Prediction, biodegradation

Taking into consideration its physico-chemical properties, removal efficiencies, low biodegradability, predicted environmental levels, toxicity, and the need to provide sufficient safety margins for aquatic organisms, the demand for alternative cationic surfactants arose. Since 1991, DTDMAC has been replaced in some European countries due to producer s voluntary initiatives with new quaternary ammonium compounds, the esterquats. These contain an ester function in the hydrophobic chain (Table 1.3) that can be easily cleaved, releasing intermediates that are susceptible to ultimate degradation [24-26]. The effects of the phasing-out and replacement of DTDMAC can be demonstrated by the results of a Swiss study, where the surfactant... 

Cinchona catalysts that fulfill one of these criteria acceptably well have the entry related to that criterion (i.e. either relative molecular mass, number of steps required to make the catalyst, reaction yield, , mole percentage of catalyst, or biodegradability prediction based on rules of thumb broken) represented in bold in Appendix 7. A. Notably, in spite of their natural origin, none of the Cinchona catalysts is completely benign in terms of the rules of thumb for biodegradability, with the best examples (Entries 4 [108] and 31-33 [109, 116]) breaking only two of the rules. 

Baker, J.R., Gamberger, D., Mihelcic, J.R. and Sabljic, A. (2004) Evaluation of artificial intelligence based models for chemical biodegradability prediction. Molecules, 9 (12), 989-1003. 

Howard, P., Meylan, W., Aronson, D., Stiteler, W., Tunkel, J., Comber, M. and Parkerton, T.F. (2005) A new biodegradation prediction model specific to petroleum hydrocarbons. Environ. Toxicol. Chem., 24, 1847-1860. 

Damborsky, J., K. Manova, and M. Kuty, A mechanistic approach to deriving quantitative structure biodegradability relationships. A case study Dehalogenation of haloaliphatic compounds . In Biodegradability Prediction, W. J. G. M. Peijnenburg and J. Damborsky, Eds., Kluwer Academic, Dordrecht, 1996. 

The Acyclic Aliphatic and Monocyclic Aromatic models were developed during an evaluation of other biodegradation prediction models. As Table 12.6 indicates, the two models were developed with seven structural fragments (acyclic aliphatic) and nine structural fragments (monocyclic aromatic) by means of discriminant analysis with MITI test data. 

Geating, J. 1981. Literature study of the biodegradability of chemicals in water. PB 82-1000843 (EPA 600/2-81-175). In Biodegradability Prediction, Advances in and Chemical Interferences with Wastewater Treatment, Vol 1. National Technical Information Service, Springfield, VA. 

Punch, B., Patton, A., Wight, K., Larson, R.J., Masscheleyn, P., and Forney, L., A biodegradability evaluation and simulation system (BESS) based on knowledge of biodegradation pathways, in Biodegradability Prediction, Peijnenburg, W.J.G.M. and J. Damborsky, J., Eds., Kluwer, Dordrecht, The Netherlands, 1996, pp 65-73. 

Willie J. G. M. Peijnenburg and Jiri Damborsky, Biodegradability Prediction. Proceedings of the NATO Advanced Research Workshop on QSAR Biodegradation II QSARs for Biotransformation and Biodegradation, Luhacovice, Czech Republic, 2-3 May 1996, in NATO ASI Series, Ser. 2, Vol. 23, Kluwer, Dordrecht, 1996. 

Loonen H., F. Lindgren, B. Hansen W. Karcher (1996). Prediction of biodegradability from chemical structure. In Peijnenburg W.J.G.M. J. Damborsky (eds.). Biodegradability Prediction. Kluwer Academic Publishers... 

Evaluation of the Biodegradation Predictive Equations in EPA s CHEMDAT6 Model... 

Biodegradation prediction is important for many reasons, some of which have already been mentioned to fill the gap between known chemical compounds and known metabolism to help design environmentally safe molecules to steer the chemical analysis in degradation route studies and to know more about the fate of chemicals in the environment. 

In this context, it is important to recognize that the biodegradation of organic compounds in the environment is very complex. Whitman et al. [37] have estimated that on the order of 10 bacteria exist on earth. This represents a mass comparable to that of all the green plants on earth. Studies of extracted environmental DNA also show enormous species diversity in bacteria [38]. Perhaps 10 bacterial species were demonstrated in 1 g of typical soil. With such enormity and complexity, how can one reasonably improve on current biodegradation prediction ... 

It is necessary to acknowledge our lack of knowledge of all biodegradation reactions, and the subtle influence of specific environmental conditions on biodegradation. In light of this, biodegradation prediction will never be perfect, but it is perfectible. 

Biowin7 (Anaerobic Model Prediction) Does Not Biodegrade Fast Ready Biodegradability Prediction NO... 

Figure 1 A broad overview of BESS s structure (reproduced from W. Peijnenburg and Jm Damborsicy, Biodegradability Prediction , Kluwer Academic Publishers, 1996, p. 69)...

GAMBETAL makes its biodegradability prediction for a new compound by checking the three simple rules of its knowledge base. 

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