Abstract

BAUTISTA GARCIA, José Epigmenio et al. Bacterial biodegradability of inhibitors of chiral imine type corrosion and catabolic prediction. Rev. Int. Contam. Ambient [online]. 2015, vol.31, n.4, pp.415-426. ISSN 0188-4999.

Due that the use of common corrosion inhibitor agents usually causes pollution on effluents, because of their non-biodegradability character, in this work we synthesized two chiral compounds of Shiff type base S(-) and Hereafter labelled as Simina, Rimina, SiminaM and RiminaM, derived from the condensation reaction between the 2-pyridincarboxaldehyde and the S(-)-a-methylbenzylamine and the R(+)-a-methyl-benzylamine. These compounds were synthesized by mechanosynthesis and conventional chemical methods. In order to evaluate their biodegradable character, five Gram negative bacteria were previously isolated and identified from a waste water effluent in Pachuca, Hidalgo, Mexico: Psychrobacter phenylpyruvicus, Alcaligenes faecalis, Aeromonas caviae, Citrobacter freundii and Pseudomonas pseudoalcaligenes. The evaluation consisted in cultivating the bacteria in tubes and flasks in presence of the S(-)- and R(+)-imines, while the biodegradation was monitored by UV-Vis and FTIR spectroscopies (by following the intensity decrease of the signals of both the imine and aromatic rings, which are indicative of the loss of the molecular structure). It was found that the inhibitor agents are either individually or in mixture degraded depending on their S(-)- or chirality, being the most susceptible to degradation those compounds synthesized by mechanochemistry. Actually, the Citrobacter freundii bacteria showed the highest ability to degrade all these imines, while the SiminaM compound was the must degraded agent, probably due to its affinity to the bacteria and to the S(-) intramolecular arrangement. On the basis of the results obtained and by applying the analysis in silico, a possible catabolic pathway was predicted.

Keywords : Schiff bases; decomposition; Psychrobacter phenylpyruvicus; Alcaligenes faecalis; Aeromonas caviae; Citrobacter freundii; Pseudomonas pseudoalcaligenes.