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1.
Manoj Kumar Vladimir León Angela De Sisto Materano Olaf A. Ilzins 《World journal of microbiology & biotechnology》2007,23(2):211-220
A Bacillus sp. strain DHT, isolated from oil-contaminated soil, grew and produced biosurfactant when cultured in variety of substrate
at salinities of up to 100 g l−1 and temperatures up to 45°C. It was capable of utilizing crude oil, fuels, various pure alkanes and PAHs as a sole carbon
and energy source across a wide range of temperature and salinity. Over the range evaluated, the degradation of hydrocarbon
and biosurfactant production was not influenced by salinity (0–10% wv−1) and temperature (30–45°C). The biosurfactant produced by the organism emulsified a range of hydrocarbons with hexadecane
as the best substrate and toluene as the poorest. From 16S rDNA analysis, strain DHT was related to Bacillus licheniformis. 相似文献
2.
Pratiksha Bhadauriya Radha Gupta Surendra Singh Prakash Singh Bisen 《World journal of microbiology & biotechnology》2008,24(1):139-141
n-Alkanes pattern in response to NaCl stress has been studied in the cyanobacterium Anabaena cylindrica. Saturated hydrocarbons were separated and identified by gas chromatography-mass spectrometry (GC-MS) using serially coupled
capillary column. Light chain n-alkanes in the range of C9–C17 (43%) and heavy chain n-alkanes in range of C17–C23 (34%) and C23–C31 (23%) were identified as the major components of total hydrocarbons in the NaCl adapted cells of A. cylindrica. In contrast, NaCl-untreated cells of A. cylindrica had dominance of only long chain n-alkanes in the range of C23–C31 comprising about 94% of its total n-alkanes. The persistence of high level (43%) of short chain n-alkanes (C9–C17) in NaCl adapted cells of A. cylindrica as compared to its negligible level (0.2%) in NaCl untreated counterpart clearly indicates that NaCl stress causes the A. cylindrica to shift towards the synthesis of short chain n-alkanes. 相似文献
3.
Farrakh Mehboob Howard Junca Gosse Schraa Alfons J. M. Stams 《Applied microbiology and biotechnology》2009,83(4):739-747
Microbial (per)chlorate reduction is a unique process in which molecular oxygen is formed during the dismutation of chlorite.
The oxygen thus formed may be used to degrade hydrocarbons by means of oxygenases under seemingly anoxic conditions. Up to
now, no bacterium has been described that grows on aliphatic hydrocarbons with chlorate. Here, we report that Pseudomonas chloritidismutans AW-1T grows on n-alkanes (ranging from C7 until C12) with chlorate as electron acceptor. Strain AW-1T also grows on the intermediates of the presumed n-alkane degradation pathway. The specific growth rates on n-decane and chlorate and n-decane and oxygen were 0.5 ± 0.1 and 0.4 ± 0.02 day−1, respectively. The key enzymes chlorate reductase and chlorite dismutase were assayed and found to be present. The oxygen-dependent
alkane oxidation was demonstrated in whole-cell suspensions. The strain degrades n-alkanes with oxygen and chlorate but not with nitrate, thus suggesting that the strain employs oxygenase-dependent pathways
for the breakdown of n-alkanes. 相似文献
4.
Jayanta Chakrabarti Sabyasachi Chatterjee Sisir Ghosh Narayan Chandra Chatterjee Sikha Dutta 《Current microbiology》2010,61(3):203-209
A novel Acinetobacter strain, Ud-4, possessing a strong capacity to degrade edible, lubricating, and heavy oil was isolated from seawater in a
fishing port located in Toyama, Japan. It was identified by morphological and physiological analyses and 16S rDNA sequencing.
This strain could utilize five types of edible oils (canola oil, olive oil, sesame oil, soybean oil, and lard), lubricating
oil, and C-heavy oil as the sole carbon source for growth in M9 medium. The strain grew well and heavily degraded edible oils
in Luria–Bertani medium during a 7-day culture at 25°C; it also degraded all kinds of oils in artificial seawater medium for
marine bacteria. Furthermore, this strain was capable of degrading almost all C10–C25 n-alkanes in C-heavy oil during a 4-week culture. Oligonucleotide primers specific to two catabolic genes involved in the degradation
of n-alkanes (Acinetobacter sp. alkM) and triglyceride (Acinetobacter sp. lipA) allowed amplification of these genes in strain Ud-4. To our knowledge, this is the first report on the isolation of a bacterium
that can efficiently degrade both edible and mineral oils. 相似文献
5.
A methanogen, strain AK-1, was isolated from permanently cold marine sediments, 38- to 45-cm below the sediment surface at
Skan Bay, Alaska. The cells were highly irregular, nonmotile coccoids (diameter, 1 to 1.2 μm), occurring singly. Cells grew
by reducing CO2 with H2 or formate as electron donor. Growth on formate was much slower than that on H2. Acetate, methanol, ethanol, 1- or 2-propanol, 1- or 2-butanol and trimethylamine were not catabolized. The cells required
acetate, thiamine, riboflavin, a high concentration of vitamin B12, and peptones for growth; yeast extract stimulated growth but was not required. The cells grew fastest at 25 °C (range 5
°C to 25 °C), at a pH of 6.0 – 6.6 (growth range, pH 5.5 – 7.5), and at a salinity of 0.25 – 1.25 M Na+. Cells of this and other H2-using methanogens from saline environments metabolized H2 to a very low threshold pressure (less than 1 Pa) that was dependent on the methane partial pressure. We propose that the
threshold pressure may be limited by the energetics of catabolism. The sequence of the 16S rDNA gene of strain AK-1 was most
similar (98%) to the sequences of Methanogenium cariaci JR-1 and Methanogenium frigidum Ace-2. DNA–DNA hybridization between strain AK-1 and these two strains showed only 34.9% similarity to strain JR-1 and 56.5%
similarity to strain Ace-2. These analyses indicated strain AK-1 should be classified as a new species within the genus Methanogenium. Phenotypic differences between strain AK-1 and these strains (including growth temperature, salinity range, pH range, and
nutrient requirements) support this. Therefore, a new species, Methanogenium marinum, is proposed with strain AK-1 as type strain.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
Yin Li Zhiqiang Liu Fengjie Cui Yingying Xu Hui Zhao 《World journal of microbiology & biotechnology》2007,23(6):837-843
A new strain of Penicillium sp. ZH-30 that produces xylanase was isolated from soil. According to the morphology and comparison of internal transcribed
spacer (ITS) rDNA gene sequence, the strain Penicillium sp. ZH-30 was identified as a strain of Penicillium oxalicum. When xylan or wheat bran was used as substrate at 30°C for 3 days under submerged cultivation, xylanase production was 5.3
and 13.3 U ml−1, respectively. The temperature and pH for optimum activity were 50°C and 5.0–6.0, respectively. 相似文献
7.
In this study biodegradation of hydrocarbons in thin oil films was investigated in seawater at low temperatures, 0 and 5 °C.
Heterotrophic (HM) or oil-degrading (ODM) microorganisms enriched at the two temperatures showed 16S rRNA sequence similarities
to several bacteria of Arctic or Antarctic origin. Biodegradation experiments were conducted with a crude mineral oil immobilized
as thin films on hydrophobic Fluortex adsorbents in nutrient-enriched or sterile seawater. Chemical and respirometric analysis
of hydrocarbon depletion showed that naphthalene and other small aromatic hydrocarbons (HCs) were primarily biodegraded after
dissolution to the water phase, while biodegradation of larger polyaromatic hydrocarbons (PAH) and C10–C36 n-alkanes, including n-hexadecane, was associated primarily with the oil films. Biodegradation of PAH and n-alkanes was significant at both 0 and 5°C, but was decreased for several compounds at the lower temperature. n-Hexadecane biodegradation at the two temperatures was comparable at the end of the experiments, but was delayed at 0°C. Investigations
of bacterial communities in seawater and on adsorbents by PCR amplification of 16S rRNA gene fragments and DGGE analysis indicated
that predominant bacteria in the seawater gradually adhered to the oil-coated adsorbents during biodegradation at both temperatures.
Sequence analysis of most DGGE bands aligned to members of the phyla Proteobacteria (Gammaproteobacteria) or Bacteroidetes. Most sequences from experiments at 0°C revealed affiliations to members of Arctic or Antarctic consortia, while no such
homology was detected for sequences from degradation experiment run at 5°C. In conclusion, marine microbial communities from
cold seawater have potentials for oil film HC degradation at temperatures ≤5°C, and psychrotrophic or psychrophilic bacteria
may play an important role during oil HC biodegradation in seawater close to freezing point. 相似文献
8.
Notonecta unifasciata Guerin eggs maintained at different stages of embryonic development in water at variable temperatures (2.2–25.6 °C) and for
periods of 4–12 weeks revealed maximum viability (>80 %) at the highest temperature. However, optimum nondevelopmental viability
was at 14.4 °C with eight-day-old embryos (>35 %). Short term (4 weeks) storage at 14.4 °C significantly increased egg viability.
Survival was poor (<20 %) at the 2 lowest temperatures. Eggs held at 14.4 °C for 12 weeks and sustainingca. 50 % mortality, may be a practical procedure for biological control.
相似文献
9.
Manoj Kumar Vladimir León Angela De Sisto Materano Olaf A. Ilzins Luis Luis 《World journal of microbiology & biotechnology》2008,24(7):1047-1057
A hydrocarbon degrading and biosurfactant producing, strain DHT2, was isolated from oil-contaminated soil. The organism grew
and produced biosurfactant when cultured in variety of substrates at salinities up to 6 g l−1 and temperatures up to 45°C. It was capable of utilizing crude oil, fuels, alkanes and PAHs as carbon source across the wide
range of temperature (30–45°C) and salinity (0–6%). Over the range evaluated, the salinity and temperature did not influence
the degradation of hydrocarbon and biosurfactant productions. Isolate DHT2 was identified as Pseudomonas aeruginosa by analysis of 16S rRNA sequences (100% homology) and biochemical analysis. PCR and DNA hybridization studies revealed that
enzymes involved in PAH metabolism were related to the naphthalene dioxygenase pathway. Observation of both tensio-active
and emulsifying activities indicated that biosurfactants were produced by DHT2 during growth on both, water miscible and immiscible
substrates, including PAH. The biosurfactants lowered the surface tension of medium from 54.9 to 30.2 dN/cm and formed a stable
emulsion. The biosurfactant produced by the organism emulsified a range of hydrocarbons with hexadecane as best substrate
and toluene was the poorest. These findings further indicate that the isolate could be useful for bioremediation and bio-refining
application in petroleum industry. 相似文献
10.
Yan Zhen Mei Bing Fang He Ping Kai Ouyang 《World journal of microbiology & biotechnology》2008,24(3):375-381
Bacillus fordii MH602 was newly screened from soil at 45 °C and exhibited high activities of hydantoinase and carbamoylase, efficiently yielding
l-amino acids including phenylalanine, phenylglycine and tryptophan with the bioconversion yield of 60–100% from the corresponding
dl-5-substituted hydantoins. Hydantoinase activity was found to be cell-associated and inducible. The optimal inducer was dl-5-methylhydantoin with concentration of 0.014 mol L−1 and added to the fermentation medium in the exponential phase of growth. In the production of optically pure amino acids
from dl-5-benylhydantoin, the optimal temperature and pH of this reaction were 45–50 °C and 7.5 respectively. The hydantoinase was
non-stereoselective, while carmbamoylase was l-selective. The hydantoinase activity was not subject to substrate inhibition, or product inhibition by ammonia. In addition,
The activities of both enzymes from crude extract of the strain were thermostable; the hydantoinase and carbamoylase retained
about 90% and 60% activity after 6 h at 50 °C, respectively. Since reaction at higher temperature is advantageous for enhancement
of solubility and for racemization of dl-5-substituted hydantoins, the relative paucity of l-selective hydantoinase systems, together with the high level of hydantoinase and carbamoylase activity and unusual substrate
selectivity of the strain MH602, suggest that it has significant potential applications. 相似文献
11.
Streptomyces luteogriseus strain 099, producing a new type of macrolide antibiotic with anti-coxB6 virus and anti-HIV protease activities, was isolated
from soil. PCR was optimized to amplify β-ketoacyl-ACP synthase (KS) genes. The system was optimized around the use of higher concentrations of DMSO (15% vs. 10% v/v)
and dNTP (500 μM vs. 50–200 μM) and a lower annealing temperature (55 °C vs. 60–70 °C) than the normal PCR method used to amplify high GC content DNA. 相似文献
12.
Crisla S. Souza Daniel Thomaz Elaine R. Cides Karen F. Oliveira João O. Tognolli Cecilia Laluce 《World journal of microbiology & biotechnology》2007,23(12):1667-1677
This work investigated the effects of increasing temperature from 30°C to 47°C on the physiological and genetic characteristics
of Saccharomyces cerevisiae strain 63M after continuous fermentation with cell recycling in a system of five reactors in series. Steady state was attained
at 30°C, and then the temperature of the system was raised so it ranged from 35°C in the last reactor to 43°C in the first
reactor or feeding reactor with a 2°C difference between reactors. After 15 days at steady state, the temperature was raised
from 37°C to 45°C for 25 days at steady state, then from 39°C to 47°C for 20 days at steady state. Starter strain 63M was
a hybrid strain constructed to have a MAT
a/α, LYS/lys, URA/ura genotype. This hybrid yeast showed vigorous growth on plates at 40°C, weak growth at 41°C, positive assimilation of melibiose, positive
fermentation of galactose, raffinose and sucrose. Of 156 isolates obtained from this system at the end of the fermentation
process, only 17.3% showed the same characteristics as starter strain 63M. Alterations in mating type reaction and in utilization
of raffinose, melibiose, and sucrose were identified. Only 1.9% of the isolates lost the ability to grow at 40°C. Isolates
showing requirements for lysine and uracil were also obtained. In addition, cell survival was observed at 39–47°C, but no
isolates showing growth above 41°C were obtained. 相似文献
13.
The effects of nitrogen (N) fertilisation and elevated [CO2] on lipid biosynthesis and carbon isotope discrimination in birch (Betula pendula Roth.) transplants were evaluated using seedlings grown with and without N fertiliser, and under two concentrations of atmospheric
CO2 (ambient and ambient+250 μmol mol-1) in solar dome systems. N fertilisation decreased n-fatty acid chain length (18:0/16:0) and the ratios of α-linolenate (18:2)/linoleate (18:1), whereas elevated [CO2] showed little effect on n-fatty acid chain length, but decreased the unsaturation (18:2+18:1)/18:0. Both N fertilisation and elevated [CO2] increased the quantity of leaf wax n-alkanes, whilst reducing that of n-alkanols by 20–50%, but had no simple response in fatty acid concentrations. 13C enrichment by 1–2.5‰ under N fertilisation was observed, and can be attributed to both reduced leaf conductance and increased
photosynthetic consumption of CO2. Individual n-alkyl lipids of different chain length show consistent pattern of δ13C values within each homologue, but are in general 5–8‰ more depleted in 13C than the bulk tissues. Niether nitrogen fertilisation and elevated CO2 influenced the relationship between carbon isotope discrimination of the bulk tissue and the individual lipids.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Properties of the extracellular amylase produced by the psychrotrophic bacterium, Arthrobacter psychrolactophilus, were determined for crude preparations and purified enzyme. The hydrolysis of soluble starch by concentrated crude preparations
was found to be a nonlinear function of time at 30 and 40 °C. Concentrates of supernatant fractions incubated without substrate
exhibited poor stability at 30, 40, or 50 °C, with 87% inactivation after 21 h at 30 °C, 45% inactivation after 40 min at
40 °C and 90% inactivation after 10 min at 50 °C. Proteases known to be present in crude preparations had a temperature optimum
of 50 °C, but accounted for a small fraction of thermal instability. Inactivation at 30, 40, or 50 °C was not slowed by adding
20 mg/ml bovine serum albumin or protease inhibitor cocktail to the preparations or the assays to protect against proteases.
Purified amylase preparations were almost as thermally sensitive in the absence of substrate as crude preparations. The temperature
optimum of the amylase in short incubations with Sigma Infinity Amylase Reagent was about 50 °C, and the amylase required
Ca+2 for activity. The optimal pH for activity was 5.0–9.0 on soluble starch (30 °C), and the amylase exhibited a K
m with 4-nitrophenyl-α-D-maltoheptaoside-4,6-O-ethylidene of 120 μM at 22 °C. The amylase in crude concentrates initially hydrolyzed raw starch at 30 °C at about the same
rate as an equal number of units of barley α-amylase, but lost most of its activity after only a few hours. 相似文献
15.
Dr. Erich Kessler 《Plant Systematics and Evolution》1985,151(1-2):67-71
The upper limit of temperature for growth is a species-specific character in the genusChlorella. The limits of 14Chlorella species range from 26–30°C (C. saccharophila) to 38–42°C (C. sorokiniana), withC. fusca var.vacuolata (34°C) andC. kessleri (34–36°C) assuming an intermediate position. Thus, there is no wide gap in the temperature limits between the normal (“low-temperature”)
species ofChlorella and the “high-temperature” species,C. sorokiniana. 相似文献
16.
Naoya Kitao Daisuke Fukui Masaaki Hashimoto Peter G. Osborne 《International journal of biometeorology》2009,53(2):159-165
The raccoon dog, Nyctereutes procyonoides, is a canid with a passive overwintering strategy in northern Europe. However, the behaviour and physiology of the Japanese
subspecies, N. p. albus, which has fewer chromosomes than the other subspecies, remain unknown. We measured body temperature, body composition and
blood biochemistry of wild free-ranging and fasted enclosure-housed N. p. albus during boreal winter in Hokkaido, Japan. Body temperature of N. p. albus decreased from 38°C in autumn to 35.9–36.7°C while maintaining a circadian rhythm in late February (n = 3). A transient 18–36% decrease in resting heart rate occurred when body temperature was low (n = 2). Despite a 33–45% decrease in body weight due to winter fasting, circulating glucose, total protein and triglyceride
levels were maintained (n = 4). Serum urea nitrogen dropped by 43–45% from autumn to spring, suggesting protein conservation during fasting. The overwintering
survival strategy of N. p. albus in central Hokkaido is based upon large changes in seasonal activity patterns, winter denning and communal housing without
the large decrease in body temperature that is characteristic of subarctic animals exhibiting hibernation or torpor.
Naoya Kitao, Daisuke Fukui and Peter G. Osborne contributed equally to this work 相似文献
17.
Mao-hong Zhou Jian-she Ma Jun Li Hai-ren Ye Ke-xin Huang Xiao-wei Zhao 《Biotechnology and Bioprocess Engineering》2008,13(5):545-551
A bacterial strain able to produce κ-carrageenase, designated WZUC10, was isolated from a live specimen of the red alga Plocamium telfainae collected in the East China Sea. The phylogenetic evidence and phenotypic features indicate that this strain belongs to the
genus Pseudoalteromonas. WZUC10 requires NaCl for growth and κ-carrageenan to induce κ-carrageenase synthesis; galactose and lactose do not induce
it. The optimal growth temperature is 23∼27°C. The secreted enzyme, which has a molecular mass of 45 kDa, breaks down κ-carrageenan
into κ-neocarratetraose sulfate and larger oligosaccharides with a repeating β-D-Galp4S-(1→4)-α-D-AnGalp structure, but cannot degrade κ-neocarratetraose sulfate or κ-neocarrahexaose sulfate into κ-neocarrabiose sulfate. The enzyme
retains 90% of its activity after 2 h at 40°C and is completely inactivated after 7.5 min at 70°C. The enzyme’s optimal temperature
is 30°C and its optimal pH is 7.5. The enzyme-catalyzed reaction follows Michaelis-Menten kinetics, with the Michaelis constant
(K
m) and the turnover number (k) being 0.015 mM and 125 s−1, respectively. WZUC10 produces 50 U/mL κ-carrageenase after cultivation at 25°C for 35 h on a medium containing 80 g/L glucose,
5 g/L corn steep liquor, 3 g/L κ-carrageenan, and 15 g/L NaCl. κ-Neocarratetraose sulfate was prepared simply with precipitation
by ethanol:water (5:1, v/v). 相似文献
18.
Biochemical characterisation of the esterase activities of wine lactic acid bacteria 总被引:1,自引:0,他引:1
Esters are an important group of volatile compounds that can contribute to wine flavour. Wine lactic acid bacteria (LAB) have
been shown to produce esterases capable of hydrolysing ester substrates. This study aims to characterise the esterase activities
of nine LAB strains under important wine conditions, namely, acidic conditions, low temperature (to 10°C) and in the presence
of ethanol (2–18% v/v). Esterase substrate specificity was also examined using seven different ester substrates. The bacteria
were generally found to have a broad pH activity range, with the majority of strains showing maximum activity close to pH 6.0.
Exceptions included an Oenococcus oeni strain that retained most activity even down to a pH of 4.0. Most strains exhibited highest activity across the range 30–40°C.
Increasing ethanol concentration stimulated activity in some of the strains. In particular, O. oeni showed an increase in activity up to a maximum ethanol concentration of around 16%. Generally, strains were found to have
greater activity towards short-chained esters (C2–C8) compared to long-chained esters (C10–C18). Even though the optimal physicochemical
conditions for enzyme activity differed from those found in wine, these findings are of potential importance to oenology because
significant activities remained under wine-like conditions. 相似文献
19.
Taoka Y Nagano N Okita Y Izumida H Sugimoto S Hayashi M 《Marine biotechnology (New York, N.Y.)》2009,11(3):368-374
The growth, lipid content, and fatty acid composition of Aurantiochytrium sp. strain mh0186 at different temperatures were investigated. Strain mh0186 grew well at 15–30°C, but weakly at 10°C. The
biomass at 15–30°C was significantly higher than at 10 and 35°C, and the total lipid at 15–35°C was significantly higher than
that at 10°C. The amount of DHA in the total fatty acid was highest at 10°C and decreased in response to temperature increase.
The content of DHA (mg/g-dry cell weight) at 15–30°C were significantly higher than those at 35°C and those at 15–25°C were
significantly higher than those at 10 and 35°C. The DHA yield at 15–35°C was significantly higher than those at 10 and 35°C.
Unsaturation of fatty acid was regulated by temperature and was enhanced in response to temperature decrease. The ratio of
DHA to DPA varied at different temperatures. 相似文献
20.
Yuan YJ Lu ZX Huang LJ Li Y Lu FX Bie XM Teng YQ Lin Q 《Journal of industrial microbiology & biotechnology》2007,34(8):567-570
Ochrobactrum intermedium DN2 was used to degrade nicotine in tobacco waste extracts. The optimal temperature and pH of nicotine degradation by strain
DN2 was 30–37 °C and 7.0, respectively. Under these optimal conditions, the average degradation rate of nicotine in a 30L
fed-batch culture was 140.5 mg l−1 h−1. The results of this study indicate that strain DN2 may be useful for reducing the nicotine content of reconstituted tobacco. 相似文献