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Ammonium removal by Agrobacterium sp. LAD9 capable of heterotrophic nitrification–aerobic denitrification

Paper ID Volume ID Publish Year Pages File Format Full-Text
21145 43208 2012 5 PDF Available
Title
Ammonium removal by Agrobacterium sp. LAD9 capable of heterotrophic nitrification–aerobic denitrification
Abstract

Characteristics of ammonium removal by a newly isolated heterotrophic nitrification–aerobic denitrification bacterium Agrobacterium sp. LAD9 were systematically investigated. Succinate and acetate were found to be the most favorable carbon sources for LAD9. Response surface methodology (RSM) analysis demonstrated that maximum removal of ammonium occurred under the conditions with an initial pH of 8.46, C/N ratio of 8.28, temperature of 27.9°C and shaking speed of 150 rpm, where temperature and shaking speed produced the largest effect. Further nitrogen balance analysis revealed that 50.1% of nitrogen was removed as gas products and 40.8% was converted to the biomass. Moreover, the occurrence of aerobic denitrification was evidenced by the utilization of nitrite and nitrate as nitrogen sources, and the successful amplifications of membrane bound nitrate reductase and cytochrome cd1 nitrite reductase genes from strain LAD9. Thus, the nitrogen removal in strain LAD9 was speculated to comply with the mechanism of heterotrophic nitrification coupled with aerobic denitrification (NH4+–NH2OH–NO2−–N2O–N2), in which also accompanied with the mutual transformation of nitrite and nitrate. The findings can help in applying appropriate controls over operational parameters in systems involving the use of this kind of strain.

Keywords
Nitrogen removal; Agrobacterium sp.; Heterotrophic nitrification; Aerobic denitrification; Nitrogen balance analysis; NAP; nirS
First Page Preview
Ammonium removal by Agrobacterium sp. LAD9 capable of heterotrophic nitrification–aerobic denitrification
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 113, Issue 5, May 2012, Pages 619–623
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering