The biodegradation CATALOGIC 301C model simulates aerobic biodegradation under MITI I (OECD 301C) test conditions. The modelled endpoint is the percentage of theoretical biological oxygen demand on the 28th day (BOD, %). The model consists of a metabolism simulator and an endpoint model. The microbial metabolism is simulated by the rule-based approach. The core parts of the simulator are a set of hierarchically organized transformations and a system of rules that control the application of these transformations. Recursive application of the transformations allows simulation of metabolism and generation of biodegradation pathways. Calculation of the modeled endpoint (BOD, %) is based on the simulated catabolic tree and the material balance of transformations used to build the tree. The mathematical formalism of the model allows also prediction of half-lives and quantities of metabolites on 28th day.
6 483 selected industrial chemicals prioritized in 4 groups based on risk-based criteria were provided for assessment of biodegradation potential. As the model calculations are very computationally demanding, the number of chemicals was reduced by screening the chemicals through the applicability domain of the model. Predictions were performed only for those chemicals from the top two groups that fell in the model domain. This procedure was related to one of the strategies for increasing the reliability of predictions. The biodegradation potential was predicted for 2 541 chemicals and their stable biotransformation products. Additional information such as molecular formulas, logKow was also included.