Quantifying the Impact of Wastewater Micronutrient Composition on in Situ Growth Activity of Acinetobacter spp.


Batch growth studies with pure cultures of Acinetobacter johnsoniiT and Acinetobacter johnsonii strain 210 on various media formulations were used to examine the effects of micronutrient composition on the growth rate of microbial populations in wastewater treatment systems. On nutrient rich Luria-Bertani medium, both strains of A. johnsonii grew with a doubling time of approximately 30 min. On a defined, minimal medium with acetate as the sole carbon source, the doubling time of A. johnsoniiT was 9.62 h and the doubling time of strain 210a was 2.6 h. Using a synthetic wastewater as a growth medium, the type strain had a doubling time of 56 h and strain 210a had a doubling time of 9.62 h. The concentration and redox state of iron appeared to be the principle growth limiting factors with higher doubling times occurring in media containing ferric iron as compared to ferrous iron. Additionally, grab samples from batch growth experiments were analyzed with oligonucleotide hybridization probes targeting the mature 16S ribosomal RNA (rRNA) and precursor 16S rRNA of Acinetobacter spp. Results showed that the precursor 16S rRNA levels responded more rapidly and to a greater extent than total 16S rRNA levels to changes in the micronutrient composition of the growth media. Precursor 16S rRNA levels increased in both strains when overnight cultures were diluted with fresh media and when micronutrient supplements were added to growing cultures. Our results show that the micronutrient composition of the influent wastewater can have a significant impact on the microbial community structure in wastewater treatment systems.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Carbon; Iron; RNA; Microbial populations; Wastewater treatment; ferric ion; oligonucleotide; RNA 16S; RNA precursor; iron; nitrogen; phosphorus; RNA 16S; activated sludge; microorganism; nutrient; wastewater; Acinetobacter johnsonii; activated sludge; bacterial growth; bacterial strain; bacterium culture; batch reactor; concentration (parameters); conference paper; culture medium; growth rate; in situ hybridization; microbial population dynamics; nonhuman; nutrient; quantitative analysis; sewage effluent; waste water management; bioreactor; chemistry; genetics; oxidation reduction reaction; physiology; population dynamics; sewage; Acinetobacter; Bioreactors; Iron; Nitrogen; Oxidation-Reduction; Phosphorus; Population Dynamics; RNA, Ribosomal, 16S; Waste Disposal, Fluid; Bioreactors; Iron; Nitrogen; Oxidation-Reduction; Phosphorus; Population Dynamics; RNA, Ribosomal, 16S; Acinetobacter; Acinetobacter johnsonii; Bacteria (microorganisms); Luria

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Article - Conference proceedings

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© 2002 IWA Publishing, All rights reserved.

Publication Date

01 May 2002

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