Sequence analysis of 16S rRNA, gyrB and catA genes and DNA-DNA hybridization reveal that Rhodococcus jialingiae is a later synonym of Rhodococcus qingshengii.

The results of 16S rRNA, gyrB and catA gene sequence comparisons and reasserted DNA-DNA hybridization unambiguously proved that Rhodococcus jialingiae Wang et al. 2010 and Rhodococcus qingshengii Xu et al. 2007 represent a single species. On the basis of priority R. jialingiae must be considered a later synonym of R. qingshengii.

Mycotoxin-degradation profile of Rhodococcus strains.

Mycotoxins are secondary fungal metabolites that may have mutagenic, carcinogenic, cytotoxic and endocrine disrupting effects. These substances frequently contaminate agricultural commodities despite efforts to prevent them, so successful detoxification tools are needed. The application of microorganisms to biodegrade mycotoxins is a novel strategy that shows potential for application in food and feed processing. In this study we investigated the mycotoxin degradation ability of thirty-two Rhodococcus strains on economically important mycotoxins: aflatoxin B1, zearalenone, fumonisin B1, T2 toxin and ochratoxin A, and monitored the safety of aflatoxin B1 and zearalenone degradation processes and degradation products using previously developed toxicity profiling methods. Moreover, experiments were performed to analyse multi-mycotoxin-degrading ability of the best toxin degrader/detoxifier strains on aflatoxin B1, zearalenone and T2 toxin mixtures. This enabled the safest and the most effective Rhodococcus strains to be selected, even for multi-mycotoxin degradation. We concluded that several Rhodococcus species are effective in the degradation of aromatic mycotoxins and their application in mycotoxin biodetoxification processes is a promising field of biotechnology.

Applicability of the functional gene catechol 1,2-dioxygenase as a biomarker in the detection of BTEX-degrading Rhodococcus species.

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.

Comparative biodegradation examination of Pseudomonas aeruginosa (ATCC 27853) and other oil degraders on hydrocarbon contaminated soil.

The soil that we investigated in our experiment was extremly high contaminated with petroleum hydrocarbons. The sample was originated from a former truck factory, next to an oil tank. We tried on this sample three different biodegradation treatments in a soil respirometer. The aim of the experiment was investigate if the clinical strain Pseudomonas aeruginosa ATCC 27853 is able to utilize petroleum hydrocarbons as carbon source. In spite of the relevant literature Pseudomonas aeruginosa ATCC 27853 (clinical isolate, from blood) was proven to be a good oil degrader.