Asian Journal of Biotechnology and Bioresource Technology

Microalgae are recognised as potential sources of diverse phytochemical compounds with biological and biotechnological significance. However, information on the molecular identity and phytochemical composition of Halochlorella rubescens from freshwater environments remains limited. This study addresses this gap by investigating the molecular identification and phytochemical profile of H. rubescens isolated from Kolavai Lake, India. The present study aimed to isolate, identify, and characterize the phytochemical constituents of Halochlorella rubescens collected from Kolavai Lake, India. The isolated microalga was cultivated in Bold’s Basal Medium (BBM), and its morphological characteristics were examined microscopically. Molecular identification and phylogenetic analysis were performed using the Maximum Likelihood method based on the Tamura–Nei model in MEGA 12. The ethanolic extract of H. rubescens was subjected to qualitative and quantitative phytochemical analyses. Qualitative screening revealed the presence of tannins, phenols, cardiac glycosides, steroids, terpenoids, and quinones, while alkaloids, flavonoids, saponins, and proteins were not detected in the preliminary screening. Quantitative analysis revealed a total phenolic content of 15.61 mg gallic acid equivalents (GAE)/g and a flavonoid content of 5.22 mg quercetin equivalents (QE)/g of dried extract. These findings demonstrate the presence of diverse phytochemical constituents in H. rubescens. Further studies on its antioxidant, antimicrobial, and other biological activities are warranted to evaluate its potential applications in pharmaceutical, nutraceutical, and biotechnological fields.