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Biokinetics of arsenate accumulation and release in Microcystis aeruginosa regulated by common environmental factors: Practical implications for enhanced bioremediation

Wang, Zhenhong, Luo, Zhuanxi, Yan, Changzhou, Rosenfeldt, Ricki R., Seitz, Frank, Gui, Herong
Journal of cleaner production 2018 v.199 pp. 112-120
Microcystis aeruginosa, adsorption, algae, arsenates, arsenic, bioaccumulation factor, bioremediation, environmental factors, nitrates, orthophosphates, pH, partition coefficients, specific growth rate
Only little information is available on combined effects of abiotic environmental factors on algal arsenate (AsV) metabolic biokinetics. Using the Taguchi statistical method, we investigated four environmental factors including AsV, nitrate (N), orthophosphate (P) and pH for their combined effects on algal growth and arsenic (As) uptake but also extracellular adsorption of Microcystis aeruginosa, as well as As release from dead algal cells. Results showed that an increase of N facilitated M. aeruginosa growth and thus was the principal factor for the algal maximum specific growth rate (μmax). P was vital to AsV bioconcentration factor (BCF) and As partition coefficients (LogKd) released from deal algal cells. AsV impacted the extracellular As adsorption onto the algal cells, which thereby increased with increasing initial AsV level. The initial pH had an imperative effect on the AsV uptake (ku) and release rate (Ke) from the dead cells. The optimum conditions on AsV metabolic biokinetics were N at 10.0 mg L−1 for μmax, P at 0.02 mg L−1 for LogKd and BCF, AsV at 10.0 μM for extracellular As adsorption, and pH at 10 for ku, BCF and extracellular As adsorption, but pH at 6 for Ke. Collectively, the condition of low P, high N and alkaline pH level was favorable to As accumulation rate of living cells and restrictive to As release rate from dead cells of M. aeruginosa. The obtained information can pave a road for extensive understanding on efficient utilization of As bioremediation of algae in practical environment.