An estimation of the true growth yields and maintenance coefficients for Comamonas acidovorans DSM 6426 under continuous cultivation on quinoline has been performed. The data were checked for consistency using available electron, carbon and nitrogen balances. The true biomass energetic yields, eta(max), and energetic maintenance coefficients, m(e), were estimated using two models based on control of growth rate and control of substrate uptake rate, respectively. The estimations were converted to the various familiar true growth yield and maintenance units such as substrate-based (Y-X/S(max), m(S/X)), oxygen-based (Y-X/O2(max), m(O2/X)) and carbon dioxide-based (Y-X/CO2(max), m(CO2/X)) units. For the complete mineralization of quinoline by C. acidorvorans, values of eta(max) = 0.371 and m(e) = 0.0426 h(-1) were obtained.