Quantitative structure-biodegradation relationship study for biodegradation rates of substituted benzenes by river...

The biodegradation rate constant (K) of 21 substituted phenols, anilines, and benzoic acids was determined by using bacteria from the Songhua River (Jilin Province, China) as an inoculum. All of the compounds studied are readily biodegradable chemicals, as shown by their high K values. The quantitative structure-biodegradation relationship results showed that the biodegradation rate of the studied compounds is related mainly to the heat of formation (Hf) and the negative logarithm of the ionization constant (pKa), whereas no simple relationship exists with the n-octanol-water partition coefficients. The equation K = - 1.127 x 10(-3)Hf - 0.0388pKa + 0.859 was found to fit well (r2(adj) = 0.805), and the correlation coefficient between the predicted and the experimental K values was up to 0.908.