Effects of substrate induction and added carbon source on phenol degradation by Pseudomonas putida

The specific growth rates of Pseudomonas putida CCRC14365 abstracted from five different phases (lag, log, late-exponential, stationary, and death), along with its specific rates of phenol degradation, were determined. It was found that cells induced with 100 mg·L^-1 of phenol could completely degrade phenol (100 mg·L^-1) within 18 to 26 h, but that it could be degraded within 23 to 33 h when non-induced cultures were used. In addition, cells harvested from the late-exponential phase were the most effective ones for achieving complete consumption of phenol in both adaptation cases. In contrast to non-induced cells, induced cells had lower specific degradation rates for phenol although their specific growth rates were higher. In other words, the substrate-induced cells produced more biomass that enhanced degradation efficiency although they exhibited a lower degradation activity. To offset the toxicity of phenol and the production of more active cells, the effect of an added carbon source, glucose, on phenol degradation was finally investigated using non-induced cells.