| Utilization of hydrophobic bacterium Rhodococcus opacus B-4 as whole-cell catalyst in anhydrous organic solvents.
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Yamashita S.,Satoi M.,Iwasa Y.,Honda K.,Sameshima Y.,Omasa T.,Kato J.,Ohtake H.
Appl. Microbiol. Biotechnol. 74 (2007) 761-7 [PMID: 17123076] Abstract
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| Abstract: Rhodococcus opacus strain B-4, which has recently been isolated as an organic solvent-tolerant bacterium, has a high hydrophobicity and exhibits a high affinity for hydrocarbons. This bacterium was able to survive for at least 5 days in organic solvents, including n-tetradecane, oleyl alcohol, and bis(2-ethylhexyl) phthalate (BEHP), which contained water less than 1% (w/v). The biocatalytic ability of R. opacus B-4 was demonstrated in the essentially nonaqueous BEHP using indigo production from indole as a model conversion. By the catabolism of oleic acid for NADH regeneration, indigo production increased up to 71.6 microg ml(-1) by 24 h. |
| The complete genome of Rhodococcus sp. RHA1 provides insights into a catabolic powerhouse.
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McLeod MP.,Warren RL.,Hsiao WW.,Araki N.,Myhre M.,Fernandes C.,Miyazawa D.,Wong W.,Lillquist AL.,Wang D.,Dosanjh M.,Hara H.,Petrescu A.,Morin RD.,Yang G.,Stott JM.,Schein JE.,Shin H.,Smailus D.,Siddiqui AS.,Marra MA.,Jones SJ.,Holt R.,Brinkman FS.,Miyauchi K.,Fukuda M.,Davies JE.,Mohn WW.,Eltis LD.
Proc. Natl. Acad. Sci. U.S.A. 103 (2006) 15582-7 [PMID: 17030794] Abstract
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| Abstract: Rhodococcus sp. RHA1 (RHA1) is a potent polychlorinated biphenyl-degrading soil actinomycete that catabolizes a wide range of compounds and represents a genus of considerable industrial interest. RHA1 has one of the largest bacterial genomes sequenced to date, comprising 9,702,737 bp (67% G+C) arranged in a linear chromosome and three linear plasmids. A targeted insertion methodology was developed to determine the telomeric sequences. RHA1's 9,145 predicted protein-encoding genes are exceptionally rich in oxygenases (203) and ligases (192). Many of the oxygenases occur in the numerous pathways predicted to degrade aromatic compounds (30) or steroids (4). RHA1 also contains 24 nonribosomal peptide synthase genes, six of which exceed 25 kbp, and seven polyketide synthase genes, providing evidence that rhodococci harbor an extensive secondary metabolism. Among sequenced genomes, RHA1 is most similar to those of nocardial and mycobacterial strains. The genome contains few recent gene duplications. Moreover, three different analyses indicate that RHA1 has acquired fewer genes by recent horizontal transfer than most bacteria characterized to date and far fewer than Burkholderia xenovorans LB400, whose genome size and catabolic versatility rival those of RHA1. RHA1 and LB400 thus appear to demonstrate that ecologically similar bacteria can evolve large genomes by different means. Overall, RHA1 appears to have evolved to simultaneously catabolize a diverse range of plant-derived compounds in an O(2)-rich environment. In addition to establishing RHA1 as an important model for studying actinomycete physiology, this study provides critical insights that facilitate the exploitation of these industrially important microorganisms. |
| Isolation and characterization of benzene-tolerant Rhodococcus opacus strains.
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Na KS.,Kuroda A.,Takiguchi N.,Ikeda T.,Ohtake H.,Kato J.
J. Biosci. Bioeng. 99 (2005) 378-82 [PMID: 16233805] Abstract
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| Abstract: Twenty-two benzene-utilizing bacteria were isolated from soil samples. Among them, three isolates were highly tolerant to benzene. They grew on benzene when liquid benzene was added to the basal salt medium at 10--90% (v/v). Taxonomical analysis identified the benzene-tolerant isolates as Rhodococcus opacus. One of the benzene-tolerant isolates, designated B-4, could utilize many aromatic and aliphatic hydrocarbons including benzene, toluene, styrene, xylene, ethylbenzene, propylbenzene, n-octane and n-decane as sole sources of carbon and energy. Strain B-4 grew well in the presence of 10% (v/v) organic solvents that it was capable of using as growth substrates. Genetic analysis revealed the benzene dioxygenase pathway is involved in benzene catabolism in strain B-4. A deletion-insertion mutant defective in the benzene dioxygenase large and small subunits genes (bnz A 1 and bnz A 2) was as tolerant to organic solvents as the wild-type strain B-4, suggesting that utilization or degradation of organic solvents is not essential for the organic solvent tolerance of R. opacus B-4. |
