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Aims:  Catechol 1,2‐dioxygenase is a key enzyme in the degradation of monoaromatic pollutants. The detection of this gene is in focus today but recently designed degenerate primers are not always suitable. Rhodococcus species are important members of the bacterial community involved in the degradation of aromatic contaminants and their specific detection could help assess functions and activities in the contaminated environments. To reach this aim, specific PCR primer sets were designed for the detection of Rhodococcus related catechol 1,2‐dioxygenase genes. Methods and Results:  Primers were tested with genetically well‐characterized strains isolated in this study and community DNA samples were used as template for Rhodococcus specific PCR as well. The sequences of the catabolic gene in question were subjected to multiple alignment and a phylogenetic tree was created and compared to a 16S rRNA gene based Rhodococcus tree. A strong coherence was observed between the phylogenetic trees. Conclusions:  The results strongly support the opinion that there was no recent lateral gene transfer among Rhodococcus species in the case of catechol 1,2‐dioxygenase. Significance and Impact of the Study:  In gasoline contaminated environments, aromatic hydrocarbon degrading Rhodococcus populations can be identified based upon the detection and sequence analysis of catechol 1,2‐dioxygenase gene.

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Aflatoxin B1 (AFB1) produced by Aspergillus molds is a genotoxic and carcinogenic mycotoxin. For the elimination of mycotoxins from food and feed, biodetoxification can be a successful tool. The aim of this study was to reveal biodetoxification with the cell-free extracts of Rhodococcus erythropolis NI1 and Rhodococcus rhodochrous NI2, which have been already proved to detoxify AFB1. Extracellular matrices of cultures and also intracellular extracts were applied for detoxification. In both cases, media containing constitutively produced and AFB1-induced enzymes were tested, respectively. The pH tolerance of enzymes in the detoxification was examined at pH 7, 7.5, and 8. The remained genotoxicity was detected by SOS-Chromotest and the AFB1 concentration was measured by high performance liquid chromatography with fluorescence detection. In the extracellular matrix, no reduction of genotoxicity was observed. However, detoxification was completed by intracellular enzymes. In intracellular extracts of both strains, genotoxicity was ceased by the constitutive enzymes within 6 h but induced and constitutive enzymes collectively achieved this result within minutes. Moreover, total biodetoxification was observed at every pH adjustment. Analytical results confirmed >84% degradation potential in each sample. Our results indicate a uniquely fast way for the detoxification of AFB1 with intracellular enzymes of R. erythropolis NI1 and R. rhodochrous NI2.

A novel hydrocarbon-degrading, Gram-negative, obligately aerobic, non-motile, non-sporulating, rod-shaped bacterium, designated strain TBF2/20.2 T , was isolated from a biofilter clean-up facility set up on a hydrocarbon-contaminated site in Hungary. It was characterized by using a polyphasic approach to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate is affiliated with the genus Olivibacter in the family Sphingobacteriaceae. It was found to be related most closely to Olivibacter ginsengisoli Gsoil 060 T (93.3 % 16S rRNA gene sequence similarity). Strain TBF2/20.2 T grew at pH 6-9 (optimally at pH 6.5-7.0) and at 15-42 6C (optimally at 30-37 6C). The major fatty acids were iso-C 15 : 0 (39.4 %), summed feature 3 (iso-C 15 : 0 2-OH and/or C 16 : 1 v7c; 26.0 %), iso-C 17 : 0 3-OH (14.5 %) and C 16 : 0 (4.5 %). The major menaquinone was MK-7 and the predominant polar lipid was phosphatidylethanolamine. The DNA G+C content of strain TBF2/20.2 T was 41.2 mol%. Physiological and chemotaxonomic data further confirmed the distinctiveness of strain TBF2/20.2 T from recognized members of the genus Olivibacter. Thus, strain TBF2/20.2 T is considered to represent a novel species of the genus Olivibacter, for which the name Olivibacter oleidegradans sp. nov. is proposed. The type strain is TBF2/20.2 T (5NCAIM B 02393 T 5CCM 7765 T ).The genus Olivibacter, family Sphingobacteriaceae (Euzéby, 1997), was proposed by Ntougias et al. (2007) and, at the time of writing, comprised four recognized species: Olivibacter sitiensis, isolated from alkaline olive-oil mill wastes (Ntougias et al., 2007), and Olivibacter ginsengisoli, Olivibacter terrae and Olivibacter soli (Wang et al., 2008), isolated from soil of a ginseng field and compost in South Korea. The present study describes the taxonomic characterization of a novel Olivibacter-like bacterial strain, designated TBF2/20.2 T .Strain TBF2/20.2 T was isolated from a clean-up facility at a volatile hydrocarbon-contaminated site in Hungary. A biofilter was used for bioremediation of contaminated groundwater by using ex situ, on-site treatment. A sample was taken from the biofilter and 10 g of the sample was stirred thoroughly for 20 min in 90 ml physiological saline (0.9 %, w/v, NaCl) solution and glass beads. Serial dilutions were made and plated on TGY5 agar plates [per litre distilled water: 5 g tryptone, 2.5 g yeast extract, 5 g glucose (all from BioLab Inc.) and 15 g agar agar (Merck)] and incubated at 30 u C for 72 h. Colonies were selected randomly and subsequently purified twice on TGY5 agar medium at 30 u C.Hydrocarbon degradation was tested on prediluted and sterilized diesel oil solution prepared by a Hungarian accredited analytical laboratory (Wessling Hungary Ltd). To confirm oil degradation, 450 ml of this solution was inoculated with strain TBF2/20.2 T growing in 50 ml TGY5 broth (final volume 500 ml) and incubated for 5 days in a rotary shaker (120 r.p.m.) at 25 u C. Uninoculated solution with the addi...