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1.
An endophytic bacteriumn identified as Acinetobacter johnsonii strain 3–1 was isolated from surface-sterilized roots of Beta vulgaris. Its effect on sugar beet seedling growth was studied using pot assays and field experiments. This strain promoted beet seedling
growth following seed inoculation by seed dipping. Plant height and dry weight of beet increased by 19% and 69%, respectively,
compared with controls. Strain 3–1 exhibited the ability to increase absorption of N, P, K, and Mg elements from soil and
increase the content of vitamins B and C, and protein within beet. In addition, the strain also produced a phytohormone-auxin,
produced nearly twice as much IAA as that produced by strain 2–2, and was able to solubilize phosphates. The concentration of dissolved P in the medium was 180.5 mg L −1 after 4 days of incubation. In field experiments, strain 3–1 significantly increased the content of sucrose, fructose, and
the yield of the beet. The growth-promoting properties of Acinetobacter johnsonii strain 3–1 indicates that this promising isolate merits further investigation into its symbiosis with beet plants and its
potential application in agriculture. 相似文献
2.
Novel thermophilic and alkaliphilic bacteria for the processing of bast fibres were isolated using hemp pectin as substrate.
The strain PB94A, which showed the highest growth rate ( μ = 0.5/h) was identified as Geobacillus thermoglucosidasius (DSM 21625). The strain grew optimally at 60°C and pH 8.5. During growth on citrus pectin, the strain produced pectinolytic
lyases, which were excreted into the medium. In contrast to the commercially available pectinase Bioprep 3000 L, the enzymes
from G. thermoglucosidasius PB94A converted pectin isolated from hemp fibres. In addition to hemp pectin, the culture supernatant also degraded citrus,
sugar beet and apple pectin and polygalacturonic acid. When hemp fibres were incubated with the cell-free fermentation broth
of G. thermoglucosidasius PB94A, the fineness of the fibres increased. The strain did not produce any cellulases, which is important in order to avoid
damaging the fibres during incubation. Therefore, these bacteria or their enzymes can be used to produce fine high-quality
hemp fibres. 相似文献
3.
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 CO 2 with H 2 or formate as electron donor. Growth on formate was much slower than that on H 2. 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 B 12, 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 H 2-using methanogens from saline environments metabolized H 2 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
4.
Summary The relationship between the EUF-nutrient fractions in the soil on the one hand and the nutrient uptake of sugar beet as well
as root yield and quality (polarization, α-amino N etc.) on the other is described on the basis of results obtained over several
years in surveys conducted in farmers' fields (5000–6000 fields under sugar beet per year) and in field experiments (25–35
sites per year).
Statistically significant close correlations with the respective parameters were found for the following EUF nutrient fractions:
EUF-NO 3, EUF-P, EUF-K, EUF-Na, EUF-B and EUF-Mn.
Within five years it was possible to determine the EUF-nutrient values which are required for the production of 9 t sugar/ha.
These EUF values are the following: Ca: 65–70 mg/100 g at 20°C K: 11–15 mg/100 g at 20°C (depending on the clay content) Mg:
3–5 mg/100 g at 20°C Na: 2–3 mg/100 g at 20°C P: 1.4–1.6 mg/100 g at 20°C
For calculation of the N fertilizer requirements of sugar beet it is suggested to use the sum of the EUF-extractable N amounts.
It was found in Austria, Yugoslavia and Denmark over a period of 3 years that the EUF-N value of 1 mg/100 g soil determined
between June and September was equivalent to 40 kg N/ha. If, for example, the analysed soil contains 3 mg EUF-N/100 g, 3×40=120
kg N/ha will be available to the sugar beet crop in the following year. 相似文献
5.
Three methods of short-term storage of the blowfly Calliphora vicina strains are considered based on the experimental study of 21 strains originating from different parts of the species range.
The colony can be preserved as diapausing adults at 6° and darkness for 2–3 months or more, depending on the geographical
origin of the population. During the first five days of adult life the flies should be kept at 12° and short day on a sugar
diet, after which they should be transferred into a refrigerator. During artificial hibernation the flies also require periodic
sugar feeding every 20 days (3–4 h at 20°C) to maintain their vital functions. The combination of temperatures of 20–23°C
and a protein diet terminates reproductive diapause, and oviposition starts in 10–17 days. The fly strain may be preserved
as reproductive females at 6°C and darkness with sugar feeding. Flies also require periodic sugar feeding at 20°C (3–4 hours).
In this case the flies start laying eggs 2–3 days after being transferred to 20–23°C. The preservation of diapausing larvae
is a more reliable method of prolonged strain storage. In this case the flies of maternal generation are maintained at 20–23°C
on sugar and protein diet. The egg rafts laid during 5–6 hours are then transferred into 12°C and short day until hatchment.
The hatched larvae should be immediately placed into a refrigerator (2–3 or 5–6°C), where they feed during 1–1.5 months and
enter diapause. For strain restoration, the diapausing larvae should be transferred into 20–25°C, where they pupariate in
3–5 days and the flies emerge in nearly 10 days. 相似文献
6.
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
7.
An alkalophilic Streptomyces sp. RCK-SC, which produced a thermostable alkaline pectinase, was isolated from soil samples. Pectinase production at 45
°C in shaking conditions (200 rev min −1) was optimal (76,000 IU l −1) when a combination of glucose (0.25% w/v) and citrus pectin (0.25% w/v) was added along with urea (0.25% w/v) in the basal
medium devoid of yeast extract and peptone. All the tested amino acids and vitamins greatly induced pectinase production and
increased the specific productivity of pectinase up to 550%. In an immobilized cell system containing polyurethane foam (PUF),
the pectinase production was enhanced by 32% (101,000 IU l −1) compared to shake flask cultures. In solid-state cultivation (SSC) conditions, using wheat bran as solid substrate, pectinase
yield of 4857 IU g −1 dry substrate was obtained at substrate-to-moisture ratio of 1:5 after 72 h of incubation. The partially purified pectinase
was optimally active at 60 °C and retained 80% of its activity at 50 °C after 2 h of incubation. The half life of pectinase
was 3 h at 70 °C. Pectinase was stable at alkaline pH ranging from 6.0 to 9.0 for more than 8 h at room temperature retaining
more than 50% of its activity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
BackgroundTobacco stalk (TS), a major agricultural waste abundant in pectin, has resulted in concerns about the need for its reuse. The nicotine in TS is considered a chemical that is to\xic and hazardous to the environment. ResultsIn this study, Bacillus tequilensis CAS-MEI-2-33 was isolated from cigar wrappers to produce alkaline pectinase using TS. Subsequently, the medium and fermentation conditions for the production of pectinase by B. tequilensis CAS-MEI-2-33 were optimized. The optimal fermentation period, pH of the initial fermentation medium, concentration of TS, and inoculum amount for B. tequilensis CAS-MEI-2-33 were 40 h, 40 g/L, 7.0, and 3%, respectively. Under optimal conditions, the pectinase activity was 1370 U/mL. Then, the enzymatic properties, such as the optimum pH, reaction temperature, temperature stability, and effects of metal ions, were studied. The optimal pH was determined to be 10.0, indicating that the enzyme was an alkaline pectinase. The optimal temperature was 40 °C, and pectinase activity was stable at 40 °C. The Ag+ metal ions were shown to remarkably promote enzyme activity. The pectinase was partly purified by ammonium sulfate precipitation, ion exchange chromatography, and Sephacryl S-100 chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and LC-MS/MS analyses were utilized to analyze the pectinase. ConclusionsThis study provided a new alkaline pectinase candidate and a new strategy for the use of TS. 相似文献
9.
A very high level of alkalophilic and thermostable pectinase and xylanase has been produced from newly isolated strains of
Bacillus subtilis and Bacillus pumilus respectively. Enzyme production for pectinase was carried out under SSF using combinations of cheap agricultural residues
while xylanase was produced under submerged fermentation using wheat bran as substrate to minimize the cost of production
of these enzymes Among the various substrates tested, the highest yield of pectinase production was observed by using combination
of WB + CW (6592 U/g of dry substrate) supplemented with 4% yeast extract when incubated at 37 °C for 72 h using deionized
water of pH 7.0 as moistening agent. The biobleaching effect of these cellulase free enzymes on kraft pulp was determined.
Both xylanase and pectinase showed stability over a broad range of pH from 6 to 10 and temperature from 55 to 70 °C. The bleaching
efficiency of the pectinase and xylanase on kraft pulp was maximum after 150 min at 60 °C using enzyme dosage of 5 IU/ml of
each enzyme at 10% pulp consistency with about 16% reduction in kappa number and 84% reduction in permanganate number. Enzyme
treated pulp when subjected to CDED 1D 2 steps, 25% reduction in chlorine consumption and upto 19% reduction in consumption of chlorine dioxide was observed for obtaining
the same %ISO brightness. Also an increase of 22 and 84% in whiteness and fluorescence respectively and a decrease of approximately
19% in the yellowness of the biotreated pulp were observed by pretreatment of the pulp with our enzymatic mixture. 相似文献
10.
Temperature profiles (range 20–33 °C) were obtained for growth and exopolysaccharide (EPS) biosynthesis of the microalga Botryococcus braunii strain UC 58 under photoautotrophic conditions. The maximum temperature for growth was 32 °C and the temperature dependence
of the specific growth rate was described by the Hinshelwood equation based on the Arrhenius relationship. The optimal range
of temperatures for growth and extracellular EPS synthesis (25–30 °C) concurred and production of 4.5–5 g l −1 of EPS was obtained routinely, leading to high broth viscosities. Below 23 °C EPS biosynthesis was negligible, although the
specific growth rate maintained high values. At supraoptimal temperatures EPS biosynthesis decreased, accompanying the increase
in doubling time.
The polymers formed at temperatures within the optimal range for production, when dissolved in water, produced solutions (2
gl −1) with the highest viscosity, suggesting that their molecular weight showed the highest values. The degree of polymerization
of the EPS synthesized at suboptimal and supraoptimal temperatures was significantly below the values within the optimal range. 相似文献
11.
A novel fibrinolytic enzyme (AJ) was purified from Staphylococcus sp. strain AJ screened from Korean salt-fermented Anchovy -jeot. Relative molecular weight of AJ was determined as 26 kDa by using SDS-PAGE and fibrin zymography. Based on a 2D gel, AJ
was found to consist of three active isoforms (p I 5.5–6.0) with the same N-terminal amino acid sequence. AJ exhibited optimum pH and temperature at 2.5–3.0 and 85°C, respectively.
AJ kept 85% of the initial activity after heating at 100°C for 20 min on the zymogram gel. The Michaelis constant ( K
m) and K
cat values of AJ towards α-casein were 0.38 mM and 19.73 s −1, respectively. AJ cleaved the Aα-chain of fibrinogen but did not affect the Bβ- and γ-chains, indicating that it is an α-fibrinogenase.
The fibrinolytic activity was inhibited by diisopropyl fluorophosphate, indicating AJ is a serine protease. Interestingly,
AJ was very stable at acidic condition, SDS, and heat (100°C), whereas it was easily degraded at neutral and alkaline conditions.
In particular, AJ formed an active homo-dimer in the pH range from 7.0 to 8.0. To our knowledge, a similar combination of
acid and heat stability has not yet been reported for other fibrinolytic enzymes. 相似文献
12.
A thermophilic Bacillus strain NG80-2 growing within the temperature range of 45–73°C (optimum at 65°C) was isolated from a deep subterranean oil-reservoir in northern China. The strain was able to utilize crude oil and liquid paraffin as the sole carbon sources for growth, and the growth with crude oil was accompanied by the production of an unknown emulsifying agent. Further examination showed that NG80-2 degraded and utilized only long-chain (C15–C36) n-alkanes, but not short-chain (C8–C14) n-alkanes and those longer than C40. Based on phenotypic and phylogenic analyses, NG80-2 was identified as Geobacillus thermodenitrificans. The strain NG80-2 may be potentially used for oily-waste treatment at elevated temperature, a condition which greatly accelerates the biodegradation rate, and for microbial enhancing oil recovery process.Lei Wang, Yun Tang and Shuo Wang contributed equally to this study. 相似文献
13.
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
14.
In the process of biooxidation at 39°C in a continuous mode of the gold-arsenic concentrate from the Olympiadinskoe deposit,
which was pretreated by chemical leaching with ferric ions, by a microbial association from the BIO department reactors of
the Polyus gold mining company, a bacterial culture designated as strain HT-4 was isolated. The bacterium was a spore-forming
rod 0.5–0.6 × 1.4–2.0 μm with a flagellum. The optimal temperature for growth and Fe 2+ oxidation was 55°C. The strain grew in the pH range from 1.21 to 2.10 with the optimum at pH 1.6. The organism was incapable
of lithotrophic and organotrophic growth. It grew mixotrophically by Fe 2+ oxidation in the presence of 0.02% yeast extract. The DNA G+C base content was 48.6 mol %. Based on comparative phylogenetic
analysis of 1472-bp nucleotide sequences of 16S rRNA genes, strain HT-4 was classified as Sulfobacillus thermosulfidooxidans. Analysis by pulse-field gel electrophoresis revealed a unique profile of the NotI fragments of the chromosomal DNA. These results demonstrate the strain and species diversity of sulfobacilli in microbial
associations involved in biooxidation of concentrates in different technological conditions. The strain “ S. olympiadicus S-5” dominated in the process of biooxidation of original concentrate not treated with ferric iron, while S. thermosulfidooxidans HT-4 was predominant in biooxidation of the chemically leached concentrate. 相似文献
15.
The upper limit of temperature for growth is a species-specific character in the genus Chlorella. The limits of 14 Chlorella species range from 26–30°C ( C. saccharophila) to 38–42°C ( C. sorokiniana), with C. fusca var. vacuolata (34°C) and C. kessleri (34–36°C) assuming an intermediate position. Thus, there is no wide gap in the temperature limits between the normal (“low-temperature”)
species of Chlorella and the “high-temperature” species, C. sorokiniana. 相似文献
16.
Three strains of gram-positive, motile, rod-shaped and boron (B)-tolerant bacterium were isolated from naturally B containing
soil of Hisarcik area in the Kutahya Province, Turkey. The strains, designated as T-14A, T-15Z T and T-17s, produced spherical or ellipsoidal endospores in a terminal bulging sporangium. The strains required B for the
growth and can tolerate more than 450 mM B. These also tolerated up to 7.0% (w/v) NaCl in the presence of 50 mM B in agar
medium but grew optimally without NaCl. The temperature range for growth was 16–37°C (optimal of 30°C), whereas the pH range
was 6.5–9.0 (optimal of 7.5–8.5). The DNA G + C content was 41.1–42.2 mol% and the predominant cellular fatty acid was iso-C 15:0. The major respiratory quinone system was detected as MK-7 and the diamino acid of the peptidoglycan was meso-diaminopimelic acid. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis of 16S rRNA gene sequences
data and DNA–DNA re-association values, we concluded that the three strains belong to a novel species of the genus Bacillus, the type strain of which is T-15Z T and for which we proposed the name, B. boroniphilus sp. nov. (DSM 17376 T = IAM 15287 T = ATCC BAA-1204 T). 相似文献
17.
The aim of this work was to compare the coldlability of phosphofructokinase (EC 2.7.1.11) from tubers of potato cultivars
(cvs.) known to differ in their propensity to accumulate sugars at low temperature. When stored at 4°C for six weeks, the
sugar content of tubers of Solanum tuberosum L. cv. Record doubled whereas the amount of sugar in tubers of cv. Brodick and an advanced breeding clone (13676) decreased
slightly. Tubers from each line contained four forms of phophofructokinase. Over the range 12°–16°C the temperature coefficients
of the four forms of phosphofructokinase from cvs. Record and Brodick were similar. In cv. Record the temperature coefficients
of three of the enzyme forms were significantly higher at 2°–6°C than at 12°–16°C, whereas those from cv. Brodick were unchanged.
These results are consistent with the proposal that inactivation of phosphofructokinase at low temperature results in the
accumulation of hexose phosphates leading to increased sucrose synthesis. 相似文献
18.
AbstractIn the present study, Isoptericola variabilis strain UD-6 isolated from alkaline hot spring of Unapdev, Maharashtra, India was assessed for its biobleaching activity by hydrolytic enzymes on rice straw pulp. Results of primary and secondary screening manifested that it was a multi-enzyme producer, competent to produce amylase, cellulase, mannanase, pectinase, and xylanase at 9.73, 4.11, 6.26, 8.42, and 6.61?IU?ml ?1 in fermentation conditions, respectively. Maximum activity of all enzymes was gained at thermal temperature (50–55?°C), alkaline condition (pH 8–9), under 5?mM KCl and 5?mM NaCl salt concentration. In compatibility testing, activities of all enzymes were spectacularly reduced when they utilized with chemicals of pulp bleaching. Results of rice straw pulp bleaching was effectual when pulp was initially bleached with mannanase, pectinase, and xylanase enzymes (Es) for 90?min and then with diluted chemicals (DC) for further 90?min instead of their separate use. Treatment of rice straw pulp with Es?+?DC, enhanced the release of reducing sugars, hydrophobic compounds, and phenolic compounds, whereas Kappa number was reduced. Overall, the results of the present study indicated that pre-bleaching of pulp with hydrolytic enzymes obtained from I. variabilis strain UD-6 helps to minimize chemicals used in the bleaching process and make it more sustainable for pulp and paper industries as well as for the environment. 相似文献
19.
An endoglucanase was purified to homogeneity from an alkaline culture broth of a strain isolated from␣seawater and identified
here as Bacillus agaradhaerens JAM-KU023. The molecular mass was around 38-kDa and the N-terminal 19 amino acids of the purified enzyme exhibited 100% sequence
identity to Cel5A of B. agaradhaerens DSM8721 T. The enzyme activity increased around 4-fold by the addition of 0.2–2.0 M NaCl in 0.1 M glycine–NaOH buffer (pH 9.0). KCl,
Na 2SO 4, NaBr, NaNO 3, CH 3COONa, LiCl, NH 4NO 3, and NH 4Cl also activated the enzyme up to 2- to 4-fold. The optimal pH and temperature values were pH 7–9.4 and 60 °C with 0.2 M
NaCl, but pH 6.5–7 and 50 °C without NaCl; enzyme activity increased approximately 6-fold at 60 °C with 0.2 M NaCl compared
to that at 50 °C without NaCl in 0.1 M glycine–NaOH buffer (pH 9.0). The thermostability and pH stability of the enzyme were
not affected by NaCl. The enzyme was very stable to several chemical compounds, surfactants and metal ions (except for Fe 2+ and Hg 2+ ions), regardless whether NaCl was present or not.
* The nucleotide sequence of 16S rRNA of this strain has been submitted to DDBJ, EMBL, and GenBank databases under accession
no. AB211544. 相似文献
20.
Lactobacillus delbrueckii was grown on sugarcane molasses, sugarcane juice and sugar beet juice in batch fermentation at pH 6 and at 40°C. After 72 h,
the lactic acid from 13% (w/v) sugarcane molasses (119 g total sugar l −1) and sugarcane juice (133 g total sugar l −1) was 107 g l −1 and 120 g l −1, respectively. With 10% (w/v) sugar beet juice (105 g total sugar l −1), 84 g lactic acid l −1 was produced. The optical purities of d-lactic acid from the feedstocks ranged from 97.2 to 98.3%. 相似文献
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