Bacteria isolated from explosive contaminated environments transform pentaerythritol tetranitrate (PETN) under aerobic and anaerobic conditions.

This article focuses on the isolation and characterization of bacteria capable of transforming pentaerythritol tetranitrate (PETN), a persistent nitrate ester explosive, under aerobic and anaerobic conditions. Twelve PETN-transforming cultures, including four pure strains and eight co-cultures from explosive-contaminated environments in Colombia, were identified, belonging to diverse taxa within the phyla Proteobacteria and Actinobacteria; notably, this is the first report of PETN transformation by Bradyrhizobium sp., Rhodococcus sp., and Gram-positive Actinobacteria. Under aerobic conditions, PETN biotransformation occurred efficiently only in the presence of additional carbon sources, with up to 91% transformation in two days, accompanied by nitrite release and bacterial growth, whereas anaerobic transformation was demonstrated for the first time by isolated pure and mixed cultures but to a lesser extent (up to ~52% over 157 days). The study suggests that PETN degradation capacity is phylogenetically widespread among bacteria and may be more common than previously recognized, providing insights relevant for bioremediation strategies of explosive-contaminated sites.