Fe(III) mineral reduction followed by partial dissolution and reactive oxygen species generation during 2,4,6-trinitrotoluene transformation by the aerobic yeast Yarrowia lipolytica

Abstract

Understanding the factors that influence pollutant transformation in the presence of ferric (oxyhydr)oxides is crucial to the efficient application of different remediation strategies. In this study we determined the effect of goethite, hematite, magnetite and ferrihydrite on the transformation of 2,4,6-trinitrotoluene (TNT) by Yarrowia lipolytica AN-L15. The presence of ferric (oxyhydr)oxides led to a small decrease in the rate of TNT removal. In all cases, a significant release of NO2− from TNT and further NO2− oxidation to NO3− was observed. A fraction of the released NO2− was abiotically decomposed to NO and NO2, and then NO was likely oxidized abiotically to NO2 by O2. ESR analysis revealed the generation of superoxide in the culture medium; its further protonation at low pH resulted in the formation of hydroperoxyl radical. Presumably, a fraction of NO released during TNT degradation reacted with superoxide and formed peroxynitrite, which was further rearranged to NO3− at the acidic pH values observed in this study. A transformation and reduction of ferric (oxyhydr)oxides followed by partial dissolution (in the range of 7–86% of the initial Fe(III)) were observed in the presence of cells and TNT. Mössbauer spectroscopy showed some minor changes for goethite, magnetite and ferrihydrite samples during their incubation with Y. lipolytica and TNT. This study shows that i) reactive oxygen and nitrogen species generated during TNT transformation by Y. lipolytica participate in the abiotic conversion of TNT and ii) the presence of iron(III) minerals leads to a minor decrease in TNT transformation.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-014-0094-z) contains supplementary material, which is available to authorized users.

Comparison of intestinal bacterial and fungal communities across various xylophagous beetle larvae (Coleoptera: Cerambycidae)

“…Many wood-feeding insects also have obligate external associations with filamentous fungi and inoculate fungal cells into the food sources, where fungi convert the lignocellulose and serve other nutritional roles 7 . Recently several carrion beetles have been reported to harbor a diversity of ascomycetous yeasts closely related to Yarrowia lipolytica ( Yarrowia -related symbionts) 23 , 56 , which represents as a major biotechnological interest for production of organic acids and bioremediation of contaminated environments 57 , 58 .…”

Fungal, Bacterial, and Archaeal Diversity in the Digestive Tract of Several Beetle Larvae (Coleoptera)

“…In case of xylophagous R. inquisitor larvae, only several ascomycetous yeasts strains could be isolated from their gut content in previous work performed by Grünwald et al [ 3 ]. Several carrion beetles have also been reported to harbor a diversity of ascomycetous yeasts closely related to Yarrowia lipolytica [ 6 ], which is represented as major biotechnological interest for bioremediation of contaminated environments [ 72 , 73 ]. Several other filamentous fungi and yeasts observed in the guts content of Rhagium were also detected in several other environments (including soil, woody substrates, and beetles' gut systems) and might be involved in transformation of various types of substrates (carbohydrates, proteins, and lipids).…”

Draft genome sequence of Brevibacterium epidermidis EZ-K02 isolated from nitrocellulose-contaminated wastewater environments

“…Such industrial wastes are represented by large amounts of wastewaters contaminated with different dissolved chemical compounds and nitrocellulose powder particles. Also, these microbes are of high importance for the development of effective bioremediation strategies of various polluted environments [1] , [2] , [3] . The bacterium optimally grown on LB agar at +30 °C had been cultivated for 24–48 hours.…”