Efficient harvesting of Chlorella pyrenoidosa and Scenedesmus obliquus cultivated in urban sewage by magnetic flocculation using nano-Fe3O4 coated with polyethyleneimine

Water is one of the major products of nature used enormously by human beings and it is not unnatural that any growing community generates enormous waste water or sewage. As a clean environment is a prerequisite for a healthy living in any urban settlement, proper treatment and safe disposal of sewage call for prime attention. Untreated waste water can cause pollution of surface and ground waters. Many new developments in the field of sewage treatment are eventually taking place. These developments include improvements for more effective removal of pollutants and new treatment processes capable of removing pollutants not ordinarily removed by conventional methods. Three types of textile wastewaters (Acid Yellow dye, Acid orange dye and Basic pink dye) has been used for wastewater treatment and microalgal (Chlorella pyrenoidosa and Scenedesmus obliquus) biofuel production. Nitrogen content in textile wastewaters is very less, hence urea is used as nitrogen source in wastewater. Discharge of untreated domestic and industrial wastewater into aquatic bodies is posing a serious eutrophication threat, leading to a slow degradation of the water resources. A number of physical, chemical and biological methods have been developed for the treatment of wastewaters; among these, the use of microalgae is considered as a more eco-friendly and economical approaches.

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Sublethal effects of the insecticide fenitrothion on freshwater phytopiankton

Canadian Journal of Botany ◽

10.1139/b95-006 ◽

1995 ◽

Vol 73 (1) ◽

pp. 45-53 ◽

Cited By ~ 10

Author(s):

Robert A. Kent ◽

Pierre-Yves Caux

Keyword(s):

Chlamydomonas Reinhardtii ◽

Sublethal Effects ◽

Scenedesmus Obliquus ◽

Total Lipid Content ◽

Chlorella Pyrenoidosa ◽

Selenastrum Capricornutum ◽

Total Lipids ◽

Fatty Acid Profiles ◽

Bioconcentration Factors ◽

Ankistrodesmus Falcatus

The effects of the insecticide fenitrothion (O,O-dimethyl-O-(3-methyl-4-nitrophenyl)phosphorothioate) were investigated on the unicellular phytoplankton Ankistrodesmus falcatus, Chlamydomonas reinhardtii, Chlamydomonas segnis, Chlorella pyrenoidosa, Navicula sp., Scenedesmus obliquus, Selenastrum capricornutum, and Staurastrum sp. at concentrations of 0.1, 1.0, and 10 mg∙L−1. Following a 24-h exposure, total lipids, fatty acid profiles, and bioaccumulation of fenitrothion into algal cells were determined for the above species. Total lipids may play an important role in determining sensitivity of phytoplankton to fenitrothion stress over 96-h exposures. A saturation occurred in A. falcatus membranes represented by the 5.4 and 4.3% increases in palmitic (16:0) and oleic (18:1) acids, respectively, and 1.8 and 7.6% decreases in linoleic (18:2) and linolenic (18:3) acids, respectively. This resulted in a shift from a profile dominated by linolenic (18:3) acid to one dominated by the more saturated oleic (18:1) acid. Bioconcentration factors (BCF), or the ratio of the total radiocarbon associated with algae, calculated for viable Chlamydomonas reinhardtii and Chlamydomonas segnis cells were 293 and 124, respectively. BCFs for dead cells were 1261 and 1025 for the same species, respectively. These investigations showed differential insecticide bioaccumulation between species. This bioaccumulation was shown to be correlated with the total lipid content of algal cells. Key words: algae, fatty acids, fenitrothion, lipids, pesticide.

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