Journal of Environmental Biology

Chromium (VI) tolerance in two halotolerant strains of Nostoc

Bala Kiran, Nisha Rani and Anubha Kaushik*

Department of Environmental Science and Engineering,

Guru Jambheshwar University of Science and Technology, Hisar-125 001, India

(Received: January 21, 2006 ; Revised received: March 08, 2007 ; Accepted: March 16, 2007)

Abstract: The present study reports on chromium (VI) tolerance of two cyanobacterial strains Nostoc linckia and Nostoc spongiaeforme isolated from salt affected soils using uni-algal and bi-algal systems. Besides distinct halophilism, the two strains exhibited remarkable tolerance to chromium (VI) and revealed 1.2 to 2.8 times more chlorophyll in the presence of the metal. While phycobilins and carotenoids also increased in Nostoc linckia with total dissolved salts (TDS) as well as metal, a decline was observed in Nostoc spongiaeforme in the presence of Cr (VI). Relative algal biomass (as % of control) showed significantly higher values (123-239) in Nostoc linckia in the presence of salt, metal and combination of the two. In Nostoc spongiaeforme it declined in the presence of metal (72-81) but increased in the presence of salts (143-249) and also in the binary systems (121-440). The bi-algal consortium showed relatively less tolerance to salt and metal stress. Nostoc linckia (20 day culture) showed upto 40% chromium removal whereas Nostoc spongiaeforme showed upto 12% removal, indicating greater suitability of the former for use in bioremediation studies.

Key words: Chromium, Total dissolved solids (TDS), Tolerance, Cyanobacteria, Nostoc

PDF of full length paper is available with author (aks_10@yahoo.com)

 

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