Phytotoxicity and Effect of Water Saturated Fractions of Hexane on Growth of Microalgae

Denise, E. M.^*, Akpan, E. N. & Anyadike, M. C.

Department of Botany and Ecological Studies, University of Uyo, Uyo, AkwaIbom State, Nigeria

Dr. Denise, E. M., Department of Botany and Ecological Studies, University of Uyo, Uyo, AkwaIbom State, Nigeria.

Keywords: Phytotoxicity; Water Saturated Fractions; Hydrocarbons Bioremediation Potential; Growth and Microalgae

Abstract

Phytotoxicity and the effects of water saturated fractions of Hexane on growth of microalgae was carried out using three species of fresh water microalgae namely Chlorella vulgaris (Chlorophyte), Nitzschia palea (Diatom) and Anabaena flosaquae (Cyanobacterium). The microalgae were grown separately in ratios 1:9 of 0%, 10%, 25%, 50%, 75% and 100% of water saturated fractions of Hexane. Algal growth was estimated using spectrophotometer using an absorbance of 745nm. Phytotoxicity was measured using percentage inhibition. C. vulgaris showed growth stimulation at 10% - 50% concentrations of the WSF while 75% and 100% concentrations were inhibitory. A. flosaquae showed growth stimulation in 10% - 75% of the WSF. N. palea showed growth stimulation at all concentrations (10% - 100%) of the WSF of the hydrocarbons. The inhibitory effects observed in this study at higher concentrations were more pronounced during the exponential growth phase. The order of order of growth stimulation or response of microalgae is N. palea> A. flosaquae> C. vulgaris. The results obtained showed mineralization pattern of the hydrocarbons by the different species of microalgae and thus could be an addition to existing list of indicators microalgae of crude oil hydrocarbon polluted environment and microorganism with hydrocarbon bioremediation potentials. This results obtained from this study could be an addition to existing data on the subject and hence useful in environmental management.

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