Sustainable Iron Recovery and Biodiesel Yield by Acid-Adapted Microalgae, Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, Grown in Synthetic Acid Mine Drainage

Sudharsanam Abinandan; Suresh R Subashchandrabose; Kadiyala Venkateswarlu; Mallavarapu Megharaj

doi:10.1021/acsomega.0c00255

Sustainable Iron Recovery and Biodiesel Yield by Acid-Adapted Microalgae, Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, Grown in Synthetic Acid Mine Drainage

ACS Omega. 2020 Mar 19;5(12):6888-6894. doi: 10.1021/acsomega.0c00255. eCollection 2020 Mar 31.

Authors

Sudharsanam Abinandan¹, Suresh R Subashchandrabose^{1

2}, Kadiyala Venkateswarlu³, Mallavarapu Megharaj^{1

2}

Affiliations

¹ Global Centre for Environmental Remediation (GCER), Faculty of Science, University of Newcastle, ATC Building, Callaghan, New South Wales 2308, Australia.
² Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), University of Newcastle, ATC Building, Callaghan, New South Wales 2308, Australia.
³ Formerly Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu 515003, India.

Abstract

Sustainable resource recovery is the key to manage the overburden of various waste entities of mining practices. The present study demonstrates for the first time a novel approach for iron recovery and biodiesel yield from two acid-adapted microalgae, Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, grown in synthetic acid mine drainage (SAMD). Virtually, there was no difference in the growth of the strain MAS3 both in Bold's basal medium (control) and SAMD. Using the IC₅₀ level (200 mg L^-1) and a lower concentration (50 mg L^-1) of iron in SAMD, the cell granularity, exopolysaccharide (EPS) secretion, iron recovery, and biodiesel were assessed in both the strains. Both cell granularity and accumulation of EPS were significantly altered under metal stress in SAMD, resulting in an increase in total accumulation of iron. Growth of the microalgal strains in SAMD yielded 12-20% biodiesel, with no traces of heavy metals, from the biomass. The entire amount of iron, accumulated intracellularly, was recovered in the residual biomass. Our results on the ability of the acid-adapted microalgal strains in iron recovery and yield of biodiesel when grown in SAMD indicate that they could be the potential candidates for use in bioremediation of extreme habitats like AMD.