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1.
A. I. Kopylov D. B. Kosolapov E. A. Zabotkina T. S. Maslennikova 《Inland Water Biology》2016,9(4):359-367
Virioplankton and bacterioplankton abundance has been determined in the pelagic and littoral zones of the Rybinsk Reservoir during the ice-covered period. The role of viruses in heterotrophic bacterioplankton infection and mortality is assessed. At water temperatures between 0.3 and 0.9°C, the number of planktonic virus particles and planktonic bacteria varies from 37.1 × 106 to 84.1 × 106 particles/mL, (57.3 ± 2.1) × 106 particles/mL on average and from 2.50 × 106 to 6.11 × 106 cells/mL, (3.66 ± 0.16) × 106 cells/mL on average, respectively. The ratio of the virus number to the bacteria number varies from 8.8 to 27.9, being 16.5 ± 0.7 on average. Visually infected cells comprise 0.3–0.5% (1.5 ± 0.2% on average) of the total number of bacterioplankton. Infected bacterial cells contain from 5 to 107 (17 ± 4 on average) mature virus particles. The average virus-induced mortality of bacteria accounts for 13.0 ± 1.9% (variations range from 2 to 55%) of the daily bacterial production, indicating that viruses play an important role in the regulation of bacterioplankton production and abundance in the Rybinsk Reservoir during the ice-covered period. 相似文献
2.
Abundance, biomass, and taxonomic composition of heterotrophic nanoflagellates (HNFs) have been determined in the water column and bottom sediments of the large lowland meso-eutrophic reservoir (Rybinsk Reservoir, Upper Volga) in summer. The role of HNFs in the consumption of the bacterial production is estimated. In the reservoir, 55 species from 15 large taxa, including 35 species from the plankton, are identified and 45 species are from benthos samples. The orders Kinetoplastida, Choanomonada, and Chrysomonadida are distinguished by the highest species diversity. Abundance and biomass of HNFs in the water column average 991 ± 326 cells/mL and 41.4 ± 14.1 mg/m3, while in the bottom sediments they are (236 ± 61) × 103 cells/mL and 10.7 ± 4.0 μg/mL, respectively. The biomass of HNFs average 11.2% of the bacterial biomass in the water column and only 0.8% of that in the sediments. Flagellates are found to be a major factor which control the development of bacterioplankton grazing, on average, 32.3% of its daily production, whereas their impact on bacteriobenthos is insignificant, as they consume, on average, only 2.0% of its production. 相似文献
3.
A. I. Kopylov D. B. Kosolapov E. A. Zabotkina E. V. Rumyantseva 《Inland Water Biology》2016,9(3):251-257
The total number and morphological and size composition of viriobenthos, number of bacteria infected by viruses, and burst size, as well as virus-induced mortality, abundance, and production of bacteriobenthos, have been estimated in bottom sediments of the Rybinsk Reservoir. The total number of viriobenthos in the reservoir varies within (1.1–10.9) × 109 (on average, (5.9 ± 0.6) × 109) particles/cm3; the total number of virus-to-bacteria ratio ranges within 0.2–2.1 (on average 0.9 ± 0.3). A weak positive correlation is found between the abundance of benthic viruses and the abundance and production of benthic bacteria. In most surveyed parts of the reservoir, infected benthic bacteria were not found or the portion of visibly infected bacterial cells (FVIC) did not exceed 0.5% of the total abundance of bacteriobenthos (N B). A comparatively high infection of bacteria by viruses was recorded in bottom sediments only at one deep-water station, where FVIC was 2.5 of N B. 相似文献
4.
M. P. Venger A. I. Kopylov E. A. Zabotkina P. R. Makarevich 《Russian Journal of Marine Biology》2016,42(1):26-35
The viral and bacterioplankton communities of the Barents Sea were investigated using a combination of methods of electron and epifluorescence microscopy for the first time. The quantitative composition of the communities and the nature of their interactions were also determined. Our study showed that during the summer the abundance and biomass of bacterioplankton reached 0.4–4.0 × 106 cells/mL and 25.09–84.21 mg/m3 in offshore waters and 0.4–1.8 × 106 cells/mL and 19.63–100.19 mg/m3 in coastal waters, respectively. In both regions, the number of viruses (1.7–35.8 × 106 and 14.5–32.4 × 106 particles/mL) exceeded the number of bacteria by 2–31 and 13–60 times, respectively; the average viral production was 0.75106 and 1.74 × 106 particles/mL/day, respectively. The proportion of infected cells in the total bacterioplankton (7% on average) and virus-induced mortality of bacteria (8%) were much lower in offshore than in coastal waters (14 and 20%, respectively). 相似文献
5.
DEAE-cellulose-purified Trypanosoma lewisi from 4-day (dividing trypanosomes) and 7-day (non-dividing trypanosomes) infections in rats were compared for initial uptake of glucose, leucine, and potassium. Glucose entered the parasitic cells by mediated (saturable) processes, whereas leucine and K+ entered by mediated processes and diffusion. Glucose entry was significantly elevated in 4-day cells (Vmax 4.00 ± 1.02 nmoles/ 1 × 108 cells/min) with respect to 7-day cells (Vmax 1.83 ± 0.62 nmoles 1 × 108 cells/min). Likewise, the affinity of the glucose carrier was significantly greater in 4-day cells (Km = 0.30 ± 0.02 mM) than in 7-day cells (Km = 0.59 ± 0.11 mM). When leucine and K+ transport were compared in 4- and 7-day populations, significant elevations in the rate of entry (Vmax) of both substrates were observed for 4-day cells; Km values for leucine and K+ were not altered by the stage of infection. For leucine, the Vmax and Km for 4-day cells were 2.40 ± 0.50 nmoles/1 × 108 cells/30 sec and 78 ± 7 μM, respectively; corresponding values in 7-day cells were 1.06 ± 0.02 nmoles/1 × 108 cells/30 sec and 66 ± 11 μM. For K+, the Vmax and Km for 4-day cells were 15.97 ± 0.38 nmoles/1 × 108 cells/min and 1.2 mM, respectively; corresponding values in 7-day cells were 4.76 ± 1.82 nmoles/1 × 108 cells/min and 1.05 mM. The observed increase in the rate of K+ entry into 4-day cells was attributable to enhanced influx; no significant difference in the rate of K+ efflux was noted when 4- and 7-day cells were compared ( of K+ leak for 4- and 7-day cells were 68.1 ± 9.3 and 67.9 ± 15.2 min, respectively). Potassium influx was ouabain insensitive. Membrane function in 7-day cells was not uniformly inhibited. No significant difference in the activity of the membrane-bound enzyme, 5′-nucleotidase, was observed when 4- and 7-day cells were compared. 相似文献
6.
The optimization of bioreactor operations towards swainsonine production was performed using an artificial neural network coupled evolutionary program (EP)-based optimization algorithm fitted with experimental one-factor-at-a-time (OFAT) results. The effects of varying agitation (300–500 rpm) and aeration (0.5–2.0 vvm) rates for different incubation hours (72–108 h) were evaluated in bench top bioreactor. Prominent scale-up parameters, gassed power per unit volume (P g/V L, W/m3) and volumetric oxygen mass transfer coefficient (K L a, s?1) were correlated with optimized conditions. A maximum of 6.59 ± 0.10 μg/mL of swainsonine production was observed at 400 rpm-1.5 vvm at 84 h in OFAT experiments with corresponding P g/VL and K L a values of 91.66 W/m3 and 341.48 × 10?4 s?1, respectively. The EP optimization algorithm predicted a maximum of 10.08 μg/mL of swainsonine at 325.47 rpm, 1.99 vvm and 80.75 h against the experimental production of 7.93 ± 0.52 μg/mL at constant K L a (349.25 × 10?4 s?1) and significantly reduced P g/V L (33.33 W/m3) drawn by the impellers. 相似文献
7.
《Animal reproduction science》1998,51(3):249-257
Receptors for luteinizing hormone/human chorionic gonadotropin (LH/hCG) have been identified in porcine, rabbit, rat, and human myometrium. To determine the estrous cycle and pregnancy related changes in the receptor capacity and affinity, radioreceptor assays were performed with membrane homogenates of porcine uterine tissues. Cycling gilts were divided into four experimental groups: I (n=6), day 1–2; II (n=5), day 6–7; III (n=5), day 11–12; and IV (n=6), day 18–20 of the estrous cycle. Pregnant pigs were divided into three experimental groups: I (n=5), day 35–40; II (n=5), day 65–70; and III (n=4), day 95–105 of pregnancy. The concentrations [femtomoles/mg protein (fmol/mg protein)] and affinities of unoccupied LH/hCG binding sites were characterized in all samples of myometrium. Receptor concentrations were highest (P<0.01) in groups II and III (19.3±2.5 and 35.8±2.1 fmol/mg protein, respectively), and was lowest in groups I and IV (5.3±1.4 and 7.5±0.7 fmol/mg protein, respectively). Receptor affinity constants (Ka) were consistent (P>0.05) throughout the estrous cycle [I, (5.1±1.5)×109; II, (3.0±0.8)×109; III, (3.2±0.9)×109; IV, 5.5±0.7×109 lm−1]. Plasma hormone concentrations of progesterone, estrogen and LH were typical of values noted at these times. During pregnancy, receptor concentrations were greatest (P<0.05) in group II (85.4±18.5 fmol/mg protein). In groups I and III receptor numbers were 10.8±2.3 and 26.7±6.6 fmol/mg protein, respectively. The Ka in group I was 10 times greater (P<0.05) than Ka in groups II and III, (I, 3.1±0.9×1010 lm−1; II, 3.4±0.3×109 lm−1; III, 3.3±1.1×109 lm−1). Plasma hormone concentrations typically found during pregnancy were noted. The function of these LH/hCG binding sites remains unknown; however, changes in receptor capacity during the estrous cycle and pregnancy support a role for modulation of the receptor by hormonal factors. 相似文献
8.
Yitao Wang Dong Xu Xiao Fan Xiaowen Zhang Naihao Ye Wenqi Wang Yuze Mao Shanli Mou Shaona Cao 《Journal of applied phycology》2013,25(2):631-637
In order to illustrate the physiological variation of different generations and different thallus parts of Saccharina japonica, physiological parameters such as maximum and effective PSII photochemical efficiency, nutrient uptake, and elemental composition were determined in the laboratory. Photosynthetic analysis in different generations indicated that, although gametophytes had higher pigment contents than the sporophyte, they had lower values of F v/F m and ΔF/F′m. The highest Chl a/Chl c ratio was found in sporophyte generation (3.98?±?0.01) and in the basal part of fresh thallus (2.66?±?0.02). The sporophyte had significantly higher values of nitrate uptake but lower values of phosphorus uptake than the gametophytes. The contents of nitrogen and carbon as well as C/N in gametophytes were significantly higher than those in sporophytes. In addition, the basal part of the S. japonica thallus had the highest C content (22.31?±?1.50 %) but the lowest N content (2.02?±?0.16 %), as well as the highest value of C/N (11.02?±?0.34). 相似文献
9.
The species composition and abundance of phytoplankton were determined in the Baidarata Inlet (Kara Sea) in August 2005 and July and September–October 2007. A total number of 220 species were found. In the surface layer, phytoplankton biomass ranged from 1.5 to 15.4 mg C/m3 (mean 5.7 ± 3.0 mg C/m3) in July, from 1.2 to 11.8 mg C/m3 (mean 5.2 ± 2.8 mg C/m3) in August, and from 4.4 to 22.6 mg C/m3 (mean 12.8 ± 5.6 mg C/m3) in September-October. In July at different sampling sites, the biomass was dominated by dinoflagellates, diatoms, and chrysophycean. Dinoflagellates dominated at almost all stations in August. Diatoms dominated in autumn with the most abundant species Paralia sulcata. 相似文献
10.
In leaves of the mangrove species Avicennia germinans (L.) L. grown in salinities from 0 to 40 ‰, fluorescence, gas exchange, and δ13C analyses were done. Predawn values of Fv/Fm were about 0.75 in all the treatments suggesting that leaves did not suffer chronic photoinhibition. Conversely, midday Fv/Fm values decreased to about 0.55-0.60 which indicated strong down-regulation of photosynthesis in all treatments. Maximum photosynthetic rate (P max) was 14.58 ± 0.22 µmol m-2 s-1 at 0 ‰ it decreased by 21 and 37 % in plants at salinities of 10 and 40 ‰, respectively. Stomatal conductance (g s) was profoundly responsive in comparison to P max which resulted in a high water use efficiency. This was further confirmed by δ13C values, which increased with salinity. From day 3, after salt was removed from the soil solution, P max and g s increased up to 13 and 30 %, respectively. However, the values were still considerably lower than those measured in plants grown without salt addition. 相似文献
11.
V. V. Tikhonov D. S. Orlov O. V. Lisovitskaya Yu. A. Zavgorodnyaya B. A. Byzov V. V. Demin 《Microbiology》2013,82(6):707-712
Capacity for sorption of humic acid (HA) from water solutions was shown for 38 bacterial strains. Isotherms of HA sorption were determined for the cells of 10 strains. The bonding strength between the cells and HA (k) and the terminal adsorption (Q max) determined from the Langmuir equation for gram-positive and gram-negative bacteria were reliably different. Gram-positive bacteria sorbed greater amounts of HA than gram-negative ones (Q max = 23 ± 10 and 5.6 ± 1.2 mg/m2, respectively). The bonding strength between HA and the cells was higher in gram-negative bacteria than in gram-positive: k = 9 ± 5 and 3.3 ± 1.1 mL/mg, respectively. 相似文献
12.
Ibuprofen, one of the nonsteroidal anti-inflammatory drugs, inhibited arylamine N-acetyltransferase activity of Klebsiella pneumoniae both in vitro and in vivo. The NAT activities of Klebsiella pneumoniae were inhibited by ibuprofen in a dose-dependent manner both in vitro and in vivo. In vitro, the NAT activity was 0.675 ±
0.028 nmol/min/mg of protein for the acetylation of 2-aminofluorene. In the presence of 8 mM ibuprofen, the NAT activity was
0.506 ± 0.002 nmol/min/mg of protein for the acetylation of 2-aminofluorene. In vivo, the NAT activity was 0.279 ± 0.016 nmol/min/1010 colony forming units (CFU) for the acetylation of 2-aminofluorene. In the presence of 8 mM ibuprofen, the NAT activity was
0.228 ± 0.008 nmol/min/1010 CFU for the acetylation of 2-aminofluorene. The inhibition of NAT activity by ibuprofen was shown to persist for at least
4 h. For in vitro examination, the values of apparent K
m
and V
max were 1.08 ± 0.05 mM and 9.17 ± 0.11 nmol/min/mg of protein, respectively, for 2-aminofluorene. However, when 8 mM of ibuprofen
was added to the reaction mixtures, the values of apparent K
m
and V
max were 1.19 ± 0.01 mM and 6.67 ± 0.11 nmol/min/mg of protein, respectively, for 2-aminofluorene. For in vivo examination, the
values of apparent K
m
and V
max were 1.24 ± 0.48 mM and 4.18 ± 1.06 nmol/min/10 × 1010 CFU, respectively, for 2-aminofluorene. However, when 8 mM of ibuprofen was added to the culture, the values of apparent
K
m
and V
max were 0.95 ± 0.29 mM and 2.77 ± 0.37 nmol/min/mg protein, respectively, for 2-aminofluorene, respectively. This report is
the first finding of ibuprofen inhibition of arylamine N-acetyltransferase activity in a strain of Klebsiella pneumoniae.
Received: 28 January 1997 / Accepted: 12 February 1997 相似文献
13.
Agmatine iminohydrolase was purified ca 375-fold from groundnut cotyledons. The enzyme exhibited an optimum pH between 5.5 and 8.5 and the energy of activation was 22 kcal/mol. The Km for agmatine was (7.57 ± 0.77) × 10?4 M. The enzyme was inhibited by tryptamine, putrescine, cadaverine, spermidine and spermine. Inhibition by cadaverine and spermidine was competitive. The Ki values for cadaverine and spermidine were 4.1 × 10?3 and 7.5 × 10?4 M, respectively. 相似文献
14.
V. G. Dvoretskii 《Biology Bulletin》2011,38(4):393-399
New data have been obtained on the spatial distribution of the early developmental stages of Malacostraca in the mesozooplankton of the southern Barents Sea. In spring 2007, the euphausiid stages with the highest abundance (over 80%) were eggs and nauplii. Decapod larvae were represented by zoeae of Paralithodes camtschaticus, Pagurus pubescens, and Hyas araneus; their abundance was at most 1.5% of total zooplankton abundance. The larvaton groups dominant by abundance were furciliae of Euphasiacea (14.5 ± 6.2 mg/m3) and zoeae of P. camtschaticus (32.7 ± 15.9 mg/m3). The size structure of larval hemipopulations was similar over the studied water area. Comparison with data on the larval body length obtained in other areas of the sea leads to a conclusion on the independence of the decapod groups of Eastern and Western Murman. 相似文献
15.
Nicolas Soumis Marc Lucotte Catherine Larose François Veillette René Canuel 《Biogeochemistry》2007,86(2):123-135
In order to evaluate the role of photochemistry in the carbon dioxide (CO2) generation from a 10-year-old boreal reservoir, the photomineralization of dissolved organic matter (DOM) was assessed and
compared to a boreal river as well as to boreal and temperate lakes during July and August, 2003. Sterile water samples were
irradiated by sunlight over the whole photoperiod and subsequently analyzed for CO2. Mean energy-normalized apparent photochemical yield of CO2 (an index of DOM photoreactivity normalized for the energy absorbed by samples) was significantly higher in the reservoir
(27.7 ± 13.0 mg CO2·m−3·kJ−1) and the boreal river (35.8 ± 2.3 mg CO2·m−3·kJ−1) than in the boreal lakes (15.5 ± 5.1 mg CO2·m−3·kJ−1). The DOM photoreactivity of the temperate lakes (20.9 ± 8.1 mg CO2·m−3·kJ−1) was not statistically different from any type of boreal water bodies. There was no significant difference in either the
integrated photoproduction of CO2 (273–433 mg CO2·m−2·d−1) or the potential photochemical contribution to CO2 diffusive fluxes (56–92%) among these water bodies. DOM photoreactivity was significantly affected by the cumulative hydrological
residence time (CHRT) when considering the whole data set. However, when considering only the boreal water bodies, iron (Fe)
and manganese (Mn) also intervened. The fact that DOM photoreactivity was related to CHRT as well as to Fe and Mn concentrations,
which are respectively permanent and long-lasting features of the reservoir, suggests that the photoproduction of CO2 is not likely to decrease over time. This process may therefore play a substantial role in the long-term CO2 emissions from boreal reservoirs during the summer, its potential contribution to CO2 diffusive fluxes being estimated at 56 ± 29 %. 相似文献
16.
长江口及邻近海域富营养化指标响应变量参照状态的确定 总被引:1,自引:0,他引:1
对长江口富营养化指标中的响应变量进行了筛选,并在长江口分区的基础上,运用参照点或观测点指标频数分布曲线法,对1992年-2010年的数据进行分析,确定了长江口外海区和舟山海区富营养化指标中响应变量的参照状态.选择叶绿素a和底层溶解氧作为响应指标的必选指标,浮游植物密度和CODMn作为辅助指标.经分析,长江口口外海区叶绿素a、浮游植物密度、CODMn和底层溶解氧的春夏秋3个季节的参照状态分别为0.87mg,/m3,17.44× 103个/L,0.42mg/L,8.36mg/L;1.88mg/m3,25.96×103个/L,0.56mg/L,4.22mg/L;0.84mg/m3,12.10×103个/L,0.46mg/L,6.95mg/L;舟山海区叶绿素a、浮游植物密度、CODMn和溶解氧的春夏秋3个季节的参照状态分别为0.73mg/m3,6.77×103个/L,0.51 mg/L,8.75mg/L;1.00mg/m3,9.72×103个/L,0.37mg/L,5.94mg/L;0.78mg/m3,4.59×103个/L,0.55mg/L,7.40mg/L.本研究确定的参照状态值能较为客观的反映该海域的富营养化参照状态,且不同分区,不同季节间的指标的参照状态亦存在着显著的差异. 相似文献
17.
Harinder S. Hundal Peter M. Taylor Nicholas M. Willhoft Bryan Mackenzie Sylvia Y. Low Martyn R. Ward Michael J. Rennie 《生物化学与生物物理学报:疾病的分子基础》1992,1180(2):137-146
We wished to examine the effects of diabetes on muscle glutamine kinetics. Accordingly, female Wistar rats (200 g) were made diabetic by a single injection of streptozotocin (85 mg/kg) and studied 4 days later; control rats received saline. In diabetic rats, glutamine concentration of gastrocnemius muscle was 33% less than in control rats: 2.60 ± 0.06 μmol/g vs. 3.84 ± 0.13 μmol/g (P < 0.001). In gastrocnemius muscle, glutamine synthetase activity (Vmax) was unaltered by diabetes (approx. 235 nmol/min per g) but glutaminase Vmax increased from 146 ± 29 to 401 ± 94 nmol/min per g; substrate Km values of neither enzyme were affected by diabetes. Net glutamine efflux (AZ concentration difference × blood flow) from hindlimbs of diabetic rats in vivo was greater than control values (?30.0 ± 3.2 vs. ?1.9 ± 2.6 nmol/min per g (P < 0.001) and hindlimb NH3 uptake was concomitantly greater (about 27 nmol/min per g). The glutamine transport capacity (Vmax) of the Na-dependent System Nm in perfused hindlimb muscle was 29% lower in diabetic rats than in controls (820 ± 50 vs. 1160 ± 80 nmol/min per g (P < 0.01)), but transporter Km was the same in both groups (9.2 ± 0.5 nM). The difference between inward and net glutamine fluxes indicated that glutamine efflux in perfused hindlimbs was stimulated in diabetes at physiological perfusate glutamine (0.5 mM); ammonia (1 mM in perfusate) had little effect on net glutamine flux in control and diabetic muscles. In Intramuscular Na+ was 26% greater in diabetic (13.2 μmol/g) than control muscle, but muscle K+ (100 μmol/g) was similar. The accelerated rate of glutamine release from skeletal muscle and the lower muscle free glutamine concentration observed in diabetes may result from a combination of; (i), a diminished Na+ electrochemical gradient (i.e., the net driving force for glutamine accrual in muscle falls); (ii), a faster turnover of glutamine in muscle and (iii), an increased Vmax/Km for sarcolemmal glutamine efflux. 相似文献
18.
The hydropower reservoirs, considered as a green source of energy, are now found to emit significant quantities of greenhouse gas (GHG) to the atmosphere. This article attempts to predict the vulnerability of Tehri reservoir, India to GHG emissions using the GHG risk assessment tool (GRAT). The GRAT is verified with experimental GHG fluxes. The annual mean CO2 fluxes from diffusion, bubbling, and degassing were 425.93 ± 122.50, 4.81 ± 1.33, and 7.01 ± 2.77 mg m?2d?1, whereas CH4 fluxes were 23.11 ± 7.08, 4.79 ± 1.08, and 7.41 ± 4.50 mg m?2d?1, respectively, during 2011–12. The model found that Tehri reservoir emitted higher CO2 and CH4 (i.e., 790 mg m?2d?1 and 64 mg m?2d?1, respectively) in 2011, which came within vulnerability range causing more climate change impact. By the year 2015, it would scale down to medium risks necessitating no further assessment of GHG. Significant difference between predicted and experimental GHG emission are assessed, which may be due to insufficient data, spatial and temporal variations, decomposition of flooded biomass, limitation of GRAT model, and inadequate methodology. The study reveals that GHG emission from Tehri reservoir is less than predicted by the GRAT. 相似文献
19.
In July-August 2009, the abundance of picophytoplankton (Pico) in the Velikaya Salma strait varied from 3.4 × 106 to 19.4 × 106 cells/L, while its biomass (B) was 0.8–3.3 mg C/m3. In August 2010, Pico abundance was significantly higher (up to 216 × 106 cells/L and 36.8 mg C/m3). Pico consisted mainly of cyanobacteria. It constituted 13 (2009) to 28% (2010) of the total phytoplankton biomass. In April 2010, Pico numbers varied from 0.1 × 106 to 0.22 × 106 cells/L and its biomass was 0.05–0.28 mg C/m3. Picoeukaryotes were predominant. Pico constituted not more than 2.7% of the phytoplankton biomass. In the ice column, the integrated Pico abundance was 430 × 106 cells/m2 and the integrated biomass was 365 μg C/m2. 相似文献
20.
A solventogenic strain of Clostridium sp. BOH3 produces extracellular α-amylase (7.15 U/mg protein) in reinforced clostridial medium supplemented with sugarcane bagasse hydrolysate (1 % w/v) and a small amount of starch (0.1 % w/v), which is essential for the expression of α-amylase. In the presence of α-amylase, BOH3 utilizes starch directly without any pretreatment and produces butanol almost equivalent (~90 %) to the production of butanol from glucose. α-Amylase can be purified from culture supernatant by using one-step weak anion exchange chromatography with a yield of 43 %. In peptide fingerprinting analysis, this enzyme shows homology with α-amylase produced by Clostridium acetobutylicum ATCC824. However, the molecular weight is 54 kDa, which is smaller than α-amylase of ATCC824 (84 kDa). This enzyme has optimum temperature at 45–50 °C and optimum pH at 4.5–5.5. Under this condition, the enzyme activity is 91.32 U/mg protein, and its K m and V max values are 1.71?±?0.02 mg/ml and 96.13?±?0.15 μmol/min/mg protein, respectively. Activity of this α-amylase can be enhanced (>1.5 times) by addition of Ca2+ and Co2+ and its activity can be maintained at an acidic pH (pH 3–5) for about 24 h. These unique characteristics suggest that this enzyme can be used for saccharification of starch for production of biofuel in one pot. 相似文献