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

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.     

Thermo-Mechanically Assisted Grain Growth in Ti6Al4V Fabricated Using the Powder Bed Additive Manufacturing During High-Temperature Mechanical Testing

Metallurgical and Materials Transactions A - High-temperature mechanical behaviors of metal alloys and the underlying microstructural variations responsible for such behaviors are important areas...     

Advanced Catalyst for CO2 Photo-Reduction: From Controllable Product Selectivity by Architecture Engineering to Improving Charge Transfer Using Stabilized Au Clusters

Despite enormous progress and improvement in photocatalytic CO₂ reduction reaction (CO₂RR), the development of photocatalysts that suppress H₂ evolution reaction (HER), during CO₂RR, remains still a challenge. Here, new insight is presented for controllable CO₂RR selectivity by tuning the architecture of the photocatalyst. Au/carbon nitride with planar structure (p Au/CN) showed high activity for HER with 87% selectivity. In contrast, the same composition with a yolk@shell structure (Y@S Au@CN) exhibited high selectivity of carbon products by suppressing the HER to 26% under visible light irradiation. Further improvement for CO₂RR activity was achieved by a surface decoration of the yolk@shell structure with Au₂₅(PET)₁₈ clusters as favorable electron acceptors, resulting in longer charge separation in Au@CN/Au_c Y@S structure. Finally, by covering the structure with graphene layers, the designed catalyst maintained high photostability during light illumination and showed high photocatalytic efficiency. The optimized Au@CN/Au_c/G Y@S structure displays high photocatalytic CO₂RR selectivity of 88%, where the CO and CH₄ generations during 8 h are 494 and 198 µmol/gcat., respectively. This approach combining architecture engineering and composition modification provides a new strategy with improved activity and controllable selectivity toward targeting applications in energy conversion catalysis.