Antibacterial activity and biomolecular composition of certain fresh water micro-algae from River Godavari (India)

Abstract

Twenty four fresh water algal species were screened for their antibacterial activity and biomolecules. Bactericidal activity was tested against two gram +ve and four gram -ve bacteria. Maximum antibacterial activity was observed in methanol extracts and least in aqueous extracts. Maximum activity (14mm) was observed in the extracts of Nostoc, Lyngbya, Mougeotia and Pithophora sp. Gram +ve bacteria were more susceptible than gram -ve bacteria. Thirteen algal species are associated with tannins and phenols, 11 species with steroids, 5 species with flavonoids and 8 species with saponins. Maximum
chlorophyll-a was recorded with Ulothrix (5.6 mg/g) and least in Tolypothrix (0.5 mg/g). Chlorophyll-b was recorded maximum in Vaucheria (4.2 mg/g) and least in Cylindrospermum (0.6 mg/g). Maximum carotenoid content was recorded in Ulothrix (4.5 mg/g) and least in Tolypothrix and Oscillatoria (0.6 mg/g). Range of protein content was 4-20% with maximum yield in Cylindrospermum sp. (20%) and least in Hydrodictyon (4%). Carbohydrate content ranged from 14-35% with maximum yield in Mougeotia (35%) and least in Tolypothrix (14%). Their pharmacological activities and bioactive molecules can be highly exploited.

Key words: Fresh water Algae, antibacterial activity, phycochemicals, phycopigments