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Rhodococcus Sp. (Rhodococcu + sp)

Distribution by Scientific Domains
Life Sciences80%

Selected Abstracts

Application of Exchangeable Biochemical Reactors with Oxidase-Catalase-Co-immobilizates and Immobilized Microorganisms in a Microfluidic Chip-Calorimeter

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 5 2008
M. Leifheit
Abstract Several methods for the quantitative detection of different compounds, e.g., L -amino acids, sugars or alcohols in liquid media were developed by application of an automatic measuring unit including a fluid chip-calorimeter FCC-21. For this purpose, enzymes were immobilized covalently on the inner and outer surface of CPG (controlled porous glass)-spherules with an outer diameter of 100,,m and filled into a micro flow-through reaction chamber (VR = 20,,L). The design of the measuring cell allows for easy insertion into the calorimeter device of a stored series of comfortably pre-fabricated measuring cells. These cells can be filled with different enzyme immobilizates. Different oxidases were used and co-immobilized with catalase for the improvement of the detection sensitivity. A signal amplification could be achieved up to a factor of 3.5 with this configuration. ,- D -glucose, ethanol and L -lysine could be detected in a range of 0.25,1.75,mM using glucose oxidase, alcohol oxidase and lysine oxidase. The group of oxidases in combination with the enzymatic catalysis of the intermediate H2O2 allows the quantitative detection of a large number of analytes. A good measurement and storage stability could be achieved for several weeks by this immobilization method. In addition to enzyme-based detection reactions, it was shown that living microorganisms can be immobilized in the reaction chamber. Thus, the system can be used as a whole-cell biosensor. The quantitative detection of phenol in the range of 10,100,,M could be performed using the actinomycete Rhodococcus sp. immobilized on glass beads by means of embedding into polymers. [source]

Search of Microorganisms that Degrade PAHs under Alkaline Conditions

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2004
A. Gerbeth
Abstract Bacterial strains were enriched from building rubble contaminated with polycyclic aromatic hydrocarbons (PAHs). These strains were studied as an inoculum in bioremediation processes with contaminated building rubble. The selection criteria for the bacteria were broad profiles in PAH degradation, stable expression of the traits and tolerance to alkaline conditions. Various strains of Micrococcus sp., Dietzia sp., Rhodococcus sp. and Pseudomonas sp. met the selection criteria. In general, degradative activity was limited at higher pH values. Strains of Micrococcus were suitable for practical use as complete degradation of various PAHs was observed at pH values exceeding 10. Strains of Dietzia sp. showed broad PAH degradation profile, but in some cases degradation came to a halt leaving some of the PAHs unutilized. With Dietzia sp. this could be due to inhibitory effects from the accumulation of toxic PAH metabolic products and/or growth-limiting media conditions. [source]

New alk genes detected in Antarctic marine sediments

ENVIRONMENTAL MICROBIOLOGY, Issue 3 2009
Emanuele Kuhn
Summary Alkane monooxygenases (Alk) are the key enzymes for alkane degradation. In order to understand the dispersion and diversity of alk genes in Antarctic marine environments, this study analysed by clone libraries the presence and diversity of alk genes (alkB and alkM) in sediments from Admiralty Bay, King George Island, Peninsula Antarctica. The results show a differential distribution of alk genes between the sites, and the predominant presence of new alk genes, mainly in the pristine site. Sequences presented 53.10,69.60% nucleotide identity and 50.90,73.40% amino acid identity to alkB genes described in Silicibacter pomeroyi, Gordonia sp., Prauserella rugosa, Nocardioides sp., Rhodococcus sp., Nocardia farcinica, Pseudomonas putida, Acidisphaera sp., Alcanivorax borkumensis, and alkM described in Acinetobacter sp. This is the first time that the gene alkM was detected and described in Antarctic marine environments. The presence of a range of previously undescribed alk genes indicates the need for further studies in this environment. [source]

Utilization of mixtures of polycyclic aromatic hydrocarbons by bacteria isolated from contaminated sediment

FEMS MICROBIOLOGY ECOLOGY, Issue 1 2002
Deborah Dean-Ross
Abstract The ability of sediment bacteria to utilize polycyclic aromatic hydrocarbons (PAHs) when present as components of mixtures was investigated. One strain, identified as Mycobacterium flavescens, could utilize fluoranthene in the presence of pyrene, although utilization of pyrene was slower in the presence of fluoranthene than in its absence. The second strain, a Rhodococcus species, could utilize fluoranthene in the presence of anthracene, although the presence of fluoranthene slowed the rate of utilization of anthracene. Cometabolism of fluoranthene in these strains was confirmed by the isolation of metabolites of fluoranthene and by kinetic analysis of the rate of utilization of the growth substrate in the presence of fluoranthene. In both strains, metabolism of fluoranthene occurred on the fused ring of the fluoranthene molecule, producing 9-fluorenone-1-carboxylic acid. In the Rhodococcus sp., a second metabolite, a-(carboxymethylene)fluorene-1-carboxylic acid, was identified, indicating that this strain has the capacity to metabolize fluoranthene via ortho as well as meta cleavage. The presence of PAHs in a mixture produces interactive effects which can either increase or decrease the rate of utilization of individual PAHs, results which need to be taken into account when estimating rates of degradation in contaminated environments. [source]

Stereoselective Synthesis of Three Isomers of tert -Butyl 5-Hydroxy-4-methyl-3-oxohexanoate through Alcohol Dehydrogenase-Catalyzed Dynamic Kinetic Resolution

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009
Steffen Lüdeke
Abstract Regioselective reduction of the 5-keto group of tert -butyl 4-methyl-3,5-dioxohexanoate (1) leads to a stereodiad of tert -butyl 5-hydroxy-4-methyl-3-oxohexanoate (2). Alcohol dehydrogenases from Lactobacillus brevis (LBADH), Rhodococcus sp. (RS 1-ADH) and Saccharomyces cerevisiae (YGL157w) reduce 1 under dynamic kinetic resolution conditions, thereby establishing two chiral carbons with a single reduction step. While it had been shown previously that LBADH reduction of 1 stereoselectively leads to syn -(4S,5R)- 2, alcohol dehydrogenase-mediated dynamic kinetic resolution now allows easy access to syn -(4R,5S)- 2 (RS 1-ADH; 97.6% ee, syn:anti=92:8, 66% conversion, 37% isolated yield) and anti -(4S,5S)- 2 (YGL157w; 90% ee, anti:syn=93:7, 64% conversion, 42% isolated yield), as well. Thus three out of four possible stereoisomers were formed selectively upon reduction of 1. [source]