Phycoremediation Potential of Botryococcus braunii: Bioremediation and Toxicity of As(III) and As(V)

Worldwide threats of climate change because of greenhouse gas emissions and fuel shortages in near future are posing considerate challenges and therefore it is vital for exploring viable ways of preventing the consequences. The dual usage of microalgae for phycoremediation and biomass production for ecological biofuels production is a practicable choice. Accumulation and toxicity of inorganic arsenic forms (As(III) and As(V)) to the green microalgae Botryococcus braunii depends on various environmental factors. This study examined the possibility of using living algae B. braunii for phycoremediation of arsenic-enriched media (As(III) and As(V)). As(V) was more harmful than As(III), particularly at pH 7.0, but it was reverse at pH 9.0. The phycoremediation efficiency of As(V) at pH 9.0 by algal cells was higher than that As(III). An increase in concentration of phosphate in growth medium reduced the toxicity and phycoremediation of As(III) and As(V). Value of μ max remained almost constant after addition of arsenic (either As(III) or As(V)) in the media containing various concentration of phosphate ions, but the value of K s increased. The microalgae B. braunii can be employed for tertiary treatment of wastewater and the producing biomass can be utilized as source of renewable energy.