Isolation, culture trials, and biochemical composition of microalga Tetraselmis from coastal waters of Tanzania

Abstract

Microalgae are primary producers in aquatic ecosystems. Their high nutritional value make them suitable for applications in aquaculture and biotechnology. Serial dilution techniques were used to isolate the green microalga Tetraselmis sp. from water samples collected from the Ruvu Estuary in Tanzania. Laboratory culture trials were undertaken at varying salinity and light intensity levels, followed by biochemical analysis. Intermediate salinities (15 and 35) favoured cell accumulation, and light intensity significantly influenced Tetraselmis biochemical composition. Low light intensity (2.9 ± 1.6 Klux) and early harvests (day 7) increased the protein, lipid, carbohydrate and fibre content, whereas high light intensity (5.5 ± 3.3 Klux) led to greater ash accumulation. The day 16 harvest contained higher levels of minerals, with calcium, potassium, and magnesium being prominent. Trace minerals, including selenium, were present in safe quantities. The potential of Tetraselmis sp. from coastal Tanzania for aquaculture and biotechnological applications is highlighted.