Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10140634 | Journal of Environmental Management | 2018 | 8 Pages |
Abstract
Hexavalent chromium compounds such as chromate and dichromate, commonly designated as Cr (VI) compounds, are widely used heavy metals in different industries and are considered highly toxic to most life forms. Unfortunately, they have become a major pollutant of groundwater and rivers around dichromate using industries. Bioremediation is widely used to decrease the amount of dichromate in wastewater but requires large amounts of precious fresh water. Here we tested two marine micro-algal species, Phaeodactylum tricornutum strain CCY0033 and Navicula pelliculosa strain CCMP543, for their ability of dichromate bioremediation and concomitantly producing lipids that can serve as biofuel. Dichromate tolerance of the strains was investigated under different growth conditions in order to obtain high biomass yields, high lipid accumulation and high dichromate removal from the medium. Both algal strains grew well and produced high biomass in media containing up to 1â¯mg of dichromate per liter. Variations in growth conditions revealed that dichromate removal from the medium correlated positively with biomass yield. Dichromate removal using living cells was in the same order of magnitude as with autoclaved dead cells or when using extracted extracellular polymeric substances (EPS). This suggests biosorption of dichromate to cell-associated polymeric substances as the major mechanism of the bioremediation process. For both strains, optimal dichromate removal and lipid production were achieved at a light intensity of 55â¯Î¼molâ¯mâ2sâ1 and at a sodium nitrate concentration of 3â¯mM. The optimal temperature for dichromate removal and lipid production was 23â¯Â°C for P. tricornutum and 27â¯Â°C for N. pelliculosa. Compared to P. tricornutum strain CCY0033, N. pelliculosa strain CCMP543 produced an overall higher lipid yield under these conditions.
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Authors
Abolghasem Hedayatkhah, Mariana Silvia Cretoiu, Giti Emtiazi, Lucas J. Stal, Henk Bolhuis,