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1.
V. N. Khmelenina V. G. Sakharovskii A. S. Reshetnikov Yu. A. Trotsenko 《Microbiology》2000,69(4):381-386
The1H-NMR analysis of methanol extracts of halophilic and halotolerant alkaliphilic methanotrophs isolated from the soda lakes
of Southern Transbaikal and Tuva showed that bacterial cells grown at an optimum salinity accumulated mainly sucrose and 5-oxo-1-proline,
whereas cells adapted to 0.5–1.0 M NaCl additionally synthesized ectoine. A more detailed study showed that nitrogen deficiency
in the growth medium ofMethylobacter alcaliphilus 20Z decreased the synthesis of nitrogen-contaihing osmoprotectants, ectoine and 5-oxo-1-proline.M. alcaliphilus 20Z cells exhibited activities of UDP-glucose pyrophosphorylase and sucrose-phosphate synthase involved in sucrose synthesis.
Glutamine synthetase in vitro did not require NH
4
+
ions, which implies that this enzyme is involved in 5-oxo-1-proline synthesis. Cells grown at high salinity exhibited elevated
levels of aspartate kinase, aspartate-semialdehyde dehydrogenase, and ectoine synthase. This suggests that ectoine is synthesized
via aspartate and aspartate-semialdehyde, i.e., via the route earlier established for extremely halophilic bacteria. 相似文献
2.
Yi-Guang Chen Shu-Kun Tang Yu-Qin Zhang Zhu-Xiang Liu Qi-Hui Chen Jian-Wu He Xiao-Long Cui Wen-Jun Li 《Extremophiles : life under extreme conditions》2010,14(4):397-402
A novel moderately halophilic, alkaliphilic, non-motile, non-sporulating, catalase-positive, oxidase-negative, aerobic, coccus-shaped,
Gram-positive bacterium, designated strain JSM 071043T, was isolated from a subterranean brine sample collected from a salt mine in Hunan Province, China. Growth occurred with
0.5–20% (w/v) NaCl (optimum 5–10%) at pH 6.5–10.5 (optimum pH 8.5) and at 10–40°C (optimum 25–30°C). Good growth also occurred
in the presence of 0.5–20% (w/v) KCl (optimum 5–8%) or 0.5–25% (w/v) MgCl2·6H2O (optimum 5–10%). The peptidoglycan type was A4α (l-Lys–l-Ala–l-Glu) and major cell-wall sugars were tyvelose and mannose. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. Strain JSM 071043T contained MK-9 and MK-8 as the predominant menaquinones and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol
as the major polar lipids. The DNA G + C content was 67.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed
that strain JSM 071043T was a member of the suborder Micrococcineae, and was most closely related to Zhihengliuella halotolerans YIM 70185T (sequence similarity 98.9%) and Zhihengliuella alba YIM 90734T (98.2%), and the three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis,
DNA–DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 071043T represents a novel species of the genus Zhihengliuella, for which the name Z. salsuginis sp. nov. is proposed. The type strain is JSM 071043T (= DSM 21149T = KCTC 19466T). 相似文献
3.
Various strains of coryneform bacteria, Micrococcaceae and commercial starters of Lactococcus lactis and Leuconostoc were compared for their aptitude to form S-methyl thioesters. Resting cells were incubated with methanethiol alone at pH 7 and in conjunction with a mixture of straight,
branched and hydroxy short-chain fatty acids up to C6 at pH 7 and 5. Results showed that all the strains synthesized at least S-methyl thioacetate, with strains that were low and high producers in each group. This is the only thioester formed in small
amount by Leuconostoc. Brevibacterium linens (six strains) and Micrococcaceae (five strains) were able to form branched-chain thioesters especially from their intracellular
fatty acids at neutral pH, and straight-chain thioesters mostly from exogenous fatty acids at acid pH. Coryneform bacteria
other than B. linens (four strains) and L. lactis (four starters) synthesized thioesters up to S-methyl thiobutyrate from endogenous or exogenous fatty acids but not branched-chain ones, except for one starter which formed
a very little thioisovalerate. Some particular effects of pH and added fatty acids revealed differences between species or
strains in their specific enzymatic systems.
Received: 7 April 1997 / Received revision: 5 June 1997 / Accepted: 7 June 1997 相似文献
4.
Flagella-based motility of extremely alkaliphilic Bacillus species is completely dependent upon Na+. Little motility is observed at pH values < ∼8.0. Here we examine the number of flagella/cell as a function of growth pH
in the facultative alkaliphile Bacillus pseudofirmus OF4 and a derivative selected for increased motility on soft agar plates. Flagella were produced by both strains during growth
in a pH range from 7.5 to 10.3. The number of flagella/cell and flagellin levels of cells were not strongly dependent on growth
pH over this range in either strain although both of these parameters were higher in the up-motile strain. Assays of the swimming
speed indicated no motility at pH < 8 with 10 mM Na+, but significant motility at pH 7 at much higher Na+ concentrations. At pH 8–10, the swimming speed increased with the increase of Na+ concentration up to 230 mM, with fastest swimming at pH 10. Motility of the up-motile strain was greatly increased relative
to wild-type on soft agar at alkaline pH but not in liquid except when polyvinylpyrrolidone was added to increase viscosity.
The up-motile phenotype, with increased flagella/cell may support bundle formation that particularly enhances motility under
a subset of conditions with specific challenges. 相似文献
5.
Perrig D Boiero ML Masciarelli OA Penna C Ruiz OA Cassán FD Luna MV 《Applied microbiology and biotechnology》2007,75(5):1143-1150
We evaluated phytohormone and polyamine biosynthesis, siderophore production, and phosphate solubilization in two strains
(Cd and Az39) of Azospirillum brasilense used for inoculant formulation in Argentina during the last 20 years. Siderophore production and phosphate solubilization
were evaluated in a chemically defined medium, with negative results. Indole 3-acetic acid (IAA), gibberellic acid (GA3), and abscisic acid (ABA) production were analyzed by gas chromatography-mass spectrometry. Ethylene, polyamine, and zeatin
(Z) biosynthesis were determined by gas chromatography-flame ionization detector and high performance liquid chromatography
(HPLC-fluorescence and -UV), respectively. Phytohormones IAA, Z, GA3, ABA, ethylene, and growth regulators putrescine, spermine, spermidine, and cadaverine (CAD) were found in culture supernatant
of both strains. IAA, Z, and GA3 were found in all two strains; however, their levels were significantly higher (p < 0.01) in Cd (10.8, 2.32, 0.66 μg ml−1). ABA biosynthesis was significantly higher (p < 0.01) in Az39 (0.077 μg ml−1). Ethylene and polyamine CAD were found in all two strains, with highest production in Cd cultured in NFb plus l-methionine (3.94 ng ml−1 h−1) and Az39 cultured in NFb plus l-lysine (36.55 ng ml−1 h−1). This is the first report on the evaluation of important bioactive molecules in strains of A. brasilense as potentially capable of direct plant growth promotion or agronomic yield increase. Az39 and Cd showed differential capability
to produce the five major phytohormones and CAD in chemically defined medium. This fact has important technological implications
for inoculant formulation as different concentrations of growth regulators are produced by different strains or culture conditions. 相似文献
6.
K. P. Hebbar R. D. Lumsden S. M. Poch J. A. Lewis 《Applied microbiology and biotechnology》1997,48(6):714-719
Conditions for optimizing spore production, especially chlamydospores, by host-specific mycoherbicidal strains of Fusarium oxysporum causing vascular wilts in coca (Erythroxylum coca) and poppy (Papaver somniferum) were studied in 2.5-1 fermentors. The fermentor dissolved oxygen and pH had significant effects on the growth characteristics
of F. oxysporum strains. The effect of the fungal strain, however was not significant for most of the variables studied except for chlamydospore
formation. After 14 days of fermentation, the spore types produced were microconidia and chlamydospores, with very little
production of macroconidia. While the total viable counts were significantly higher under high than under low dissolved O2, the chlamydospore counts were significantly higher under low than under high dissolved O2. The percentage of chlamydospores obtained, as a proportion of total viable was significantly higher when the fermentor pH
was increased, than when it was not. Scaling-up the liquid fermentation to 20 l, yielded log10
c = 6.8 (where c = chlamydospores ml−1) after 14 days' fermentation, with biomass viable counts of log10
v∼8.0 (where v = viable counts g−1 air-dried biomass). A single-step liquid fermentation reported in this study increased chlamydospore yields and reduced the
time required for their production with techniques currently available from 5 weeks to less than 2 weeks.
Received: 24 April 1997 / Received revision: 6 August 1997 / Accepted: 29 August 1997 相似文献
7.
The growth performance of malolactic fermenting bacteria Oenococcus oeni NCIMB 11648 and Lactobacillus brevis X2 was assessed in continuous culture. O. oeni grew at a dilution rate range of 0.007 to 0.052 h−1 in a mixture of 5:6 (g l−1) of glucose/fructose at an optimal pH of 4.5, and L. brevis X2 grew at 0.010 to 0.089 h−1 in 10 g l−1 glucose at an optimal pH of 5.5 in a simple and safe medium. The cell dry weight, substrate uptake and product formation
were monitored, as well as growth kinetics, yield parameters and fermentation balances were also evaluated under pH control
conditions. A comparison of growth characteristics of two strains was made, and this showed significantly different performance.
O. oeni has lower maximum specific growth rate (μmax=0.073 h−1), lower maximum cell productivity (Q
x
max=17.6 mg cell l−1 h−1), lower maximum biomass yield (Y
x/s
max=7.93 g cell mol−1 sugar) and higher maintenance coefficient (m
s=0.45 mmol−1 sugar g−1 cell h−1) as compared with L. brevis X2 (μmax=0.110 h−1; Q
x
max=93.2 g−1 cell mol−1 glucose; Y
x/s
max=22.3 g cell mol−1 glucose; m
s=0.21 mmol−1 glucose g−1 cell h−1). These data suggest a possible more productive strategy for their combined use in maturation of cider and wine. 相似文献
8.
H. Matsusaki N. Endo K. Sonomoto A. Ishizaki 《Applied microbiology and biotechnology》1996,45(1-2):36-40
The influence of several parameters on the fermentative production of nisin Z by Lactococcus lactis IO-1 was studied. Considerable attention has been focused on the relationship between the primary metabolite production of
bacteriocin and lactate and cell growth, which has so far not been clarified in detail. Production of nisin Z was optimal
at 30°C and in the pH range 5.0–5.5. The addition of Ca2+ to the medium showed a stimulating effect on the production of nisin Z. A maximum activity of 3150 IU/ml was obtained during
pH-controlled batch fermentation in the medium supplemented with 0.1 M CaCl2. It was about three times higher than that obtained under the optimal conditions for cell growth and lactic acid production.
Received: 12 July 1995/Received revision: 11 September 1995/Accepted: 4 October 1995 相似文献
9.
M. V. Gonchar L. B. Kostryk A. A. Sibirny 《Applied microbiology and biotechnology》1997,48(4):454-458
Mutant strains of the methylotrophic yeast Hansenula polymorpha defective in catalase (cat) and in glucose repression of alcohol oxidase synthesis (gcr1) have been isolated following multiple UV mutagenesis steps. One representative gcr1 cat mutant C-105 grows during batch cultivation in a glucose/methanol medium. However, growth is preceded by a prolonged lag
period. C-105 and other gcr1 cat mutants do not grow on methanol medium without an alternative carbon source. A large collection of second-site suppressor
catalase-defective (scd) revertants were isolated with restored ability for methylotrophic growth (Mth+) in the absence of catalase activity. These Mth+
gcr1 cat scd strains utilize methanol as a sole source of carbon and energy, although biomass yields are reduced relative to the wild-type
strain. In contrast to the parental C-105 strain, H2O2 does not accumulate in the methanol medium of the revertants. We show that restoration of methylotrophic growth in the suppressor
strains is strongly correlated with increased levels of the alternative H2O2-destroying enzyme, cytochrome c peroxidase. Cytochrome c peroxidase from cell-free extracts of one of the scd revertants has been purified to homogeneity and crystallized.
Received: 9 December 1996 / Received revision: 5 May 1997 / Accepted: 25 May 1997 相似文献
10.
Marina Kaluzhnaya Valentina Khmelenina Bulat Eshinimaev Natalia Suzina Dimitry Nikitin Alexander Solonin Ju-Ling Lin Ian McDonald Colin Murrell Yuri Trotsenko 《Systematic and applied microbiology》2001,24(2)
Five strains of obligate methanotrophic bacteria (4G, 5G, 6G, 7G and 5B) isolated from bottom sediments of Southeastern Transbaikal soda lakes (pH 9.5–10.5) are taxonomically described. These bacteria are aerobic, Gram-negative monotrichous rods having tightly packed cup-shaped structures on the outer cell wall surface (S-layers) and Type I intracytoplasmic membranes. All the isolates possess particulate methane monooxygenase (pMMO) and one strain (5G) also contains soluble methane monooxygenase (sMMO). They assimilate methane and methanol via the ribulose monophosphate pathway (RuMP). The isolates are alkalitolerant or facultatively alkaliphilic, able to grow at pH 10.5–11.0 and optimally at pH 8.5–9.5. These organisms are obligately dependent on the presence of sodium ions in the growth medium and tolerate up to 0.9–1.4 M NaCl or 1 M NaHCO3. Although being mesophilic, all the isolates are resistant to heating (80 °C, 20 min), freezing and drying. Their cellular fatty acids profiles primarily consist of C16:1. The major phospholipids are phosphatidylethanolamine and phosphatidylglycerol. The main quinone is Q-8. The DNA G+C content ranges from 49.2–51.5 mol%. Comparative 16S rDNA sequencing showed that the newly isolated methanotrophs are related to membres of the Methylomicrobium genus. However, they differ from the known members of this genus by DNA-DNA relatedness. Based on pheno- and genotypic characteristics, we propose a new species of the genus Methylomicrobium - Methylomicrobium buryatense sp. nov. 相似文献
11.
Laura Pinilla Rodrigo Torres Claudia Ortiz 《World journal of microbiology & biotechnology》2011,27(11):2521-2528
Two wild strains of Zymomonas mobilis were isolated (named as ML1 and ML2) from sugar cane molasses obtained from different farms of Santander, Colombia. Initially,
selection of the best ethanol-producer strains was carried out using ethanol production parameters obtained with a commercial
strain Z. mobilis DSM 3580. Three isolated strains were cultivated in a culture medium containing yeast extract, peptone, glucose and salts,
at pH 6 and 32°C with stirring rate of 65 rpm during 62 h. The best results of ethanol production were obtained with the native
strain ML1, reaching a maximum ethanol concentration of 79.78 g l−1. ML1 and ML2 strains were identified as Z.
mobilis, according to the morphology, biochemical tests and molecular characterization by PCR of specific DNA sequences from Z. mobilis. Subsequently, the effect of different nitrogen sources on production of ethanol was evaluated. The best results were obtained
using urea at a 0.73 g/l. In this case, maximum concentration of ethanol was 83.81 g l−1, with kinetic parameters of yield of ethanol on biomass (YP/X) = 69.01(g g−1), maximum volumetric productivity of ethanol (Qpmax) = 2.28 (g l−1 h−1), specific productivity of ethanol (qP) = 3.54 (h−1) and specific growth rate (μ) = 0.12 h−1. Finally, we studied the effect of different culture conditions (pH, temperature, stirring, C/N ratio) with a Placket-Burman′s
experimental design. This optimization indicated that the most significant variables were temperature and stirring. In the
best culture conditions a significant increase in all variables of response was achieved, reaching a maximum ethanol concentration
of 93.55 g l−1. 相似文献
12.
Yi-Guang Chen Jun Chen Qi-Hui Chen Shu-Kun Tang Yu-Qin Zhang Jian-Wu He Wen-Jun Li Yan-Qi Liu 《Antonie van Leeuwenhoek》2010,98(3):395-401
A novel Gram-stain-positive, slightly halophilic, facultatively alkaliphilic, non-motile, non-sporulating, catalase-positive,
oxidase-negative, aerobic bacterium, designated strain JSM 070026T, was isolated from non-saline forest soil in China. Growth occurred with 0–20% (w/v) NaCl (optimum, 2–4%) and at pH 6.0–10.5
(optimum, pH 8.0) and 5–40°C (optimum, 30°C). Good growth also occurred in the presence of 0–28% (w/v) KCl (optimum, 2–5%)
or 0–25% (w/v) MgCl2·6H2O (optimum, 1–4%). The peptidoglycan type was A4α (l-Lys–Gly–l-Glu). Cell-wall sugars contained mannose and xylose. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. Strain
JSM 070026T contained menaquinone 8 as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol
as the major polar lipids. The DNA G + C content of strain JSM 070026T was 56.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 070026T was a member of the suborder Micrococcineae and most closely related to Yaniella flava YIM 70178T (sequence similarity 99.4%) and Yaniella halotolerans YIM 70085T (97.9%). The three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA–DNA
relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 070026T represents a novel species of the genus Yaniella, for which the name Yaniella soli sp. nov. is proposed. The type strain is JSM 070026T (=DSM 22211T = KCTC 13527T). 相似文献
13.
A dextranase (EC 3.2.1.11) was purified and characterized from the IP-29 strain of Sporothrix schenckii, a dimorphic pathogenic fungus. Growing cells secreted the enzyme into a standard culture medium (20 °C) that supports the
mycelial phase. Soluble bacterial dextrans substituted for glucose as substrate with a small decrease in cellular yield but
a tenfold increase in the production of dextranase. This enzyme is a monomeric protein with a molecular mass of 79 kDa, a
pH optimum of 5.0, and an action pattern against a soluble 170-kDa bacterial dextran that leads to a final mixture of glucose
(38%), isomaltose (38%), and branched oligosaccharides (24%). In the presence of 200 mM sodium acetate buffer (pH 5.0), the
K
m for soluble dextran was 0.067 ± 0.003% (w/v). Salts of Hg2+, (UO2)2+, Pb2+, Cu2+, and Zn2+ inhibited by affecting both V
max and K
m. The enzyme was most stable between pH values of 4.50 and 4.75, where the half-life at 55 °C was 18 min and the energy of
activation for heat denaturation was 99 kcal/mol. S. schenckii dextranase catalyzed the degradation of cross-linked dextran chains in Sephadex G-50 to G-200, and the latter was a good
substrate for cell growth at 20 °C. Highly cross-linked grades (i.e., G-10 and G-25) were refractory to hydrolysis. Most strains
of S. schenckii from Europe and North America tested positive for dextranase when grown at 20 °C. All of these isolates grew on glucose at
35 °C, a condition that is typically associated with the yeast phase, but they did not express dextranase and were incapable
of using dextran as a carbon source at the higher temperature.
Received: 29 December 1997 / Accepted: 4 March 1998 相似文献
14.
A novel facultatively alkaliphilic bacterium that grows on a chemically defined medium containing n-alkanes as the sole carbon source was isolated from soil. The isolate was obligately aerobic, non-motile, gram-positive,
and formed metachromatic granules. It was not acidfast and did not form endospores. The cell wall contained meso-diaminopimelic acid, arabinose, and galactose; the glycan moiety of the cell wall contained acetyl residues. The bacterium
was catalase-positive, oxidasenegative, and the G+C content of DNA was 70.8 mol%. According to these tests, the isolate was
assigned to the genus Corynebacterium. The bacterium grew well between pH 6.2 to 10.2 and the doubling time in this pH range was 4–6 h. For the growth of the isolate,
added Na+ in the culture medium stimulated growth, but was not indispensable at both pH 7.2 and pH 10.2. In addition to hydrocarbons,
the isolate was able to grow on a chemically defined medium containing acetate, glucose, or fructose as the sole carbon source.
Analysis of reduced minus oxidized difference spectra of whole cells showed that the bacterium only possessed less than one tenth the amount of total
cytochromes as compared with Bacillus alcalophilus. The above results sugest that the bacterium has characteristics different than those of the alkaliphilic Bacillus previously described. 相似文献
15.
Yoshihiro Hakamada Kenzo Koike Tadashi Yoshimatsu Hajime Mori Tohru Kobayashi Susumu Ito 《Extremophiles : life under extreme conditions》1997,1(3):151-156
Thermostable alkaline cellulase (endo-1,4-β-glucanase, EC 3.2.1.4) activity was detected in the culture medium of a strictly
alkaliphilic strain of Bacillus, designated KSM-S237. This novel enzyme was purified to homogeneity by a two-step column-chromatographic procedure with high
yield. The N-terminal amino acid sequence of the purified enzyme was Glu-Gly-Asn-Thr-Arg-Glu-Asp-Asn-Phe-Lys-His-Leu-Leu-Gly-Asn-Asp-Asn-Val-Lys-Arg.
The enzyme had a molecular mass of approximately 86 kDa and an isoelectric point of pH 3.8. The enzyme had a pH optimum of
8.6–9.0 and displayed maximum activity at 45°C. The alkaline enzyme was stable up to 50°C and more than 30% of the original
activity was detectable after heating at 100°C and at pH 9.0 for 10 min. The enzyme hydrolyzed carboxymethylcellulose, lichenan
(β-1,3;1,4-linkage), and p-nitrophenyl derivatives of cellotriose and cellotetraose. Crystalline forms of cellulose (Avicel and filter paper), H3PO4-swollen cellulose, NaOH-swollen cellulose, curdlan (β-1,3-linkage), laminarin (β-1,3;1,6-linkage), and xylan were barely
hydrolyzed at all.
Received: April 28, 1997 / Accepted: May 24, 1997 相似文献
16.
Abstract
In the absence of inhibitory concentrations of copper, the photoautotrophic growth of Chlorella vulgaris INETI58C at 27°C exhibited a higher specific growth rate and reached a higher maximal concentration of biomass, under irradiance
of 150 W m−2, compared with 100 W m−2. However, when the mineral growth medium was supplemented with CuSO4 (range 40–80 μM), algal growth was significantly affected at the higher light intensity. In the presence of Cu2+, the increase in dry biomass was uncoupled from the increase in cell concentration since more than 16 autospores gathered
together, inside the enlarged mother cell, suggesting that copper arrested the normal bursting of the mother cell wall. At
the higher irradiance, growth medium supplementation with 80 μM of CuSO4 led to bleaching of photosynthetic pigments. No growth was observed, while, under the lower irradiance, growth was only slightly
inhibited. Results clearly showed that copper toxicity to growth of C. vulgaris was strongly influenced by light intensity. Higher light intensity elicits lethal or sublethal Cu2+ damage at concentrations lower than the threshold level for damage at lower light intensities. Cu2+ may elicit lethal or sublethal light damage at irradiances lower than the threshold level for unpolluted aquatic systems.
Received: 17 January 1997; Accepted 15 April 1997 相似文献
17.
In this work, a 22 factorial design was employed combining with response surface methodology (RSM) to optimize the medium compositions for the
production of alkaline β-mannanase by alkaliphilic Bacillus sp. N16-5 isolated previously from sediment of Wudunur Soda Lake in Inner Mongolia, China. The central composite design (CCD)
used for the analysis of treatment combinations showed that a second-order polynomial regression model was in good agreement
with experimental results, with R
2 = 0.9829 (P < 0.05). The maximum activity was obtained at NaCl concentration (84.4 g l−1) and sodium glutamate (3.11 g l−1) and a high medium pH around 10.0. Under such conditions, the activity of alkaline β-mannanase achieved 310.1 U/ml in the
scale of 5-l fermenter, which was increased nearly twice compared with the original. Through optimization, the substrates
shifted from the expensive substrates, such as locust bean gum and peptone, to the inexpensive ones such as konjac powder,
soymeal, and sodium glutamate. The experiment results also suggested that the environmental conditions of high salinity and
high alkalinity, as well as the inducer substrates, play very important roles in the production of the alkaline β-mannanase
by alkaliphilic Bacillus sp. N16-5. 相似文献
18.
Factors affecting the growth of Fusarium proliferatum and the production of fumonisin B1: oxygen and pH 总被引:1,自引:0,他引:1
S E Keller T M Sullivan S Chirtel 《Journal of industrial microbiology & biotechnology》1997,19(4):305-309
Fumonisins are mycotoxins produced primarily by Fusarium moniliforme and Fusarium proliferatum in corn. In liquid culture, production of fumonisin B1 (FB1), the most common moiety of the family of fumonisins, can be obtained using a defined medium that is nitrogen-limited. Under
nitrogen-limited conditions both growth and the production of FB1 were greatly influenced by pH and aeration. At pH above 5.0, F. proliferatum grew normally but produced little FB1 (<100 μg m−1). At pH below 5.0, there was less growth but substantially more FB1. Below a pH of 2.5, both growth and metabolism were slower with very little FB1 produced. When the optimal pH range of between 3.0 and 4.0 under well-aerated conditions was used, both growth and FB1 production were high. However, under oxygen-limited conditions, less growth occurred, glucose consumption was increased,
and no FB1 was produced.
Received 16 May 1997/ Accepted in revised form 03 September 1997 相似文献
19.
Gassan Hodaifa Ma. Eugenia Martínez Sebastián Sánchez 《Biotechnology and Bioprocess Engineering》2009,14(6):854-860
Olive-mill wastewater (OMW), an agro-industrial by-product from olive-oil milling (with the three-phase extraction method),
was used experimentally as 5% (v/v) of the medium to culture Scenedesmus obliquus CCAP 276/3A. The characterization of the wastewater indicated a nitrogen deficiency. The highest specific growth rate of
S. obliquus μm = 0.022 h−1 was found when the medium was maintained at a constant pH value of 7.0. The biomass productivity, Pb was determined by the influence of pH on the speciation of the dissolved CO2. The greatest elimination of BOD5 occurred at extreme pH values. The protein and chlorophyll contents presented a maximum value close to pH = 7.0. The highest
crude-protein content in the biomass was 25.6%. The polyunsaturated and essential fatty acids presented a clear trend to increase
with the pH, at pH 9.0, representing 26.2 and 19.4%, respectively, of the total fatty-acid content of the biomass. 相似文献
20.
Three facultatively anaerobic, Gram-positive staining, rod-shaped, non-spore forming, flagellated bacterial strains, BL-75,
BL-79T and BL-104, were isolated from chlorinated solvent-contaminated groundwater. Phylogenetic analysis based on 16S rRNA gene
sequence comparisons showed them to represent a distinct lineage within the genus Actinomyces with sequence identities in the range of <88–95.4% with previously described Actinomyces species. The strains were oxidase and catalase negative. Nitrate was not reduced. Esculin was hydrolyzed. Growth occurred
in the temperature range of 20–43°C (optimum 30–37°C) and pH range 4.5–9.0 (optimum pH 6.5). Substrates supporting growth
included various mono-, di-, and tri-saccharides. The end products of glucose fermentation were acetate, lactate, succinate
and formate. Fermentative growth was observed in the presence of near saturation concentrations of perchloroethene (PCE) and
toluene and in the presence of 1,2-dichloroethane and 1,1,2-trichloroethane at concentrations up to at least 24.4 mM and 11.2 mM,
respectively. The dominant cellular fatty acids when grown in peptone/yeast extract/glucose (PYG) medium were C18:1 ω9c, C16:0, and C14:0. The peptidoglycan was found to contain the amino acids alanine, glutamic acid, lysine, and ornithine at approximate molar
ratios of 1.7 Ala: 2.3 Glu: 1.3 Lys: 1.0 Orn. The cell wall sugars were found to include rhamnose and mannose. The polar lipids
were found to include diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phospholipid (PL), phosphoglycolipids (PGL),
and glycolipids (GL). The main respiratory quinone of strain BL-79T was MK-9(H4), with minor components MK-10(H4) and MK-8(H4). The DNA mol% G+C content of the type strain is 69.8%. On the basis of phylogenetic and phenotypic characteristics, these
strains could be differentiated from previously described species of the genus Actinomyces. Strains BL-75, BL-79T and BL-104 are designated as a novel species, for which the name Actinomyces naturae sp. nov. is proposed. This is the first Actinomyces species isolated from an environmental rather than human or animal sources. The type strain of Actinomyces naturae is BL-79T (= CCUG 56698T = NRRL B-24670T). 相似文献