Isolation and Characterization of Alkalophilic Denitrifying Bacteria From Lake Chitu
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Date
2008-07-04
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Addis Ababa University
Abstract
The objectives of the study were to isolate and characterize alkaliphilic denitrifying organisms from Ethiopia soda lake, Lake Chitu. Eighty seven potential denitrifying organisms were isolated. Two isolates were selected (designated as BACC280 and BACC118) as efficient denitrifiers for further characterization. These were Gram-negative, oxidase and catalase positive cocci, mesophilic and facultative anaerobe. Isolate BACC118 can optimally grow from 0 to 5% NaCl and 0.25 to 1% Na2CO3 concentration but optimum salt concentration for BACC280 is relatively higher. Salt requirement for denitrification activity of the isolates were found to be similar with growth concentration of NaCl but Na2CO3 optimum was at 0.25% to 2% for BACC280 and 0.5 to 3% for BACC118. The pH optimum of both buffered and un buffered were 12 for BACC280 and BACC118. Both isolates were able to denitrify aerobically and anoxically. These isolates may play great role in recycling of nitrogen compounds in to gaseous end product in their natural habitat. They have also potential to treat wastes that contain high amount of nitrogen, high salt concentration and high pH values.
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Keywords
Denitrifying Bacteria, Soda Lake, Alkalophiles, Halophilis