Biodegradation of 2,4,6‐trinitrotoluene and hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine by Actinomycetes species, first time isolated and characterized from water, wastewater, and sludge

Abstract

Biodegradation has been applied to remediate explosives contaminants, and bacteria have a high potential for the degradation of explosives, such as hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX) and 2,4,6‐trinitrotoluene (TNT). The present study aims to screen and characterize explosive biodegradable Actinomycetes from water, wastewater, and sludge. Actinomycetes isolates were recovered from 80 environmental samples from diverse environmental resources in explosive contaminated areas of Iran and identified to the genus and species levels using conventional and molecular methods. The growth rate in the presence of pollutants and chromatography was used to determine their biodegradation capability. Twenty‐nine isolates (36.25%) of Actinomycetes were characterized from the cultured samples that belonged to 6 genus and 24 validated species. The most prevalent Actinomycetes isolated were genus Mycobacterium with 11 isolates (37.94%), genus Rhodococcus with seven isolates (24.13%), genus Nocardia with four isolates (13.8%), and genus Streptomyces with three isolates (10.33%). Moreover, our results showed that these isolates could degrade and consume 50–80% of RDX and TNT as their sole carbon and energy source. In conclusion, we showed that Actinomycetes from explosive‐contaminated areas of Iran could degrade TNT and RDX. Hence, seeking and screening untapped ecosystems that possess unexplored Actinomycetes will increase the chances of discovering the resident microorganism that has been capable of degrading TNT and RDX for application in the bioremediation process. The results of this study can be useful in using intact bacteria in nature to eliminate environmental pollution, which is one of the major environmental problems in the world.