A simple 14C-respirometric method for assessing microbial catabolic potential and organic contaminant bioavailability

Brian J. Reid, Christopher J. A. MacLeod, Philip H. Lee, Alistair W. J. Morriss, Joanna D. Stokes, Kirk T. Semple

Research output: Contribution to journalArticlepeer-review


This paper describes the validation and application of a simple flask-based 14C-respirometer system designed to assess mineralisation of 14C-labelled substrates under defined conditions. Validation of this respirometer system indicated stoichiometric CO2 trapping up to a maximum of 400 µmol of CO2 (in a single trap). Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were used to measure growth-linked biodegradation of [14C]naphthalene to 14CO2. A 14C activity balance of 101.7±8.9% (n=6), after 74 h incubation time and 10 respirometer-opening events, indicated the suitability of the system for monitoring substrate mineralisation. This respirometric apparatus was then successfully applied to assess: (i) the PAH catabolism of microbes in a field contaminated soil, where naphthalene and phenanthrene were rapidly mineralised and (ii) soil-associated organic contaminant bioavailability, where increased soil–phenanthrene contact time resulted in a reduction in phenanthrene mineralisation in the soil. The described respirometer system differs from existing respirometer systems in that the CO2 trap can be removed and replaced quickly and easily. The system is efficient, reproducible, adaptable to many situations, easy to construct and simple to use, it therefore affords advantages over existing systems.
Original languageEnglish
Pages (from-to)141-146
Number of pages6
JournalFEMS Microbiology Letters
Issue number2
Publication statusPublished - 2001

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