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Research has been conducted on the tetrachloroethene dehalorespiration. The study of this dehalorespiration has been carried in a continuous coculture of the sulfate-reducing bacterium Desulfovibrio fructosivorans and dehalorespirating Desulfitobacterium frappieri TCE1 in the sulfate absence and at various sulfate concentrations and the details are presented.

This article examines the behavior of trinitrotoluene composting in soil/molasses mixtures.

The influence of varied electron donors/acceptors on dehalorespiration of tetrachloroethene by a novel dehalorespiring anaerobe, for which the name Desulfitobacterium frappieri TCE1 is proposed, is discussed. The bacterium is strictly anaerobic. A study was carried out to characterize the novel the dehalorespiring strain and to perform a detailed physiological study of its dehalorespiration. A comparative analysis of tetrachloroethene-dependent growth of the strain and dehalorespiration in some related Desulfitobacterium species was carried out. TCE1 is gram-positive, motile, and shaped like a curved rod with about 6 lateral flagella and is 2-4 by 0.6-0.8 micrometers.

Research results indicate that a two-step anaerobic-aerobic treatment process that incorporates some special procedures during each treatment phase is the most promising process for the biremediation of soils contaminated with the explosive 2,4,6 trinitrotoluene (TNT). Following a nine-week anaerobic-aerobic incubation period, 84% of applied radioactivity was immobilized in various soil fractions.

Almost 84% of the initially applied radioactivity immobilized in different fractions was determined after 9 weeks of anaerobic-aerobic incubation with an optimized experimental setup. On the other hand, 57% of the radioactivity was determined as immobilized in the soil organic matrix after 5 weeks of anaerobic treatment. Humic acid and fulvic acid fraction yielded small amounts of radioactivity after alkaline hydrolysis of the solvent-extracted soil/molasses mixtures was undertaken.

Worldwide plastic production has surged over the past 50 years. In 2016, it reached 335 million tonnes per annum, with Europe alone producing 60 million tonnes. Over the next 20 years, it is expected to double. Plastic packaging is the most important product (26% of the total volume of all plastics used), although it has a short life compared to plastics used in, for example, the construction and car industries. Plastic producers and transformers are keen to highlight the benefits derived from plastic packaging; not only does it deliver direct economic profits, but it also helps prevent food waste and contamination. Further, by lessening the weight of packaging, it can reduce the fuel used in the transport of goods. This is certainly important, but even if these plastics are re-used, they inevitably become waste at some point. If we are to close the loop of the circular economy, this waste needs to be seen as a resource to be plugged back into the life cycle of plastics (PlasticsEurope, 2018). [ABSTRACT FROM AUTHOR]

This review about the genus Gordonia provides a current overview of recent research on a young genus that was introduced in the year 1997 (Stackebrandt et al., 1997). This emerging genus has attracted increasing environmental, industrial, biotechnological and medical interest during the last few years, in particular due to the capabilities of its members to degrade, transform, and synthesize organic compounds as well as to the pathogenic effects that have been described in many case studies. The number of publications about Gordonia has increased significantly after the year 2004 (the year of the first Gordonia review published by Arenskötter et al.) describing 13 new validly published species (type strains), many newly described physiological and metabolic capabilities, new patent applications and many new case reports of bacterial infections. Members of the genus Gordonia are widely distributed in nature and it is therefore important to unravel the species richness and metabolic potential of gordoniae in future studies to demonstrate their environmental impact especially on the degradation of persistent organic compounds and their ecological participation in the carbon cycle of organic material in soil and water. This review summarizes mainly the current state of importance and potential of the members of this genus for the environmental and biotechnological industry ('the strengthsâ) and briefly its pathogenic impact to humans ('the weaknessesâ). [ABSTRACT FROM AUTHOR]

The aerobic degradation of cholesterol, testosterone, androsterone, progesterone, and further steroid compounds as sole carbon source has been observed in the newly isolated bacterial Gram-positive strain Chol-4. The 16S rRNA gene sequence shares the greatest similarity with members of the genus Rhodococcus, with the closest shared nucleotide identities of 98–99% with Rhodococcus ruber (DSM 43338T) and Rhodococcus aetherivorans (DSM 44752T). Phylogenetic analysis of Rhodococcus 16S rRNA gene sequences consistently places strain Chol-4 in a clade shared with those both type strains within the Rhodococcus rhodochrous subclade. The results of DNA–DNA hybridization against its two phylogenetically closest neighbors as well as the results of morphological, physiological, and biochemical tests allowed genotypic and phenotypic differentiation of strain Chol-4 from Rhodococcus ruber (DSM 43338T) on the species level and from the other validly described Rhodococcus species on the genus level. Strain Chol-4 therefore merits recognition as a novel strain of the species Rhodococcus ruber and demonstrates for the first time the capability of this species to utilize a great variety of steroid compounds as growth substrates never shown for other species of this genus so far. The genome of strain Chol-4 harbors at least one gene cluster that may be responsible for the degradation of steroid compounds. This gene cluster was identified in a cloned 5458 bp BamHI– EcoRV DNA fragment and compared to similar genes from other Gram-positive and Gram-negative bacteria described so far. [ABSTRACT FROM AUTHOR]

Investigations were carried out to evaluate the level of incorporation of radiolabeled 2,4,6-trinitrotoluene (TNT) and metabolites into the bacterial biomass of two different bacterial species after cometabolically mediated TNT transformation. Biotransformation experiments with 14C-TNT indicated that TNT was not mineralized; however, carbon derived from TNT became associated with the cells. It was found that more than 42% of the initially applied radiolabel was associated with the cell biomass after cometabolic 14C-TNT transformation with the strictly anerobic Desulfovibrio species strain SHV, whereas with the strictly aerobic Serratia plymuthica species strain B7, 32% of cell-associated 14C activity was measured. The remainder of the radiolabel was present in the supernatants of the liquid cultures in the form of different TNT metabolites. Under anoxic conditions with the Desulfovibrio species, TNT was ultimately transformed to 2,4,6-triaminotoluene (TAT) and both diaminonitrotoluene isomers, whereas under oxic conditions with the Serratia species, TNT was converted to hydroxylaminodinitrotoluenes and aminodinitrotoluenes, with 4-amino-2,6-dinitrotoluene (4ADNT) being the major end product. In both culture supernatants, small amounts of very polar, radiolabeled, but unidentified metabolites were detected. At the end of the experiments approximately 92% and 96% of the originally applied radioactivity was recovered in the studies with the Serratia and Desulfovibrio species, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Rhodococcus ruber strain Chol-4 isolated from a sewage sludge sample is able to grow on minimal medium supplemented with steroids, showing a broad catabolic capacity. This paper reports the characterization of three different 3-ketosteroid-Δ1-dehydrogenases (KstDs) in the genome of R. ruber strain Chol-4. The genome of this strain does not contain any homologues of a 3-keto-5α-steroid-Δ4-dehydrogenase (Kst4d or TesI) that appears in the genomes of Rhodococcus erythropolis SQ1 or Comamonas testosteroni. Growth experiments with kstD2 mutants, either a kstD2 single mutant, kstD2 double mutants in combination with kstD1 or kstD3, or the triple kstD1,2,3 mutant, proved that KstD2 is involved in the transformation of 4-androstene-3,17-dione (AD) to 1,4-androstadiene-3,17-dione (ADD) and in the conversion of 9α-hydroxy-4-androstene-3,17-dione (9OHAD) to 9α-hydroxy-1,4-androstadiene-3,17-dione (9OHADD). kstD2,3 and kstD1,2,3 R. ruber mutants (both lacking KstD2 and KstD3) did not grow in minimal medium with cholesterol as the only carbon source, thus demonstrating the involvement of KstD2 and KstD3 in cholesterol degradation. In contrast, mutation of kstD1 does not alter the bacterial growth on the steroids tested in this study and therefore, the role of this protein still remains unclear. The absence of a functional KstD2 in R. ruber mutants provoked in all cases an accumulation of 9OHAD, as a branch product probably formed by the action of a 3-ketosteroid-9α-hydroxylase (KshAB) on the AD molecule. Therefore, KstD2 is a key enzyme in the AD catabolism pathway of R. ruber strain Chol-4 while KstD3 is involved in cholesterol catabolism. [Copyright &y& Elsevier]

The taxonomic position of the cholesterol-degrading strain Chol-3(T), isolated from a sewage sludge sample, was clarified using a polyphasic taxonomic approach. Phylogenetic analysis of its 16S rRNA gene sequence, whole-cell fatty acid profile and mycolic acid composition revealed that this isolate is a member of the genus Gordonia with the species Gordonia sihwensis, G. hydrophobica and G. shandongensis being the nearest phylogenetic neighbours. The results of DNA-DNA hybridization against its phylogenetically closest neighbours as well as the results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain Chol-3(T) from the other Gordonia species with validly published names. Strain Chol-3(T) therefore merits recognition as a member of a novel species within the genus Gordonia, for which the name Gordonia cholesterolivorans sp. nov. is proposed. The type strain is Chol-3(T) (=CECT 7408(T) =DSM 45229(T)).