Keywords: Pseudomonas aeruginosa, Pseudomonas fluorescence, growth yield, biomass energetic yield, maintenance coefficient, aerobic biodegradation, phenol, energy
Estimation of the energetic parameters associated with the continuous aerobic biodegradation of phenol by monoculture of Pseudomonas aeruginosa and Pseudomonas fluorescence
The objective of this study was to estimate and analyse the growth parameters of indigenous monoculture of Pseudomonas aeruginosa and Pseudomonas fluorescence on phenol in an aerobic chemostat culture. The biodegradation data were checked for consistency using carbon and available electron balances and growth parameters were estimated using two forms of growth models: reparameterised Pirt's model based on Monod approach and a modified model based on substrate consumption rate. The results showed that the biodegradation data were consistent; growth parameter estimates using the two forms of models were similar and that phenol could be oxidatively metabolised with a maximum of about 35.4%–36% and 31%–33% of the energy contained in it incorporated into the P. aeruginosa and P. fluorescence biomass, respectively. The balance (63%–64.6%) for P. aeruginosa, and (67%–69%) for P. fluorescence, is evolved as heat with little energy needed for the maintenance of the respective organisms.