共查询到20条相似文献,搜索用时 46 毫秒
1.
M. De Pirro G. Santini G. Chelazzi 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(7):501-506
Cardiac activity of two Mediterranean limpets was tested at different salinities. Patella caerulea inhabits the lower midlittoral where it is exposed to variations in salinity, while P. aspera experiences more stable salinity conditions in the infralittoral fringe. When exposed to moderate hypo- and hypersalinity
(23 g l−1 and 43 g l−1) for 24 min, P. caerulea showed no significant variation in heart rate with respect to the control salinity (33 g l−1), while P. aspera exhibited a significant increase in heart rate in both conditions. This suggests a rise in metabolic rate due to activation
of behavioural responses or physiological regulation. When exposed to extremely low salinity (3 g l−1) for 24 min, heart contractions ceased in most specimens of P. caerulea. A smaller number of specimens also displayed cessation of heart beat when exposed to extremely high salinity (63 g l−1). The heart beat resumed quickly in all specimens when they were returned to control salinity conditions. In contrast, cardiac
activity was not interrupted in any of the P. aspera specimens at the 3 g l−1 and 63 g l−1 salinity levels, but strong bradycardia was evident. Contractile activity of the heart ceased in all specimens of P. caerulea and P. aspera when they were exposed to prolonged hypo-osmotic stress (3 g l−1 for 24 h). This acardia was largely reversible in P. caerulea, but most specimens of P. aspera did not recover from the treatment.
Accepted: 3 July 1999 相似文献
2.
Interactions between microbial growth and substrate degradation are important in determining the performance of trickle-bed
bioreactors (TBB), especially when salt is added to reduce biomass formation in order to alleviate media clogging. This study
was aimed at quantifying salinity effects on bacterial growth and substrate degradation, and at acquiring kinetic information
in order to improve the design and operation of TBB. Experiment works began by cultivating a mixed culture in a chemostat
reactor receiving artificial influent containing a mixture of benzene, toluene, and xylene (BTX), followed by using the enrichment
culture to degrade the individual BTX substrates under a particular salinity, which ranged 0–50 g l−1 in batch mode. Then, the measured concentrations of biomass and residual substrate versus time were analyzed with the microbial
kinetics; moreover, the obtained microbial kinetic constants under various salinities were modeled using noncompetitive inhibition
kinetics. For the three substrates the observed bacterial yields appeared to be decreased from 0.51–0.74 to 0.20–0.22 mg mg−1 and the maximum specific rate of substrate utilization,
declined from 0.25–0.42 to 0.07–0.11 h−1, as the salinity increased from 0 to 50 NaCl g l−1. The NaCl acted as noncompetitive inhibitor, where the modeling inhibitions of the coefficients, K
T(S), were 22.7–29.7 g l−1 for substrate degradation and K
T(μ), 13.0–19.0 g l−1, for biomass formation. The calculated ratios for the bacterial maintenance rate, m
S, to
further indicated that the percentage energy spent on maintenance increased from 19–24 to 86–91% as salinity level increased
from 0 to 50 g l−1. These results revealed that the bacterial growth was more inhibited than substrate degradation by the BTX oxidizers under
the tested salinity levels. The findings from this study demonstrate the potential of applying NaCl salt to control excessive
biomass formation in biotrickling filters. 相似文献
3.
The combined effect of temperature, food level and the presence of an invertebrate predator on the body size of the rotifer
Brachionus havanaensis were tested in this study. B. havanaensis was cultured at 15, 20, and 25°C under three different Chlorella vulgaris levels (0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1) in the presence and in the absence of Asplanchna girodi. For each treatment we maintained three replicates and constant (0.4 ind ml−1) population density of B. havanaensis. In treatments containing A. girodi, the predator was separated from the prey by a mesh (pore size 50 μm). On the last day of the experiment, a portion of the
B. havanaensis population was sampled for several morphometric measurements (adult lorica length, width, posterior spine length, body volume,
and the egg volume). Size measurements were done by drawing the specimens using a calibrated camera lucida. Statistically
significant impact of temperature as well as the predator’s presence was observed on the lorica length, posterior spine, and
egg volume of B. havanaensis. The interactions of food × temperature, or predator′s presence × food × temperature were non-significant (P > 0.05) for lorica length, spine length, body volume, and egg volume. Regardless of the type of treatment, there was a direct
positive correlation between lorica length and width. Egg volume was linearly related to the adult size. Notably long posterior
spines were observed in treatments containing the presence of A. girodi.
Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont & R. Rico-Martínez.
Advances in Rotifer Research 相似文献
4.
J. Y. Takekawa A. K. Miles D. C. Tsao-Melcer D. H. Schoellhamer S. Fregien N. D. Athearn 《Hydrobiologia》2009,626(1):155-168
Salt evaporation ponds have existed in San Francisco Bay, California, for more than a century. In the past decade, most of
the salt ponds have been retired from production and purchased for resource conservation with a focus on tidal marsh restoration.
However, large numbers of waterbirds are found in salt ponds, especially during migration and wintering periods. The value
of these hypersaline wetlands for waterbirds is not well understood, including how different avian foraging guilds use invertebrate
prey resources at different salinities and depths. The aim of this study was to investigate the dietary flexibility of waterbirds
by examining the population number and diet of three feeding guilds across a salinity and depth gradient in former salt ponds
of the Napa-Sonoma Marshes. Although total invertebrate biomass and species richness were greater in low than high salinity
salt ponds, waterbirds fed in ponds that ranged from low (20 g l−1) to very high salinities (250 g l−1). American avocets (surface sweeper) foraged in shallow areas at pond edges and consumed a wide range of prey types (8) including
seeds at low salinity, but preferred brine flies at mid salinity (40–80 g l−1). Western sandpipers (prober) focused on exposed edges and shoal habitats and consumed only a few prey types (2–4) at both
low and mid salinities. Suitable depths for foraging were greatest for ruddy ducks (diving benthivore) that consumed a wide
variety of invertebrate taxa (5) at low salinity, but focused on fewer prey (3) at mid salinity. We found few brine shrimp,
common in higher salinity waters, in the digestive tracts of any of these species. Dietary flexibility allows different guilds
to use ponds across a range of salinities, but their foraging extent is limited by available water depths.
Guest Editors: J. John & B. Timms
Salt Lake Research: Biodiversity and Conservation—Selected papers from the 9th Conference of the International Society for
Salt Lake Research 相似文献
5.
Effects of macrophyte growth forms on invertebrate communities in saline lakes of the Wyoming High Plains 总被引:1,自引:1,他引:0
In saline lakes, areal cover and both species and structural diversity of macrophytes often decline as salinity increases.
To assess effects of the loss of certain macrophyte growth forms, we characterized benthic and epiphytic invertebrates in
three growth forms (thin-stemmed emergents, erect aquatics, and low macroalgae) in oligosaline lakes (0.8–4.2 mS cm−1) of the Wyoming High Plains, USA. We also measured the biomass and taxonomic composition of epiphytic and benthic invertebrates
in two erect aquatics with very similar structure that are found in both oligosaline (Potamogeton pectinatus) and mesosaline (9.3–23.5 mS cm−1) (Ruppia maritima) lakes. Although total biomass of epiphytic invertebrates varied among oligosaline lakes, the relative
distribution of biomass among growth forms was similar. For epiphytic invertebrates, biomass per unit area of lake was lowest
in emergents and equivalent in erect aquatics and low macroalgae; biomass per unit volume of macrophyte habitat was greatest
in low macroalgae. For benthic invertebrates, biomass was less beneath low macroalgae than other growth forms. Taxonomic composition
did not differ appreciably between growth forms for either benthic or epiphytic invertebrates, except that epiphytic gastropods
were more abundant in erect aquatics. Total biomass of epiphytic and benthic invertebrates for the same growth form (erect
aquatic) did not differ between oligosaline (Potamogeton pectinatus) and mesosaline (Ruppia maritima) lakes, but taxonomic composition did change. In the oligosaline to mesosaline range, direct toxic effects of salinity appeared
important for some major taxa such as gastropods and amphipods. However, indirect effects of salinity, such as loss of macrophyte
cover and typically higher nutrient levels at greater salinities, probably have larger impacts on total invertebrate biomass
lake-wide. 相似文献
6.
S. V. N. Vijayendra N. K. Rastogi T. R. Shamala P. K. Anil Kumar L. Kshama G. J. Joshi 《Indian journal of microbiology》2007,47(2):170-175
Polyhydroxyalkanotes (PHAs), the eco-friendly biopolymers produced by many bacteria, are gaining importance in curtailing
the environmental pollution by replacing the non-biodegradable plastics derived from petroleum. The present study was carried
out to economize the polyhydroxybutyrate (PHB) production by optimizing the fermentation medium using corn steep liquor (CSL),
a by-product of starch processing industry, as a cheap nitrogen source, by Bacillus sp. CFR 256. Response surface methodology (RSM) was used to optimize the fermentation medium using the variables such as
corn steep liquor (5–25 g l−1), Na2HPO4 2H2O (2.2–6.2 g l−1), KH2PO4 (0.5–2.5 g l−1), sucrose (5–55 g l−1) and inoculum concentration (1–25 ml l−1). Central composite rotatable design (CCRD) experiments were carried out to study the complex interactions of the variables.
The optimum conditions for maximum PHB production were (g l−1): CSL-25, Na2HPO4 2H2O-2.2, KH2PO4 − 0.5, sucrose − 55 and inoculum − 10 (ml l−1). After 72 h of fermentation, the amount of PHA produced was 8.20 g l−1 (51.20% of dry cell biomass). It is the first report on optimization of fermentation medium using CSL as a nitrogen source,
for PHB production by Bacillus sp. 相似文献
7.
The salinity tolerances of four species of small fishes native to the Murray-Darling river system were measured. Slow acclimation
LD50s were 43.7 ± 1.7 g L−1 for Craterocephalus stercusmuscarum Gunther, 38.0 ± 1.1 g L−1 for Hypseleotris klunzingeri (Ogilby), 58.7 ± 0.9 g L−1 for Retropinna semoni (Weber), and 29.8 ± 0.7 g L−1 for Melanotaenia splendida (Castelnau). The salinity tolerance of M. splendida was also measured by direct transfer, providing an estimated LD50 (infinite exposure time) of 20.8 g L−1, ∼ 70% of the slow acclimation value. Results suggest that at least adults of the species studied are under no threat from
present or foreseeable salinities in the Murray River. 相似文献
8.
K C A Bromley-Challenor N Caggiano J S Knapp 《Journal of industrial microbiology & biotechnology》2000,25(1):8-16
The degradation of N,N-dimethylformamide (DMF) by bacterial consortia was investigated under aerobic, fermentative and nitrate-reducing conditions
and a variety of salt concentrations (0.2%, 4% and 7% NaCl w/v) and pH values (5 and 7). Optimization of degradation conditions
was studied to provide information and recommendations for large-scale biological treatment processes. Under aerobic conditions,
mineralization of DMF (200 mg l−1, 2.7 mM) was achieved under all combinations of salinity and pH. The rate of bacterial growth decreased with increasing salinity.
Changes in the salt concentration and pH still resulted in mineralization and unchanged yield of bacterial cells. At 0.2%
NaCl and either pH 5 or 7, growth occurred on DMF in the range 0.2–1 g l−1. However, cell yield decreased with increasing concentrations of DMF. Under conditions of 0.2% NaCl, pH 7 and 4% NaCl, pH
5, growth on DMF at 5 g l−1 resulted in the production of an intermediate that was detected using gas chromatography (GC). It is proposed that the intermediate
was dimethylamine, and its persistence in growth media was attributed to suppressed growth as a result of an increase in pH.
A culture capable of degrading DMF under nitrate-reducing conditions was obtained at 0.2% NaCl and pH 7, but not at more saline
and acidic conditions. Growth and degradation of DMF were considerably slower under these conditions compared with aerobic
conditions. Fermentative degradation of DMF was not observed. Journal of Industrial Microbiology & Biotechnology (2000) 25, 8–16.
Received 14 July 1999/ Accepted in revised form 30 March 2000 相似文献
9.
H. G. Choi Y. S. Kim J. H. Kim S. J. Lee E. J. Park J. Ryu K. W. Nam 《Journal of applied phycology》2006,18(3-5):269-277
Effects of temperature and salinity on the growth of the two agarophytes, Gracilaria verrucosa (Hudson) Papenfuss and Gracilaria chorda Holmes were examined in Korea. Both species grew over a wide range of temperatures (10–30 ∘C) and salinities (5–35‰), and grew well at 17–30 ∘C and a salinity of 15–30‰. In culture, G. verrucosa grew faster than G. chorda and their maximum growth rates were 4.95% day−1 (30 ∘C, 25‰) and 4.47% day−1 (at 25 ∘C, 25‰), respectively. In the field population the maximum growth and fertility of G. chorda were observed in summer. The growth rate of G. verrucosa was slightly higher than that of G. chorda for 2 weeks on the cultivation rope and in culture but it was much lower after being contaminated with epiphytes. The biomass of the epiphytes was 0.82 g dry wt. per host plant in G. verrucosa and 0.001 g in G. chorda. G. chorda exhibited resistance to epiphytism and grew 7 times in length and the dry weight increased 15 times after 55 days. In conclusion, G. chorda appears to be a good agarophyte with a fast growth rate and resistance to epiphytesm, and compared with G. verrucosa, has good potential for commercial cultivation. 相似文献
10.
Synopsis Blood samples from cannulated young adult (2.5–15 kg) white sturgeon, acclimated to San Francisco Bay water (24 ppt) had plasma
values of 248.8 ± 13.5 mOsm kg−1 H2O, [Na+] = 125 ± 8.0 mEq 1−1, [K+] = 2.6 ± 0.8 mEq 1−1 and [CL−] = 122 ± 3.0 mEq 1−1. Freshwater acclimated sturgeon had an osmolality of 236 ± 7, [Na+] = 131.6 + 4.4, [K+] = 2.5 ± 0.7 and [CL−] = 110.6 ± 3.6. Freshwater acclimated fish gradually exposed to sea water (increase of 5 ppt h−1) had higher plasma osmolalities than did the bay water acclimated fish. These young adult sturgeon are able to tolerate transfer
from fresh water to sea water as well as gradual transfer from sea water to fresh water. Plasma electrolytes in transferred
fish are regulated, but tend to differ from long term acclimated fish at the same salinities. There is a gradual increase
in the upper salinity tolerance (abrupt transfer) of juvenile white sturgeon with weight: 5–10 ppt for 0.4–0.9 g fish, 10–15
ppt for 0.7–1.8 g fish, and 15 ppt for 4.9–50.0 g fish. The ability of juveniles to regulate plasma osmolality is limited.
The young adult fish are able to tolerate higher salinities (35 ppt) than juvenile sturgeon but probably are also characterized
by low activity of the necessary ion exchange mechanisms in the gills which permit rapid adjustment of blood electrolytes
with graduate change in external salinity. 相似文献
11.
Production of butanol from starch-based waste packing peanuts and agricultural waste 总被引:3,自引:0,他引:3
Jesse TW Ezeji TC Qureshi N Blaschek HP 《Journal of industrial microbiology & biotechnology》2002,29(3):117-123
We examined the fermentation of starch-based packing peanuts and agricultural wastes as a source of fermentable carbohydrates
using Clostridium beijerinckii BA101. Using semidefined P2 medium containing packing peanuts and agricultural wastes, instead of glucose as a carbohydrate
source, we measured characteristics of the fermentation including solvent production, productivity, and yield. With starch
as substrate (control), the culture produced 24.7 g l−1 acetone–butanol–ethanol (ABE), while with packing peanuts it produced 21.7 g l−1 total ABE with a productivity of 0.20 g l−1 h−1 and a solvent (ABE) yield of 0.37. Cell growth in starch, packing peanuts, and agricultural wastes medium was different,
possibly due to the different nature of these substrates. Using model agricultural waste, 20.3g l−1 ABE was produced; when using actual waste, 14.8 g l−1 ABE was produced. The use of inexpensive substrates will increase the economic viability of the conversion of biomass to
butanol, and can provide new markets for these waste streams. Journal of Industrial Microbiology & Biotechnology (2002) 29, 117–123 doi: 10.1038/sj.jim.7000285
Received 14 November 2001/ Accepted in revised form 07 June 2002 相似文献
12.
Vallero MV Lettinga G Lens PN 《Journal of industrial microbiology & biotechnology》2003,30(6):375-382
A laboratory-scale upflow anaerobic sludge bed (UASB) reactor was operated during 273 days at increasing NaCl concentrations (0.5–12.5 g NaCl l–1) to assess whether the stepwise addition of the salt NaCl results in the acclimation of that sludge. The 6.5-l thermophilic (55 °C), sulfidogenic [a chemical oxygen demand (COD) to SO42– ratio of 0.5] UASB reactor operated at an organic loading rate of 5 g COD l–1 day–1, a hydraulic retention time of 10 h and was fed with methanol as the sole electron donor. The results show that the adaptation of the thermophilic, sulfidogenic methanol-degrading biomass to a high osmolarity environment is unlikely to occur. Sulfide was the main mineralization product from methanol degradation, regardless of the NaCl concentration added to the influent. However, sulfide production in the reactor steadily decreased after the addition of 7.5 g NaCl l–1, whereas acetate production was stimulated at that influent NaCl concentration. Batch tests performed with sludge harvested from the UASB reactor when operating at different influent salinities confirmed that acetate is the main metabolic product at NaCl concentrations higher than 12.5 g l–1. The apparent order of NaCl toxicity towards the different trophic groups was found to be: sulfate-reducing bacteria > methane-producing archaea > acetogenic bacteria. 相似文献
13.
Manoj Kumar Vladimir León Angela De Sisto Materano Olaf A. Ilzins 《World journal of microbiology & biotechnology》2007,23(2):211-220
A Bacillus sp. strain DHT, isolated from oil-contaminated soil, grew and produced biosurfactant when cultured in variety of substrate
at salinities of up to 100 g l−1 and temperatures up to 45°C. It was capable of utilizing crude oil, fuels, various pure alkanes and PAHs as a sole carbon
and energy source across a wide range of temperature and salinity. Over the range evaluated, the degradation of hydrocarbon
and biosurfactant production was not influenced by salinity (0–10% wv−1) and temperature (30–45°C). The biosurfactant produced by the organism emulsified a range of hydrocarbons with hexadecane
as the best substrate and toluene as the poorest. From 16S rDNA analysis, strain DHT was related to Bacillus licheniformis. 相似文献
14.
A detailed survey was undertaken of the microbial communities of 16 saline lakes in the Vestfold Hills (Princess Elizabeth
Land, eastern Antarctica), which ranged in salinity from slightly brackish (4–5‰) to hypersaline (maximum: 174‰). Temperatures
at comparable sampling depths in the lakes ranged from −12.2°C to +10.5°C. Ranges in the abundances of bacteria, heterotrophic
nanoflagellates (HNAN) and phototrophic nanoflagellates (PNAN) were 1.40 × 107 l−1–1.58 × 1010 l−1, 4.83 × 104 l−1–1.70 × 107 l−1 and 0–1.02 × 107 l−1, respectively. There was considerable variation across the salinity spectrum, though in the case of bacteria and PNAN significantly
higher concentrations of cells were seen in two of the most saline lakes. The autotrophic ciliate Mesodinium rubrum occurred in all but five of the lakes and was found at salinity levels up to 108‰. Heterotrophic ciliates were generally
scarce. Dinoflagellates, particularly Gonyaulax c.f. tamarensis, Gyrodinium lachryma and Gymnodinium sp., occurred in the majority of the lakes. On the basis of chlorophyll a concentrations, nutrient levels and microplankton concentrations the lakes spanned the spectrum from ultra-oligotrophic to
oligo/mesotrophic. The most saline lakes had much reduced species diversity compared with the less saline environments. Isolation
from the marine environment has led to nutrient depletion, simplification and a truncated trophic structure.
Received: 19 September 1996 / Accepted: 13 January 1997 相似文献
15.
In this work, we quantified the life table demographic responses of Moina macrocopa daily exposed to three concentrations, 0, 0.08, 0.16, and 0.32 mg l−1 of CdCl2 for 3, 6, 12, and 24 h. These cadmium levels represented 10–50% of the median lethal concentration known for M. macrocopa. In general, increase in CdCl2 concentration and increase in the exposure time had a negative impact on the both survivorship and reproduction variables
of M. macrocopa. The survivorship curves showed drastic mortality of M. macrocopa exposed for 24 h per day at all three concentrations used. The survival of animals was distinctly lower than in controls
for the 3-h exposure at 0.08 mg l−1 of CdCl2. The cladocerans ceased to reproduce when exposed to 0.32 mg l−1 CdCl2 for 6 h or longer. Depending on the heavy metal concentration and the duration of exposure, the average lifespan, net reproductive
rate, generation time, and the rate of population increase varied from 3 to 10 days, 1 to 30 offspring female−1, 4 to 8 days, and −0.20 to +0.59 day−1, respectively. Even the lowest CdCl2 concentration for an exposure time of 3 h had an adverse effect on M. macrocopa, which suggested the importance of including pulsed exposure times in ecotoxicological evaluations. 相似文献
16.
The influence of toluene concentration on the specific growth rate, cellular yield, specific CO2, and metabolite production by Pseudomonas putida F1 (PpF1) was investigated. Both cellular yield and specific CO2 production remained constant at 1.0 ± 0.1 g biomass dry weight (DW) g−1 toluene and 1.91 ± 0.31 g CO2 g−1 biomass, respectively, under the tested range of concentrations (2–250 mg toluene l−1). The specific growth rate increased up to 70 mg toluene l−1. Further increases in toluene concentration inhibited PpF1 growth, although inhibitory concentrations were far from the application range of biological treatment processes. The specific
ATP content increased with toluene concentration up to toluene concentrations of 170 mg l−1. 3-Methyl catechol (3-MC) was never detected in the cultivation medium despite being an intermediary in the TOD pathway.
This suggested that the transformation from toluene to 3-MC was the limiting step in the biodegradation process. On the other
hand, benzyl alcohol (BA) was produced from toluene in a side chain reaction. This is, to the best of our knowledge, the first
reported case of methyl monoxygenation of toluene by PpF1 not harboring the pWW0 TOL plasmid. In addition, the influence of 3-MC, BA, and o-cresol on toluene degradation was investigated respirometrically, showing that toluene-associated respiration was not significantly
inhibited in the presence of 10–100 mg l−1 of the above-mentioned compounds. 相似文献
17.
Response of Periphytic Algae to Gradients in Nitrogen and Phosphorus in Streamside Mesocosms 总被引:2,自引:1,他引:1
In this study we manipulated both nitrogen and phosphorus concentrations in stream mesocosms to develop quantitative relationships
between periphytic algal growth rates and peak biomass with inorganic N and P concentrations. Stream water from Harts Run,
a 2nd order stream in a pristine catchment, was constantly added to 36 stream-side stream mesocosms in low volumes and then
recirculated to reduce nutrient concentrations. Clay tiles were colonized with periphyton in the mesocosms. Nutrients were
added to create P and N concentrations ranging from less than Harts Run concentrations to 128 μg SRP l−1 and 1024 μg NO3-N l−1. Algae and water were sampled every 3 days during colonization until periphyton communities reached peak biomass and then
sloughed. Nutrient depletion was substantial in the mesocosms. Algae accumulated in all streams, even streams in which no
nutrients were added. Nutrient limitation of algal growth and peak biomass accrual was observed in both low P and low N conditions.
The Monod model best explained relationships between P and N concentrations and algal growth and peak biomass. Algal growth
was 90% of maximum rates or higher in nutrient concentrations 16 μg SRP l−1 and 86 μg DIN l−1. These saturating concentrations for growth rates were 3–5 times lower than concentrations needed to produce maximum biomass.
Modified Monod models using both DIN and SRP were developed to explain algal growth rates and peak biomass, which respectively
explained 44 and 70% of the variance in algal response. 相似文献
18.
The objective of this work was to determine the influence of total dissolved solids/salinity (TDS mgL-1) on growth and biomass specific rates of nodularin (hepatotoxin) production by Nodularia spumigena 001E isolated from Lake Alexandrina, South Australia. Maximum biomass yield (dry matter, chlorophyll a and particulate organic carbon/POC) at 80 μmol photon m-2 s-1 was recorded at 3300 mg TDS L-1 and decreased at salinities above or below this value (p < 0.05). The maximum biomass yield (dry matter and chlorophyll a) at 30 μmol m-2 s-1 occurred at a higher salinity of 9900 mg TDS L-1. Cultures grown at 80 μmol m-2 s-1, at a TDS> 6600 mg L-1, had significantly (p < 0.05) lower nodularin content (ml-1 medium) than cultures grown at the same salinities at 30 μmolm-2 s-1. The maximum total toxin concentration (mL-1 medium) occurred at 9900 and 3300 mg TDS L-1 at 30 μmol m-2 s-1and 80 μmol m-2 s-1 respectively. Toxin per unit biomass, expressed as dry matter, chlorophyll a and POC was similar for cultures grown at 30 μmol m-2 s-1 or 80 μmol m-2s-1 at salinities < 6600 mg TDS L-1. At salinities > 9900 mg TDS L-1 the toxin content per unit biomass decreased at both irradiances, however, cultures grown at 30 μmol m-2s-1 had a higher toxin content than those grown at 80 μmol m-2 s-1. The results indicate that not only do changes in irradiance and salinity directly influence growth and toxin production
but that changes in irradiance affected the influence of salinity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
M-K Kim I-Y Lee J-H Lee K-T Kim Y-H Rhee Y-H Park 《Journal of industrial microbiology & biotechnology》2000,25(4):180-183
We investigated the influence of inorganic phosphate concentration on the production of curdlan by Agrobacterium species. A two-step culture method was employed where cells were first cultured, followed by curdlan production under nitrogen-limiting
conditions. In the curdlan production step, cells did not grow but metabolized sugar into curdlan. Shake-flask experiments
showed that the optimal phosphate concentration for curdlan production was in the range of 0.1–0.3 g l−1. As the cell concentration increased from 0.42 to 1.68 g l−1 in shake-flask cultures, curdlan production increased from 0.44 to 2.80 g l−1. However, the optimal phosphate concentration range was not dependent upon cell concentration. The specific production rate
was about 70 mg curdlan g-cell−1 h−1 irrespective of cell concentration. When the phosphate concentration was maintained at 0.5 g l−1 under nitrogen-limiting conditions, as high as 65 g l−1 of curdlan was obtained in 120 h. Journal of Industrial Microbiology & Biotechnology (2000) 25, 180–183.
Received 25 October 1999/ Accepted in revised form 21 July 2000 相似文献
20.
In order to understand the fate of PCP in upflow anaerobic sludge blanket reactor (UASB) more completely, the sorption and
biodegradation of pentachlorophenol (PCP) by anaerobic sludge granules were investigated. The anaerobic granular sludge degrading
PCP was formed in UASB reactor, which was seeded with anaerobic sludge acclimated by chlorophenols. At the hydraulic retention
time (HRT) of 20–22 h, and PCP loading rate of 200–220 mg l−1 d−1, UASB reactor exhibited good performance in treating wastewater which containing 170–180 mg l−1 PCP and the PCP removal rate of 99.5% was achieved. Sequential appearance of tetra-, tri-, di-, and mono-chlorophenol was
observed in the reactor effluent after 20 mg l−1 PCP introduction. Sorption and desorption of PCP on the anaerobic sludge granules were all fitted to the Freundlich isotherm
equation. Sorption of PCP was partly irreversible. The Freundlich equation could describe the behavior of PCP amount sorbed
by granular sludge in anaerobic reactor reasonably well. The results demonstrated that the main mechanism leading to removal
of PCP on anaerobic granular sludge was biodegradation, not sorption or volatization. 相似文献