Phycoremediation of As(III) and Cr(VI) by Desmodesmus subspicatus: Impact on growth and biomolecules (carbohydrate, protein, chlorophyll and lipid) – A dual mode investigation

Abstract

Microalgae are under research focus for the simultaneous production of biomolecules (e.g., biofuels) and bioremediation of toxic materials from wastewater. The current study explores the capability of indigenously isolated microalgae (Desmodesmus subspicatus) for phycoremediation As(III) and Cr(VI) along with the production of biomolecules by alternating its extracellular and intracellular compositions. Desmodesmus subspicatus survived up to the toxicity level of 10 mg/L for As(III) and 0.8 mg//L for Cr(VI). A decline in carbohydrate accumulation (⁓70%) at 10 mg/L of As(III) concentration was obtained. An increased content of protein (⁓28%) and lipid (by ⁓32%) within the cells of Desmodesmus subspicatus was observed when grown in 0.5 and 0.2 mg/L As(III) concentrations respectively. A descending trend in carbohydrate accumulation was noted with increasing Cr(VI) concentration and the least (~44%) was recorded at 0.8 mg/L Cr(VI). Desmodesmus subspicatus showed an excellent maximum removal efficiency for Cr(VI) and As(III) as 77% and 90% respectively.