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Bacterial growth yields on EDTA, NTA, and their biodegradation intermediates
Zhiwen Yuan1, Jeanne M VanBriesen
1Department of Civil, Environmental, and Architectural Engineering, University of Colorado at Boulder, Engineering Center ECOT 441, UCB 428, Boulder, CO 80309, USA. zhiwen.yuan@colorado.edu
Biodegradation
|April 4, 2007
Summary
This study quantifies microbial growth yields on chelating agents like EDTA and NTA. Researchers measured cell dry weight for mixed cultures and Aminobacter aminovorans, revealing biodegradation pathways and the impact of oxygenase enzymes on cell synthesis.
Area of Science:
- Environmental microbiology
- Biochemistry
- Biotechnology
Background:
- Ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are common synthetic chelating agents found in natural and wastewater.
- Understanding their biodegradation is crucial for environmental remediation and microbial ecology.
Purpose of the Study:
- To systematically measure the growth yields of microbial cultures on EDTA, NTA, and their biodegradation intermediates.
- To investigate the impact of oxygenase enzymes in biodegradation pathways on microbial growth yields.
Main Methods:
- Cultivation of a mixed microbial culture (BNC1-BNC2) on EDTA and its intermediates.
- Cultivation of Aminobacter aminovorans (ATCC 29600) on NTA and its intermediates.
- Measurement of cell dry weight (CDW) per mole of substrate for each culture and substrate combination.
Main Results:
- The BNC1-BNC2 co-culture exhibited varying growth yields on EDTA intermediates, with higher yields on EDTA (75.0 g CDW/mol) and ED3A (68.6 g CDW/mol) compared to glyoxylate (9.7 g CDW/mol).
- A. aminovorans showed growth yields on NTA intermediates, with NTA yielding 44.3 g CDW/mol and glyoxylate yielding 10.4 g CDW/mol.
- Biodegradation pathways involving oxygenase enzymes were identified, and their effect on cell yield was quantified and compared to thermodynamic models.
Conclusions:
- Microbial growth yields on EDTA and NTA vary significantly depending on the specific substrate and microbial culture.
- Oxygenase-catalyzed reactions in biodegradation pathways demonstrably impact microbial energy availability and cell synthesis, quantifiable through experimental measurements and thermodynamic modeling.
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