Chemical structure‐based predictive model for methanogenic anaerobic biodegradation potential

Abstract

Many screening-level models exist for predicting aerobic biodegradation potential from chemical structure, but anaerobic biodegradation generally has been ignored by modelers. We used a fragment contribution approach to develop a model for predicting biodegradation potential under methanogenic anaerobic conditions. The new model has 37 fragments (substructures) and classifies a substance as either fast or slow, relative to the potential to be biodegraded in the "serum bottle" anaerobic biodegradation screening test (Organization for Economic Cooperation and Development Guideline 311). The model correctly classified 90, 77, and 91% of the chemicals in the training set (n = 169) and two independent validation sets (n = 35 and 23), respectively. Accuracy of predictions of fast and slow degradation was equal for training-set chemicals, but fast-degradation predictions were less accurate than slow-degradation predictions for the validation sets. Analysis of the signs of the fragment coefficients for this and the other (aerobic) Biowin models suggests that in the context of simple group contribution models, the majority of positive and negative structural influences on ultimate degradation are the same for aerobic and methanogenic anaerobic biodegradation.

A quantitative structure‐activity relationship for predicting metabolic biotransformation rates for organic chemicals in fish

“…Thus many, but not all, of the coefficients are intuitively reasonable. The limitations of fragment contribution methods have been discussed in detail [22] and some examples related to the present study are outlined below.…”

“…Models have been developed to predict chemical transformation and degradation in other compartments of the environment providing valuable screening level information for persistence, exposure, hazard, and risk assessments. For example, there are models to predict pathways, probabilities, and rates of biodegradation by microorganisms [15–17] including a series of models available in the EPI Suite TM software package [18–23]. The Biowin models in EPI Suite have been developed using multiple regressions of selected chemical substructures (molecular fragments or descriptors) and molar mass.…”

Performance-advantaged ether diesel bioblendstock production by a priori design

“…Additionally, EPI Suite and EPA TEST analytics (23) show that in the event of an accidental release, 92% of 4-butoxyheptane would partition into the air column and 7.5% would remain in the soil. Although BIOWIN models do not agree on the potential for aerobic degradability (63), it is unlikely that the 4-butoxyheptane will pose environmental risk due to the low predicted water solubility, and therefore mobility (64). This down-selected compound also has low predicted toxicity (acute or chronic) to humans, as well as low anticipated marine impact with nonbioaccumulative properties (23).…”

Toxicology and Biodegradability of Tier Three Gasoline Blendstocks: Literature Review of Available Data

“…Anaerobic biodegradability was estimated using BIOWIN7, which outputs a numerical probability of biodegradability, with values greater than 0.5 being biodegradable and values less than 0.5 being not readily biodegradable (due to the linear fragment contribution model, results may produce negative values). Additional details of the BIOWIN7 model and linear fragment contribution model are available from Meylan et al (2007).…”