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1.
A bacterium isolated from Assam (India) soil was found to accumulateL-valine in the growth medium and was identified asMicrococcus varians. The strain grew and accumulated valine in a purely synthetic medium, but supplementation with either casamino acids or yeast extract or with both, improved the yield. The entire fermentation period could be divided into a growth phase and a production (phase which could be prolonged by adjustment of pH to neutral range. Among the different hydrocarbon and nitrogen sources tested straight run gas-oil and ammonium sulphate, respectively, were found most suitable. Antibiotics inhibited growth but stimulated extracellular valine accumulation. Vitamins stimulated growth and valine yield and an inoculum level of 10 % was found to be optimal. The yield ofL-valine under optimal conditions was 2.95 g/L.  相似文献   

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A new hydrocarbon isopatchoul-3-ene has been isolated from the essential oil of Cyperus scariosus. The structure and stereochemistry was assigned on the basis of spectroscopic and chemical data. Its biomimetic conversion to isopatchoulenol has been achieved.  相似文献   

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A bacterium isolated from Assam (India) soil was found to accumulate L-lysine in the mineral salt-hydrocarbon medium and identified to be a strain of Micrococcus luteus. The strain is able to grow and accumulate l-lysine in a purely synthetic medium, but supplementation of the synthetic medium with casamino acid or yeast extract or both, improves the yield. The entire fermentation period can be divided into a growth phase and a production phase, which can be prolonged by adjustment of the pH to the neutral range. Among the different hydrocarbon and nitrogen sources tested straight run gas oil (47percnt;) and ammonium sulphate (0.4%), respectively, were found most suitable. Erythromycin at 1 μg/ml level inhibited growth bu¸t stimulated lysine excretion. An inoculum level of 10% (v/v) of the medium was optimal for lysine production. The yield of lysine under optimal conditions was found to be 3.25 g per litre of the medium. Lysine has been isolated in crystalline form from the fermented broth by ion exchange resin chromatography and found to be pure sample of L-isomer.  相似文献   

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During an investigation of Artemisia capillaris, a new acetylenic hydrocarbon, neocapillen, was isolated as a minor component and its structure determined.  相似文献   

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The prevalence of chlorinated hydrocarbon insecticide uptake by chemoorganotrophic bacteria has been investigated. Thirteen bacterial species were observed to sorb and concentrate (bioconcentratc)α-chlordane,β-chlordane, dieldrin, heptachlor epoxide, and lindane from aqueous systems. Bioconcentration, as expressed by the ratio of cellular insecticide in ng/mg (dry wt) to supernatant insecticide in ng/μl, ranged from 10 for lindane byEnterobacter aerogenes to a high of 55,900 forβ-chlordane byCaulobacter vibrioides var.limonus. Amounts of cellular chlorinated hydrocarbon insecticides (CHI) detected and the bioconcentration ratios were observed to have the following order in magnitude:α- orβ-chlordane > dieldrin > heptachlor epoxide > lindane. This decreasing order was the inverse of reported water solubilities for the CHI and the inverse relationship was mathematically defined. The CHI were not easily removed from cells by washing (desorbing) and desorption was directly proportional to insecticide water solubility. Uptake of the CHI was rapid, near-maximum amounts being sorbed within 15 min, and pH 7 appeared optimal for bioconcentration as examined over the range pH 6 to 8. Implications of this investigation are that bioconcentration of CHI by bacteria might serve as a means of introducing these toxic compounds into aquatic food chains and that the bioconcentration phenomenon might lend itself as a treatment procedure for the intentional removal of residual CHI from water supplies and wastewater.  相似文献   

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Marine hydrocarbon seeps introduce large amounts of organic carbon into the environment. Different microorganisms inhabit these unusual environments using the hydrocarbons as an energy source. A recent paper by Kniemeyer et al. shows, for the first time, that sulfate-reducing bacteria isolated from hydrocarbon seeps can oxidize short-chain hydrocarbons anaerobically. This finding is an important contribution to our understanding of the role of microbes in the recycling of chemically inactive carbon compounds.  相似文献   

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A bacterium isolated from Assam (India) soil was found to accumulale l-lysine from hydrocarbon and was identified as a strain of Micrococcus varians. The strain is able to grow and accumulate lysine in a purely synthetic medium though supplementation of the synthetic medium with casamino acids significantly improves the yield. The yield of l-lysine under optimal conditions was found to be 2.6 g X 1(-1) of the compound isolated in crystalline form.  相似文献   

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Water collected at 12 sites in the Neuse River estuary of North Carolina was analyzed for total viable counts on three isolation media (Trypticase soy agar [TSA], marine agar 2216, Sabouraud agar) and total hydrocarbons by fluorescence spectroscopy. Counts of 3.9 X 10(1) to 3.8 X 10(3) cells/ml were found for total heterotrophs, well within the range commonly reported for marine and estuarine waters. Generally, marine agar 2216 gave higher counts than TSA at stations with salinities greater than 6.0 mg/ml; TSA gave higher counts than marine agar 2216 at sites with salinities less than 4.0 mg/ml. The microbial species isolated on the three media agree well with those previously reported for estuarine microbial communities. Water analyses, using XAD-2 resin and fluorescence spectroscopy, revealed petroleum hydrocarbon concentrations in the range of 5 to 79 ng/ml. Representatives of the microbial species isolated from these communities were tested individually for their ability to grow using kerosene as a sole source of carbon and energy. At all but two stations, the majority of the species isolated were able to grow on hydrocarbons, indicating that this ability is widespread even in environments not subjected to high levels of hydrocarbon pollution.  相似文献   

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Polycyclic aromatic hydrocarbon (PAH) o-quinone reductase (PQR) plays a crucial role in the detoxification of PAH o-quinones by reducing them to catechols. Two constitutive PQRs were found in cell extracts of a pyrene-degrading Mycobacterium sp. strain PYR100. The enzymes had an activity towards 9,10-phenanthrenequinone (PQ) and/or 4,5-pyrenequinone (PyQ), and the relative amounts varied with the pH of the culture media. PQR1, containing an FAD cofactor, was a monomer (20.1 kDa), and PQR2, with no flavin cofactor, was a homodimer (26.5 kDa subunits). There was no homology between the N-terminal sequences of PQR1 and PQR2. Dicumarol and quercetin inhibited PQR2 more strongly than PQR1. PQR1 had much lower specificity constants (k(cat)/K(m), 10(5)M(-1)s(-1)) for menadione (0.80) and PQ (5.19) than PQR2 (13.9 for menadione and 176 for PQ). Additionally, PQR2 exhibited a broad substrate specificity with high specificity constants for 1,4-naphthalenequinone, 1,2-naphthalenequinone, and PyQ.  相似文献   

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Aim:  The goal of this study was to identify functional targets to detect polycyclic aromatic hydrocarbon (PAH)-degrading bacterial populations in cold marine ecosystems.
Methods and Results:  We designed a degenerate primer set targeting genes encoding the α subunit of PAH-dioxygenases from Gram-positive bacteria. This primer set was used to amplify gene fragments from metagenomic DNA isolated from Subantarctic marine sediments (Ushuaia Bay, Argentina). These gene fragments were cloned and sequenced. We identified 14 distinct groups of genes, most of them showing significant relatedness with dioxygenases from Gram-positive bacteria of the genera Rhodococcus , Mycobacterium , Nocardioides , Terrabacter and Bacillus . The level of identity with these genes, however, was low to moderate (33–62% at the amino acid level).
Conclusion:  These results indicate the presence of a high diversity of hitherto unidentified dioxygenase genes in this cold polluted environment.
Significance and Impact of the Study:  Subantarctic marine ecosystems are particularly vulnerable to hydrocarbon pollution, and the development of environmental restoration strategies for these environments is pressing. The information obtained in this work will be the starting point for the design of quantitative molecular tools to analyse the abundance and dynamics of these aromatic hydrocarbon-degrading bacterial populations in the marine environment.  相似文献   

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The long-chain saturated and mono-unsaturated hydrocarbon content of the juice sacs of five mandarin cultivars (Mediterranean, Honey, Wilking, Kinnow, King) were examined. Normal homologues accounted for more than 47% of the saturated and more than 75% of the monoene hydrocarbons. In the saturated fraction the major hydrocarbon was n-C25 but in the monoene fraction n-C25 predominated in Kinnow and King while C29 predominated in Mediterranean, Honey and Wilking. All five cultivars could be differentiated from each other and from other citrus species by their hydrocarbon patterns. The noticeably high normal/iso ratios of saturated C23 and C25 hydrocarbons previously shown to be characteristic of mandarin species, Citrus unshiu and C. reticulata, were also found in C. nobilis and C. deliciosa.  相似文献   

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Schizosaccharomyces pombe isolated from palm wine was evaluated for single-cell-protein production using hydrocarbon feedstocks. The isolate was adapted for hydrocarbon utilization by continuous enrichment in a mineral-salts medium containing a mixture of two petroleum fractions, kerosene and diesel. The isolate grew well on the mineral-salts medium containing either kerosene or diesel as sole carbon and energy source. Hydrocarbon degradation using the isolate was demonstrated by gas chromatographic analysis. Optimum growth ofS. pombe was obtained at hydrocarbon feedstock concentrations of 1.5%. The optimum temperature and pH for growth of the yeast were found to be 30 °C and 5.5 respectively. Ammonium sulfate was found to be the most suitable nitrogen source. Total protein content of the hydrocarbon-grown yeast, analyzed by the Kjeldahl method, was high. The yeast was capable of synthesizing all the amino acids tested. These results show the feasibility of usingS. pombe grown on hydrocarbon feedstocks to produce single-cell protein.  相似文献   

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Kuwaiti desert samples contaminated with crude oil contained Bacillus stearothermophilus strains capable of growth on crude oil as a sole source of carbon and energy, obligately at high temperature. No thermophilic oil utilizers were present in water samples collected from the Arabian Gulf. Most of the desert strains had an optimum temperature of 60°C and grew best on pentadecane (C15), hexadecane (C16) and heptadecane (C17). n-Alkanes with shorter and longer chains, n-alkenes, and aromatic hydrocarbons were less readily utilized. Correspondence to: N. A. Sorkhoh  相似文献   

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The widespread problem caused due to petroleum products, is their discharge and accidental spillage in marine environment proving to be hazardous to the surroundings as well as life forms. Thus remediation of these hydrocarbons by natural decontamination process is of utmost importance. Bioremediation is a non-invasive and cost effective technique for the clean-up of these petroleum hydrocarbons. In this study we have investigated the ability of microorganisms present in the sediment sample to degrade these hydrocarbons, crude oil in particular, so that contaminated soils and water can be treated using microbes. Sediments samples were collected once in a month for a period of twelve months from area surrounding Ennore creek and screened for hydrocarbon degrading bacteria. Of the 113 crude oil degrading isolates 15 isolates were selected and cultivated in BH media with 1% crude oil as a sole carbon and energy source. 3 efficient crude oil bacterial isolates Bacillus subtilis I1, Pseudomonas aeruginosa I5 and Pseudomonas putida I8 were identified both biochemically and phylogenetically. The quantitative analysis of biodegradation is carried out gravimetrically and highest degradation rate, 55% was recorded by Pseudomonas aeruginosa I5 isolate.  相似文献   

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