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1.
Production of a hypoglycemic, extracellular polysaccharide from the submerged culture of the mushroom, Phellinus linteus 总被引:15,自引:0,他引:15
Dong-Hyun Kim Byung-Keun Yang Sang-Chul Jeong Jun-Bo Park Sung-Pill Cho Surajit Das Jong-Won Yun Chi-Hyun Song 《Biotechnology letters》2001,23(7):513-517
Mycelial growth and extracellular polysaccharide production of Phellinus linteus were optimal at pH 5 and 25 °C. Maximum biomass production (14.2 g l–1) was after 15 d of cultivation, whereas, extracellular polysaccharide was maximal (3.5 g l–1) after 21 d. The hypoglycemic effect of the polysaccharide, investigated in streptozotocin-induced diabetic rats, decreased plasma glucose, total cholesterol and triacylglycerol concentrations by 49%, 32%, and 28%, respectively, and aspartate aminotransferase activity by 20%. The results indicate the potential of this polysaccharide to prevent hyperglycemia in diabetic patients. 相似文献
2.
To investigate the influence of temperature andholding time on the pyrolyzate yields of Chlorella protothecoides, the microalgal cells weresubjected to pyrolysis at 200, 300, 400, 500 and 600 °Cfor 5, 20, 60 and 120 min, separately. High oil yields above 40% dry weight cells wereobtained both at relatively low temperature (300 °C)with relatively long holding times (20–120min) and relatively high temperatures (400–500 °C)with relatively short holding times (5–20min). The maximum oil yield of 52.0% was achieved at500 °C for 5 min. The gas yield was generallyincreased with the increasing temperature and holdingtime. It could reach 63.3–76.0% at 600 °C.High pyrolytic rates of 72–87% were obtained at allexperiments except at 200 °C for 5–20 min or300 °C for 5 min. Thermogravimetric analysisindicated that the main thermal degradation of thismicroalga occurred at 200–520 °C. The resultsimply that C. protothecoides is a good candidatefor the production of renewable fuels by pyrolysis. 相似文献
3.
Kochia scoparia is one of the most common annual halophytes foundin the Great Basin. Seeds were collected from a population growing in asalt playa at Faust, Utah and were germinated at 5 temperature regimes(12 h night/12 h day, 5–15 °C, 10–20 °C, 15–25 °C,20–30 °C and 25–35 °C) and 6 salinities (0, 200, 400,600, 800 and 1000 mM NaCl) to determine optimal conditions forgermination and recovery of germination from saline conditions after beingtransferred to distilled water. Maximum germination occurred in distilledwater, and an increase in NaCl concentration progressively inhibited seedgermination. Few seeds germinated at 1000 mM NaCl. A temperatureregime of 25 °C night and 35 °C day yielded maximumgermination. Cooler temperature 5–15 °C significantly inhibited seedgermination. Rate of germination decreased with increase in salinity.Germination rate was highest at 25–35 °C and lowest at5–15 °C. Seeds were transferred from salt solutions to distilled waterafter 20 days and those from high salinities recovered quickly at warmertemperature regimes. Final recovery germination percentages in high salttreatments were high, indicating that exposure to high concentration ofNaCl did not inhibit germination permanently. 相似文献
4.
The carrageenan-producing red algaKappaphycus alvarezii (Doty) Doty was brought to Vietnam from Japan in 1993. Branch fragments of this species were cultivated in a pond, lagoon, inlet and offshore in Vietnam for the first time. The best daily growth rate (DGR) of plants grown in the lagoon area attained 9–11 % day–1 in May to June (cold season). The water temperature and salinity in this area ranged from 27.2–32.4 °C and 31.4–33.7 °C, respectively. DGR of plants grown in the inlet ranged from 7 to 9% day–1 in June. Grazing by fish has been observed to occur in this area. The DGR of plants grown in the pond ranged from 5–6% in January–July, but decreased to less than 4% day–1 in August (hot season).
K. alvarezii in Vietnam showed a carrageenan yield of 18.8–24.6% and gel strength of 1566–1712 g cm–2. These values are similar ones obtained fromK. alvarezii cultivated in the Philippines and Indonesia. 相似文献
5.
The critical swimming velocity (Ucrit) of four California stream fishes, hardhead, Mylopharodon conocephalus, hitch, Lavinia exilicauda, Sacramento pikeminnow, Ptychocheilus grandis, and Sacramento sucker, Catostomus occidentalis was measured at 10, 15, and 20°C. Hardhead, Sacramento sucker, and Sacramento pikeminnow swimming performances tended to be lowest at 10°C, higher at 15°C, and then decreased or remained constant at 20°C. Hitch swimming performance was lower at 10°C than at 20°C. There were no significant differences among species at 10 or 15°C, although pikeminnow and hitch were ca. 20% slower than hardhead or sucker. At 20°C hardhead, Sacramento sucker, and Sacramento pikeminnow had remarkably similar Ucrit but hitch were significantly (by 11%) faster. We recommend that water diversion approach velocities should not exceed 0.3ms–1 for hitch (20–30cm total length) and 0.4ms–1 for hardhead, Sacramento pikeminnow, and Sacramento sucker (20–30cm TL). 相似文献
6.
Grape skins as a natural support for yeast immobilization 总被引:1,自引:0,他引:1
A. Mallouchos P. Reppa G. Aggelis M. Kanellaki A.A. Koutinas M. Komaitis 《Biotechnology letters》2002,24(16):1331-1335
Grape skins were used to immobilize Saccharomyces cerevisiae. In repeated batch fermentations of grape by immobilized and free cells, the maximum specific rate of alcohol production on glucose decreased from 7.98 h–1 at 25 °C to 0.7 h–1 at 5 °C. The rate was approximately twice as high as that on fructose. The rates for free cells were very low. The maximum alcohol yield (0.45 g g–1) was obtained at 5 °C when the immobilized biocatalyst was used. 相似文献
7.
Purification and characterization of a high molecular mass serine carboxypeptidase from <Emphasis Type="Italic">Monascus pilosus</Emphasis> 总被引:1,自引:0,他引:1
Liu F Tachibana S Taira T Ishihara M Kato F Yasuda M 《Journal of industrial microbiology & biotechnology》2004,31(12):572-580
Two serine carboxypeptidases, MpiCP-1 and MpiCP-2, were purified to homogeneity from Monascus pilosus IFO 4480. MpiCP-1 is a homodimer with a native molecular mass of 125 kDa composed of two identical subunits of 61 kDa, while MpiCP-2 is a high mass homooligomer with a native molecular mass of 2,263 kDa composed of about 38 identical subunits of 59 kDa. This is unique among carboxypeptidases and distinguishes MpiCP-2 as the largest known carboxypeptidase. The two purified enzymes were both acidic glycoproteins. MpiCP-1 has an isoelectric point of 3.7 and a carbohydrate content of 11%, while for MpiCP-2 these values were 4.0 and 33%, respectively. The optimum pH and temperature were around 4.0 and 50°C for MpiCP-1, and 3.5 and 50°C for MpiCP-2. MpiCP-1 was stable over a broad range of pH between 2.0 and 8.0 at 37°C for 1 h, and up to 55°C for 15 min at pH 6.0, but MpiCP-2 was stable in a narrow range of pH between 5.5 and 6.5, and up to 50°C for 15 min at pH 6.0. Phenylmethylsulfonylfluoride strongly inhibited MpiCP-1 and completely inhibited MpiCP-2, suggesting that they are both serine carboxypeptidases. Of the substrates tested, benzyloxycarbonyl-l-tyrosyl-l-glutamic acid (Z-Tyr-Glu) was the best for both enzymes. The Km, Vmax, Kcat and Kcat/Km values of MpiCP-1 for Z-Tyr-Glu at pH 4.0 and 37°C were 1.33 mM, 1.49 mM min–1, 723 s–1 and 545 mM–1 s–1, and those of MpiCP-2 at pH 3.5 and 37°C were 1.55 mM, 1.54 mM min–1, 2,039 s–1 and 1,318 mM–1 s–1, respectively. 相似文献
8.
9.
Seasonal variation in the physical properties of agar and biomass of Gracilaria sp. (chorda type) from Tosa Bay,southern Japan 总被引:1,自引:1,他引:0
Plants of Gracilaria sp.(chorda type), which grow along the coast of Uranouchi Inlet in Tosa Bay, southern Japan, showed the highest biomass in the summer (26 °C to 31 °C) and spring season (15.1 °C to 24.9 °C). Maximum biomass was 6952 g m–2 in July, but gradually decreased in the autumn (30.5 °C in September to 20 °C in November) and winter (19.5 °C in December to 14.9 °C in February). Variation in yields and gel strength of the agars, were shown to depend on the time in the season. After alkali treatment (5% NaOH, 2 h) at three different temperatures (70, 80, and 90 °C), the agars showed gel strengths essentially that of commercial grade agars, with the best gel obtained at 80 °C. Maximum gel strength (1455 g cm–2 of 1.5% agar gel) occurred in winter when the biomass and agar yield were low. Minimum gel strength was in spring. Gel strength was inversely correlated with agar yield, but was positively correlated with apparent viscosity. Maximum viscosity was 40 cP. in December. Gelling temperatures, pH of 1.5% agar gel, and moisture content in agars showed little variation. 相似文献
10.
Electron spin resonance spectroscopy was used to monitor the in vivo microviscosity of the plasma membrane and lipid extracts of the salt tolerant alga, Dunaliella primolecta. The fluidity of the plasma membrane decreased as the algae were adapted to and suspended in higher sodium chloride concentrations [2–24% (w/v)]. Both biochemical modification and a physical interaction between Na+ and lipids were implicated.When the microviscosity of the plasma membrane and that of lipid extracts were determined as a function of temperature, two or three lipid phase transformations were observed. There were always transformations at 9–14° C and 39–43° C. These were interpreted as the onset and completion of the lipid phase transition of at least a major lipid component of the membrane, possibly the entire membrane. These transformation temperatures were independent of the salt concentration to which the algae were adapted or suspended. This suggests that D. primolecta exists with some of its membrane in the solid-fluid mixed lipid state. With a NaCl concentration of 8% (w/v) or greater in the growth medium, a third transformation occurred around 20–22° C. It was the result of a lipid-lipid interaction and was not related to adaptation.Abbreviations ESR
electron spin resonance spectroscopy
- 2 T
hyperfine splitting
- S
order parameter
- 5-DS or 5-doxyl-stearate
2-(3-carboxylpropyl)-4,4-dimethyl-2-tridecyl-3-oxazolidinyloxyl 相似文献
11.
A hyper-thermostable, alkaline lipase from Pseudomonas sp. with the property of thermal activation 总被引:1,自引:0,他引:1
A hyper-thermostable, alkaline lipase from a newly-isolated, mesophilic Pseudomonas sp. was optimal at pH 11 and at 90 °C. It had a half-life of more than 13 h at 90 °C. It was activated by 30% when heated at 90 °C for 2 h. The enzyme had a greater affinity for mustard oil (K
m=40 mg ml–1) than for olive oil (K
m=140 mg ml–1). 相似文献
12.
Petz M Stabentheiner A Crailsheim K 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2004,174(7):511-518
The CO2 production of individual larvae of Apis mellifera carnica, which were incubated within their cells at a natural air humidity of 60–80%, was determined by an open-flow gas analyzer in relation to larval age and ambient temperature. In larvae incubated at 34 °C the amount of CO2 produced appeared to fall only moderately from 3.89±1.57 µl mg–1 h–1 in 0.5-day-old larvae to 2.98±0.57 µl mg–1 h–1 in 3.5-day-old larvae. The decline was steeper up to an age of 5.5 days (0.95±1.15 µl mg–1 h–1). Our measurements show that the respiration and energy turnover of larvae younger than about 80 h is considerably lower (up to 35%) than expected from extrapolations of data determined in older larvae. The temperature dependency of CO2 production was determined in 3.5-day-old larvae, which were incubated at temperatures varying from 18 to 38 °C in steps of 4 °C. The larvae generated 0.48±0.03 µl mg–1 h–1 CO2 at 18 °C, and 3.97±0.50 µl mg–1 h–1 CO2 at 38 °C. The temperature-dependent respiration rate was fitted to a logistic curve. We found that the inflection point of this curve (32.5 °C) is below the normal brood nest temperature (33–36 °C). The average Q10 was 3.13, which is higher than in freshly emerged resting honeybees but similar to adult bees. This strong temperature dependency enables the bees to speed up brood development by achieving high temperatures. On the other hand, the results suggest that the strong temperature dependency forces the bees to maintain thermal homeostasis of the brood nest to avoid delayed brood development during periods of low temperature.Abbreviations m body mass - R rate of development or respiration - TI inflexion point of a logistic (sigmoid) curve - TL lethal temperature - TO temperature of optimum (maximum) developmentCommunicated by G. Heldmaier 相似文献
13.
When Lactococcus lactis strains were exposed directly to the lethal temperature of 50 C for 30 ;min, 0.1–31% of the cells survived. However, when pre-exposed to 40 °C, prior to exposure at 50 °C, 4–61% of the cells survived. A plasmid carrying a unique heat shock gene from the thermophile Streptococcus thermophilus was cloned into L. ;lactis. When the transformed cells were cultivated at 30 °C the introduction of the plasmid had no obvious effect on the growth of L. ;lactis. However, when the temperature was abruptly shifted from 30 °C to 42 °C at mid-growth phase the growth decreased by 50%. 相似文献
14.
Pichia anomala, isolated from dried flower buds of Woodfordia fruticosa, produced a high activity of an intracellular phytase, at 68 U per g dry biomass, when grown at 20 °C for 24 h in a medium containing glucose (40 g l–1) and beef extract (10 g l–1) supplemented with Fe2+ (0.15 mM). Partially purified phytase was optimally active at 60 °C and pH 4 with a half life of 7 days at 60 °C. It retained 85% of its activity at 80 °C for 15 min. The enzyme is suitable for supplementing animal feeds to improve the availability of phosphate from phytate. 相似文献
15.
A thermotolerant methylotrophicBacillus sp. (KISRI TM1A, NCIMB 40040), isolated from the Kuwaiti environment and belonging to the group II spore-forming, bacilli, could not be correlated with any knownBacillus sp. It may, therefore, be a new species. It grew at temperatures from 37° to 58°C from pH 6.5 to 9.0 and on methanol up to 40 g l–1. It grew well in a chemostat. Its biomass yield coefficient was improved by about 30% by optimization of medium and growth conditions, reaching a maximum of 0.44g g–1 at 45°C pH 6.8 to 7.0, dilution rate 0.25 h–1 with methanol at 10 g l–1. Average crude protein and amino acid content were 84% and 60%, respectively, and maximum productivity attained under laboratory conditions was 5.06 g l–1h–1. It was concluded that this strain has good potential for use in single-cell protein production. 相似文献
16.
The combined effects of water activity (aw) and temperature on mycotoxin production by Penicilium commune (cyclopiazonic acid — CPA) and Aspergillus flavus (CPA and aflatoxins — AF) were studied on maize over a 14-day period using a statistical experimental design. Analysis of variance showed a highly significant interaction (P 0.001) between these factors and mycotoxin production. The minimum aw/temperature for CPA production (2264 ng g–1
P. commune, 709 ng g–1
A. flavus) was 0.90 aw/30 °C while greatest production (7678 ng g–1
P. commune, 1876 ng g–1
A. flavus) was produced at 0.98 aw/20 °C. Least AF (411 ng g–1) was produced at 0.90 aw/20 °C and most (3096 ng g–1) at 0.98 aw/30 °C. 相似文献
17.
Microbacterium thermosphactum was grown at 5°C and 9°C in glucose-limited continuous cultures. The end products of glucose metabolism were L-lactate and ethanol, and these compounds accounted for 86–92% of the glucose utilized. With input glucose concentrations less than 3 mM Y
glu
Max
was found to be 40–43, Y
ATP
Max
20–21 and m
s 0.1–0.2. These values are almost identical to those found previously for cultures at 25°C and show that this psychrotroph grows with a very high energetic efficiency over a wide range of temperatures. With a higher (but still limiting) input glucose concentration of 5.6 mM at 9°C, cellular efficiency declined as there was a marked reduction in Y
glu. This decrease was accounted for in mathematical terms by an increase in m
s to 0.7, whilst Y
glu
Max
and Y
ATP
Max
remained high at 38 and 19 respectively. 相似文献
18.
Bacterial density and composition in association of mass cultivated rotifers (Brachionus plicatilis, SINTEF-strain) was investigated, during experimental conditions identical to the procedures used for preparing rotifers as live food for marine cold water fish larvae. These procedures include cultivation, enrichment with squid meal and acclimation to low temperature by storage of the rotifer culture at 6 °C. Large variations were observed in the number of rotifer associated (1.8–7.6 · 103 colony forming units per rotifer–1) and free-living (0.6–25 107 cells·ml–1) bacteria. An increase of 50–150% in the bacterial number was normally observed after feeding the rotifer with squid meal, but after three days of acclimation at 6 °C, the bacterial numbers decreased to the initial level.After enrichment of the cultures with squid meal, the similarity in the composition of the bacterial flora between the rotifers and water was reduced. However, acclimation of the culture at 6 °C resulted in better agreement of the rotifer associated flora and that in water. Enrichment of the cultures induced a shift in the bacterial composition from Cytophaga/Flavobacterium dominance to Pseudomonas/Alcaligenes dominance. The bacterial flora of the rotifer cultures are dominated by presumably opportunistic species after enrichment, which may have detrimental effects when rotifers are fed as live food to marine fish larvae. 相似文献
19.
Removal of bisphenol A by polymerization and precipitation method using Coprinus cinereus peroxidase
Bisphenol A was efficiently removed by the polymerization and precipitation method using Coprinus cinereus peroxidase. The removal efficiency was optimal between pH 9–10 and at 40 °C with a molar ratio of H2O2 to bisphenol A of about 2. To remove 100 mg bisphenol A l–1, peroxidase was required 5 U ml–1 at pH 7 and 25 °C and 3 U ml–1 at pH 10 and 40 °C. 相似文献
20.
Kluyveromyces marxianus was grown in submerged culture in a complex medium with several potential inducers of lipolytic activity (triacylglycerols, fatty acids). The highest extracellular lipolytic enzyme production (about 80 U ml–1 in 3 d) was obtained when the medium was supplemented with 2 g urea l–1 plus 5 g tributyrin l–1. Addition of surfactants (1 g l–1) did not improve production. The lipase had a high thermal stability in aqueous solution (73% residual activity after 9 d at 50 °C, 16 min half-life time at 100 °C). It was also stable at acidic pH and showed good tolerance to organic solvents (70% residual activity after 2 d in n-hexane of cyclohexane). 相似文献