colony morphologies. When detected using GC-MS analysis, the strain was found to produce significant quantities of phytol, pentadecanone, and other compounds typically found in algal oil. The influence of silver nanoparticles (~32 nm) and TiO₂ nanoparticles (~23 nm) on the cell integrity of algae was checked using direct microscopy and CSLM analysis after staining with propidium iodide and Syto9. It was found that with 50, 100, and 200 µg/mL of Ag-NPs, the population of intact cells decreased by 20%, 51%, and 79%, as seen under a light microscope, while TiO₂-NPs were less toxic to the cells, decreasing population only by 0%, 12%, and 35%, respectively. When checked using Scanning Laser Microscope after growing with 100 and 200 µg/mL of Ag-NPs and TiO₂-NPs, the population of dead cells increased to 59% and 93%, and 16% and 46%, respectively. These results show that the isolated strains can serve as a source of bioenergy, and nanomaterials can promote cell lysis for downstream processes.