Christen Pierre, Davidson Sylvain, Combet-Blanc Yannick, Auria Richard
Source
Biodegradation, 2011,
22 (3), p. 475-484 ISSN 0923-9820
Toxic at low concentrations, phenol is one of the most common organic pollutants in air and water. In this work, phenol biodegradation was studied in extreme conditions (80A degrees C, pH = 3.2) in a 2.7 l bioreactor with the thermoacidophilic archaeon Sulfolobus solfataricus 98/2. The strain was first acclimatized to phenol on a mixture of glucose (2000 mg l(-1)) and phenol (94 mg l(-1)) at a constant dissolved oxygen concentration of 1.5 mg l(-1). After a short lag-phase, only glucose was consumed. Phenol degradation then began while glucose was still present in the reactor. When glucose was exhausted, phenol was used for respiration and then for biomass build-up. After several batch runs (phenol < 365 mg l(-1)), specific growth rate (mu(X)) was 0.034 +/- A 0.001 h(-1), specific phenol degradation rate (q(P)) was 57.5 +/- A 2 mg g(-1) h(-1), biomass yield (Y-X/P) was 52.2 +/- A 1.1 g mol(-1), and oxygen yield factor (Y-x/o2) was 9.2 +/- A 0.2 g mol(-1). A carbon recovery close to 100% suggested that phenol was exclusively transformed into biomass (35%) and CO2 (65%). Molar phenol oxidation constant (Y-o2/P) was calculated from stoichiometry of phenol oxidation and introducing experimental biomass and CO2 conversion yields on phenol, leading to values varying between 4.78 and 5.22 mol mol(-1). Respiratory quotient was about 0.84 mol mol(-1), very close to theoretical value (0.87 mol mol(-1)). Carbon dioxide production, oxygen demand and redox potential, monitored on-line, were good indicators of growth, substrate consumption and exhaustion, and can therefore be usefully employed for industrial phenol bioremediation in extreme environments.
