Biodegradation of high amounts of phenol, catechol, 2,4-dichlorophenol and 2,6-dimethoxyphenol by Aspergillus awamori cells

The mycelium (or conidia) of Aspergillus awamori NRRL 3112 was investigated for its ability to degrade phenol, catechol, 2,4-dichlorophenol and 2,6-dimethoxyphenol in high concentrations. The biodegradation studies were performed in a liquid medium with the phenolic compounds as a sole carbon and energy source. The organism had mineralized phenol concentration of 0.3 g/l in 60 h, 0.6 g/l in 72 h and 1.0 g/l in 7–8 days. A. awamori had fully degraded catechol concentration of 1.0 g/l in 82 h, 2.0 g/l in 108 h and 3.0 g/l in 124 h. Five days are sufficient for complete biodegradation of 1.0 and 2.0 g/l 2,4-dichlorophenol. The higher concentration of 3.0 g/l was degraded at a rate of 85% for 6 days. The degradation of 2,6-dimethoxyphenol goes slow and only 1.0 g/l concentration was fully degraded for 7 days. In case of 2.0 and 3.0 g/l no complete degradation can be observed even after 8 days of the process. Successfully simulated phenols degradation profiles in all studies were obtained by Haldane-type kinetics. The values of endogenous or decay and yield coefficients for all phenols at different concentrations were also determined.