Exploring Electron Density as a Theoretical Basis for the Biotransformation of Phenolic Steroids

The biodegradation of the steroidal estrogens has been examined using Frontier Electron Density (F.E.D.) theory to analyze its predictive capabilities for wastewater treatment systems and special conditions to simulate a specific portion of wastewater treatment. The electron density is calculated using three different methods based on two different basis sets and two different theories. FED theory effectively predicts enzymatic initiating reactions in the biodegradation of the steroidal estrogens. The initiating reactions examined in this study were all shown to occur at high FED positions according to each theory. The toxicity of the steroidal estrogens is also estimated to determine if estrogenicity will decrease throughout the biodegradation pathways. Certain cases indicated that estrogenicity may increase or decrease depending on the type of initiating reaction that occurs conveying the need to examine the toxicity of both the metabolites and the parent compounds