共查询到20条相似文献,搜索用时 31 毫秒
1.
A. Krastanov 《Applied microbiology and biotechnology》1997,47(5):476-481
A novel immobilized biocatalyst with invertase activity was prepared by adhesion of yeast cells to wool using glutaraldehyde.
Yeast cells could be immobilized onto wool by treating either the yeast cells or wool or both with glutaraldehyde. Immobilized
cells were not desorbed by washing with 1 M KCl or 0.1 M buffers, pH 3.5–7.5. The biocatalyst shows a maximum enzyme activity
when immobilized at pH 4.2–4.6 and 7.5–8.0. The immobilized biocatalyst was tested in a tubular fixed-bed reactor to investigate
its possible application for continuous full-scale sucrose hydrolysis. The influence of temperature, sugar concentration and
flow rate on the productivity of the reactor and on the specific productivity of the biocatalyst was studied. The system demonstrates
a very good productivity at a temperature of 70 °C and a sugar concentration of 2.0 M. The increase of the volume of the biocatalyst
layer exponentially increases the productivity. The productivity of the immobilized biocatalyst decreases no more than 50%
during 60 days of continuous work at 70 °C and 2.0 M sucrose, but during the first 30 days it remains constant. The cumulative
biocatalyst productivity for 60 days was 4.8 × 103kg inverted sucrose/kg biocatalyst. The biocatalyst was proved to be fully capable of continuous sucrose hydrolysis in fixed-bed
reactors.
Received: 8 November 1996 / Received revision: 31 January 1997 / Accepted: 31 January 1997 相似文献
2.
Doubly entrapped baker's yeast survives during the long-term stereoselective reduction of ethyl 3-oxobutanoate in an organic solvent 总被引:3,自引:0,他引:3
T. Kanda N. Miyata T. Fukui T. Kawamoto A. Tanaka 《Applied microbiology and biotechnology》1998,49(4):377-381
To attain long-term bioreaction in organic solvents with living microorganisms, we tried to protect the microorganisms from
the toxicity of the solvent by immobilization. In this study, baker's yeast, which is not tolerant to organic solvents such
as isooctane, was selected as a model microorganism and the immobilized living yeast cells were examined for activity in the
steroselective reduction of ethyl 3-oxobutanoate to ethyl (S)-3-hydroxybutanoate in isooctane; an activity that correlated well with the viability of the yeast cells. It was found that
double entrapment, that is, further entrapment of calcium-alginate-gel-entrapped cells with a urethane prepolymer, made it
possible for the yeast to remain viable in isooctane, although other conventional immobilization methods, such as single entrapment
using polysaccharide or synthetic resin prepolymers, were insufficient for its protection. Furthermore, doubly entrapped living
yeast cells could carry out the stereoselective reduction in isooctane repeatedly for a long period (more than 1200 h) with
occasional cultivation. Thus, double entrapment enabled a microorganism sensitive to organic solvents to survive over long-term
bioreaction in an organic solvent.
Received: 29 August 1997 / Received last revision: 24 December 1997 / Accepted: 13 January 1998 相似文献
3.
Removal of organic pollutants and of nitrate from wastewater from the dairy industry by denitrification 总被引:3,自引:0,他引:3
The aim of this work was to remove nitrate-N and organic pollutants from wastewater of the dairy industry by denitrification.
An artificially prepared wastewater, containing 250 mg/l nitrate-N and 1.5 g/l whey powder, was completely denitrified with
removal of 90%–93% of the chemical oxygen demand (COD) of the whey powder by suspended or immobilized mixed cultures and by
a suspended or immobilized pure culture that was isolated from the mixed culture inoculum. For the above COD/nitrate-N ratio
of 6:1, the results indicated that the organic compounds of the wastewater served as electron donors for complete denitrification
and that there was no need to add an external carbon source. In batch denitrification assays the suspended or immobilized
mixed cultures proved to be more active and reacted faster than the isolated pure cultures. In continuous denitrification
processes with immobilized pure or mixed cultures, the alginate beads, used for immobilization, were not stable for more than
12 days of incubation. The mixed free cultures removed the nitrate-N and COD continuously with no change of their activity
for at least 15 days at an optimum hydraulic retention time of 0.27 days with a loading rate of 900 mg nitrate-N l−1 day−1.
Received: 13 October 1997 / Received revision: 16 December 1997 / Accepted: 19 December 1997 相似文献
4.
T Roukas 《Journal of industrial microbiology & biotechnology》1999,22(6):617-621
Aureobasidium pullulans P56 was investigated using an adaptation technique and a mixed culture system. The adaptation of A. pullulans and the mixed cultures of A. pullulans and/or Lactobacillus brevisX20, Debaryomyces hansenii 194 and Aspergillus niger did not increase the production of polysaccharide. Enzymic hydrolysis of lactose in deproteinized whey gave a higher polysaccharide
concentration and polysaccharide yield than acidic hydrolysed lactose. Maximum polysaccharide concentration (11.0 ± 0.5 g L−1), biomass dry weight (10.5 ± 0.4 g L−1), polysaccharide yield (47.2 ± 1.8%) and sugar utilization (93.2 ± 2.8%) were achieved using enzyme-hydrolysed whey (pH 6.5)
containing 25 g L−1 lactose and supplemented with K2HPO4 0.5%, L-glutamic acid 1%, olive oil 2.5%, and Tween 80 0.5%. In this case the pullulan content of the crude polysaccharide was 40%.
Received 16 December 1997/ Accepted in revised form 12 March 1999 相似文献
5.
W A Bazaraa M K Hamdy R Toledo 《Journal of industrial microbiology & biotechnology》1998,21(4-5):192-202
Compactin was synthesized by Penicillium cyclopium in submerged as well as in bioreactor systems and assayed spectrophotometrically with a detection limit of 0.5 μg ml−1 solvent. Synthesis in submerged culture was affected by aeration, glucose level, pH, and type and molarity of buffer. Citrate
or succinate (pH 4.0, 0.10 M) in malt glucose peptone broth (MGPB) stimulated cell specialization, sporulation, enhanced compactin
permeation from mycelia and its production (60.05 μg ml−1 after 12 days). Fungal spores, immobilized onto-into loofah sponge, in a bioreactor, using MGPB-citrate as feed stock, resulted
in productivity of 23.04 mg compactin (L−1 h−1) during 50 days operation at 0.45 h−1 dilution rate. Compactin synthesis in the bioreactor was also affected by culture age, substrate, incubation and dilution
rates. Scanning electron micrographs of the loofah sponge, prior to, during and post-spores immobilization showed that loofah
channels served well for fungal support in the bioreactor.
Received 6 October 1997/ Accepted in revised form 2 September 1998 相似文献
6.
T. Matsunaga H. Sudo H. Takemasa Y. Wachi N. Nakamura 《Applied microbiology and biotechnology》1996,45(1-2):24-27
The cyanobacterium, Aphanocapsa halo-phytia MN-11, was immobilized in calcium alginate gel and coated on light-diffusing optical fibers (LDOF) for sulfated extracellular
polysaccharide production. Results indicated that sulfated extracellular polysaccharide production depends on the number of
immobilized cells and the light intensity. In addition, the production rate reached 116.0 mg (mg dry cells)-1 day-1 when the cells that were immobilized on LDOF were incubated under a light intensity of 1380 cd sr m-2 at a cell concentration of 1.0×108 cells/cm3 gel. Cells immobilized on LDOF produced about ten times more sulfated extracellular polysaccharide than those immobilized
in calcium alginate beads only (11.7 mg(mg dry cells)-1 day-1).
Received: 31 March 1995/Revised last revision 12 June 1995/Accepted 26 July 1995 相似文献
7.
Physiological conditions enhancing rhamnose-containing polysaccharide synthesis by Klebsiella I-714 were studied in batch culture (0.3-l and 2-l bioreactors). The four carbon sources tested, sucrose, sorbitol, Neosorb
and Cerelose, allowed exopolysaccharide production. Larger amounts of polymer were produced when high carbon/nitrogen ratios
and complex nitrogen sources were used. Exopolysaccharide synthesis was greatest at 30 °C, which was a suboptimal growth temperature.
A reduction in the phosphate content of the medium enhanced rhamnose-containing polysaccharide production. When the initial
carbon source concentration was augmented, byproducts other than exopolysaccharide were formed. Rhamnose-containing polysaccharide
rheology can be modulated by changing the phosphate content of the medium.
Received: 11 April 1997 / Received revision: 19 June 1997 / Accepted: 23 June 1997 相似文献
8.
Fibrobacter succinogenes S85 cultures that were cellobiose-limited converted cellobiose to succinate and acetate, produced little glucose or cellotriose,
maintained an intracellular ATP concentration of 4.1 mM and a membrane potential of 140 mV for 24 h, did not lyse at a rapid
rate once they had reached stationary phase, and had a most probable number of viable cells that was greater than 106/ml. When the cellobiose concentration was increased 6-fold (5 mM to 30 mM), ammonia was depleted and the cultures left 10 mM
cellobiose. Cultures provided with excess cellobiose produced succinate and acetate while they were growing, but there was
little increase in fermentation acids after the ammonia was depleted and growth ceased. The stationary-phase, cellobiose-excess
cultures had a lysis rate that was 7-fold faster than that of the cellobiose-limited cultures, and the most probable number
was only 3.3 × 103 cells/ml. The stationary-phase, cellobiose-excess cultures had 2.5 times as much cellular polysaccharide as the cellobiose-limited
cultures, but the intracellular ATP and membrane potential were very low (0.1 mM and 40 mV respectively). Methylglyoxal, a
potentially toxic end-product of carbohydrate fermentation, could not be detected, and fresh inocula grew rapidly in spent
medium that was supplemented with additional ammonia. Stationary-phase, cellobiose-excess cultures converted cellobiose to
glucose and cellotriose, but the apparent K
m of cellotriose formation was 15-fold lower than the K
m of glucose production (0.7 mM compared to 10 mM).
Received: 26 June 1997 / Received revision: 12 August 1997 / Accepted: 29 August 1997 相似文献
9.
Bioreactor selection is important for maximising the productivity of recombinant organisms. In this paper a comparison is
made between growth and recombinant protein synthesis in three types of bioreactor containing a marine Vibrio capable of heterologous expression and secretion of the non-toxic B-subunit pentamer of Escherichia coli heat-labile enterotoxin, EtxB. The heterologous gene was located on the plasmid pMMB68. Resistance to carbenicillin was used
to select for plasmid-containing cells. In batch and continuous culture, volumetric productivities were highest when cells
were grown in the presence of carbenicillin. Without antibiotic selection, the highest volumetric productivity (9.4 mg EtxB−1 h−1) was observed in hollow-fibre bioreactors, and the production phase could be maintained for over 50 h. The highest specific
productivity under these conditions was found in batch culture, but the maximal production phase was only of 5 h duration.
In hollow-fibre reactors the type of fibre used significantly affected productivity, both with regards to the maintenance
of reactor integrity and by allowing passage of the recombinant toxoid through the selectively permeable membrane. Where contamination
of the product with carbenicillin is to be avoided, these bioreactors are superior to batch or continuous culture.
Received: 29 January 1997 / Received revision: 9 April 1997 / Accepted: 13 April 1997 相似文献
10.
A Pseudomonas sp. strain NGK 1 (NCIM 5120) was immobilized in various matrices, namely, alginate, agar (1.8 × 1011 cfu g−1 beads) and polyacrylamide (1.6 × 1011 cfu g−1 beads). The degradation of naphthalene was studied, by freely suspended cells (4 × 1010 cfu ml−1) and immobilized cells in batches, with shaken culture and continuous degradation in a packed-bed reactor. Free cells brought
about the complete degradation of 25 mmol naphthalene after 3 days of incubation, whereas, a maximum of 30 mmol naphthalene
was degraded by the bacteria after 3–4 days of incubation with 50 mmol and 75 mmol naphthalene, and no further degradation
was observed even after 15 days of incubation. Alginate-entrapped cells had degraded 25 mmol naphthalene after 3.5 days of
incubation, whereas agar- and polyacrylamide-entrapped cells took 2.5 days; 50 mmol naphthalene was completely degraded by
the immobilized cells after 6–7 days of incubation. Maximum amounts of 55 mmol, 70 mmol and 67 mmol naphthalene were degraded,
from an initial 75 mmol naphthalene, by the alginate-, agar- and polyacrylamide-entrapped cells after 15 days of incubation.
When the cell concentrations were doubled, 25 mmol and 50 mmol naphthalene were degraded after 2 and 5.5 days of incubation
by the immobilized cells. Complete degradation of 75 mmol naphthalene occurred after 10 days incubation with agar- and polyacrylamide-entrapped␣cells,
whereas only 60 mmol naphthalene was degraded by alginate-entrapped cells after 15 days of␣incubation. Further, with 25 mmol
naphthalene, alginate-, agar- and polyacrylamide-entrapped cells (1.8 × 1011 cfu g−1 beads) could be reused 18, 12 and 23 times respectively. During continuous degradation in a packed-bed reactor, 80 mmol naphthalene
100 ml−1 h−1 was degraded by alginate- and polyacrylamide-entrapped cells whereas 80 mmol naphthalene 125 ml−1␣h−1 was degraded by agar-entrapped cells.
Received: 21 October 1997 / Received revision: 15 January 1998 / Accepted: 18 January 1998 相似文献
11.
Gisela S. Alvarez María L. Foglia Guillermo J. Copello Martín F. Desimone Luis E. Diaz 《Applied microbiology and biotechnology》2009,82(4):639-646
Immobilized bacteria are being extensively used for metabolite production, biocatalysts, and biosensor construction. However,
long-term viability and metabolic activity of entrapped bacteria is affected by several conditions such as their physiological
state, the presence of high-osmolarity environments, porous structure and shrinkage of the matrix. The aim of this work was
to evaluate the effect of various parameters on bacteria immobilized in sol–gel-derived silica matrices. With this purpose,
we evaluated the stress of immobilization over bacteria cultures obtained from different growing states, the effect of cell
density and bacteria capability to proliferate inside matrices. Best results to attain longer preservation times were obtained
when we immobilized suspensions with an optimized bacterial number of 1 × 107 cfu/gel in the presence of LB medium using aqueous silica precursors. Furthermore, the impact of osmotic stress with the
subsequent intracellular trehalose accumulation and the addition of osmolites were investigated. Shorter preservation times
were found for bacteria immobilized in the presence of osmolites while trehalose accumulation in stressed cells did not produce
changes on entrapped bacteria viability. Finally, nutrient addition in silica matrices was studied indicating that the presence
of a carbon source without the simultaneous addition of nitrogen was detrimental for immobilized E. coli. However, when both carbon and nitrogen sources were present, bacteria were able to survive longer periods of time. 相似文献
12.
K D Chapatwala G R V Babu O K Vijaya K P Kumar J H Wolfram 《Journal of industrial microbiology & biotechnology》1998,20(1):28-33
Pseudomonas putida utilizes cyanide as the sole source of carbon and nitrogen. Agar, alginate, and carrageenan were screened as the encapsulating
matrices for P. putida. Alginate-immobilized cells of P. putida degraded sodium cyanide (NaCN) more efficiently than non-immobilized cells or cells immobilized in agar or carrageenan. The
end products of biodegradation of cyanide were identified as ammonia (NH3) and carbon dioxide (CO2). These products changed the medium pH. In bioreactors, the rate of cyanide degradation increased with an increase in the
rate of aeration. Maximum utilization of cyanide was observed at 200 ml min−1 of aeration. Immobilized cells of P. putida degraded cyanides, cyanates and thiocyanates to NH3 and CO2. Use of Na[14C]-CN showed that 70% of carbon of Na[14C]-CN was converted into 14CO2 and only 10% was associated with the cell biomass. The substrate-dependent kinetics indicated that the K
m and V
max values of P. putida for the substrate, NaCN were 14 mM and 29 nmol of oxygen consumed mg protein−1 min−1 respectively.
Received 29 January 1996/ Accepted in revised form 19 September 1997 相似文献
13.
Hydrogen production with high yield and high evolution rate by self-flocculated cells of Enterobacter aerogenes in a packed-bed reactor 总被引:6,自引:1,他引:5
M. A. Rachman Y. Nakashimada T. Kakizono N. Nishio 《Applied microbiology and biotechnology》1998,49(4):450-454
Continuous hydrogen gas evolution by self-flocculated cells of Enterobacter aerogenes, a natural isolate HU-101 and its mutant AY-2, was performed in a packed-bed reactor under glucose-limiting conditions in
a minimal medium. The flocs that formed during the continuous culture were retained even when the dilution rate was increased
to 0.9 h−1. The H2 production rate increased linearly with increases in the dilution rate up to 0.67 h−1, giving maximum H2 production rates of 31 and 58 mmol l−1 h−1 in HU-101 and AY-2 respectively, at a dilution rate of more than 0.67 h−1. The molar H2 yield from glucose in AY-2 was maintained at about 1.1 at dilution rates between 0.08 h−1 and 0.67 h−1, but it decreased rapidly at dilution rates more than 0.8 h−1.
Received: 27 August 1997 / Received revision: 11 November 1997 / Accepted: 14 December 1997 相似文献
14.
The physiological roles of omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid have been investigated in detail
and microbial strains producing these polyunsaturated fatty acids have been characterised. It has recently been suggested
that docosapentaenoic acid may have an important role, especially in infant nutrition, and that its positive health effects
have been overlooked. Docosapentaenoic acid (C22:5, ω-3) production by a strain of Pythium acanthicum ATCC 18660 was thus investigated. Optimum conditions for growth of P. acanthicum ATCC 18660 and docosapentaenoic acid production were: pH 6.0, temperature 20°C and incubation time, 10 days. Among different
saccharides and complex nitrogen sources tested, glucose and sodium glutamate were preferred carbon and nitrogen sources,
respectively. Maximum biomass content (10.4 g L−1) and docosapentaenoic acid yield (49.9 mg L−1) were obtained in 10 days. An increase in docosapentaenoic acid volumetric yields to 108–110 mg L−1 was obtained when linseed oil was used to supplement glucose or soy flour-containing medium. Batch feeding of additional
glucose or linseed oil further enhanced the docosapentaenoic acid volumetric yield to 132 mg L−1 and 125 mg L−1, respectively, in 14 days. The specific production of docosapentaenoic acid in preliminary experiments ranged from 1.0–5.0 mg g−1 biomass. As conditions were optimised, docosapentaenoic acid specific production titers were generally in the range of 4.0–5.5 mg g−1 and increases in docosapentaenoic acid volumetric production could be attributed to increased biomass production. The limited
improvement obtained by modifying culture conditions indicates that increasing volumetric yields of docosapentaenoic acid
by modifying culture conditions appears to represent a significant barrier to commercialisation of such a process and suggests
a more fundamental manipulation of metabolism and physiology is required.
Received 06 November 1997/ Accepted in revised form 10 January 1998 相似文献
15.
The agaric basidiomycete Clitocybula dusenii was used for the production of the extracellular ligninolytic enzyme, manganese (Mn) peroxidase. An immobilization technique
is described using cellulose and polypropylene as carrier for the fungal mycelium. High amounts of Mn peroxidase were obtained
with agitated cultures of immobilized fungus (up to 3,000 U l−1) while the biomass was recovered and used for further production cycles. Purification of Mn peroxidase revealed the existence
of two forms: MnP1 (molecular mass 43 kDa, pI 4.5) and MnP2 (42 kDa, pI 3.8).
Received: 30 July 1999 / Received revision: 1 December 1999 / Accepted: 3 December 1999 相似文献
16.
Mesophilic and thermophilic anaerobic digestion of source-sorted organic wastes: effect of ammonia on glucose degradation and methane production 总被引:5,自引:0,他引:5
The wet organic fraction of household wastes was digested anaerobically at 37 °C and 55 °C. At both temperatures the volatile
solids loading was increased from 1 g l−1 day−1 to 9.65 g l−1 day−1, by reducing the nominal hydraulic retention time from 93 days to 19 days. The volatile solids removal in the reactors at
both temperatures for the same loading rates was in a similar range and was still 65% at 19 days hydraulic retention time.
Although more biogas was produced in the thermophilic reactor, the energy conservation in methane was slightly lower, because
of a lower methane content, compared to the biogas of the mesophilic reactor. The slightly lower amount of energy conserved
in the methane of the thermophilic digester was presumably balanced by the hydrogen that escaped into the gas phase and thus
was no longer available for methanogenesis. In the thermophilic process, 1.4 g/l ammonia was released, whereas in the mesophilic
process only 1 g/l ammonia was generated, presumably from protein degradation. Inhibition studies of methane production and
glucose fermentation revealed a K
i (50%) of 3 g/l and 3.7 g/l ammonia (equivalent to 0.22 g/l and 0.28 g/l free NH3) at 37 °C and a K
i (50%) of 3.5 g/l and 3.4 g/l ammonia (equivalent to 0.69 g/l and 0.68 g/l free NH3) at 55 °C. This indicated that the thermophilic flora tolerated at least twice as much of free NH3 than the mesophilic flora and, furthermore, that the thermophilic flora was able to degrade more protein. The apparent ammonia
concentrations in the mesophilic and in the thermophilic biowaste reactor were low enough not to inhibit glucose fermentation
and methane production of either process significantly, but may have been high enough to inhibit protein degradation. The
data indicated either that the mesophilic and thermophilic protein degraders revealed a different sensitivity towards free
ammonia or that the mesophilic population contained less versatile protein degraders, leaving more protein undegraded.
Received: 26 March 1997 / Received revision: 13 May 1997 / Accepted: 19 May 1997 相似文献
17.
Pseudomonas aeruginosa UW-1 produced 17–24 g L−1 rhamnolipid in vegetable oil-containing media in shake flask cultures in 13 days. In time course studies of growth and
rhamnolipid production in a salts medium containing 6% canola oil, total bacterial count reached 2.6 × 1010 CFU ml−1 after 48 h and a maximum rhamnolipid yield of 24.3 g L−1 was obtained after 9 days. Rhamnolipid components were purified and separated by chloroform-methanol extraction and TLC
chromatography. The major rhamnolipid components were characterised as L-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate and
L-rhamnosyl-L-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate by nuclear magnetic resonance and mass spectrometry. The components
were separated preparatively by silica gel column chromatography. The recovered monorhamnosyl fraction contained no dirhamnosyl
moiety while the recovered dirhamnosyl fraction contained 5% of the monorhamnosyl moiety when analyzed by HPLC. The ratio
of mono- to dirhamnosyl components produced by P. aeruginosa UW-1 was determined by HPLC to be 4 : 1 by weight. Purified mono- and dirhamnosyl components had the same CMC value of
40 μg ml−1 and decreased the surface tension of water to 27.7 and 30.4 dynes cm−1, respectively.
Received 04 April 1997/ Accepted in revised form 15 July 1997 相似文献
18.
Effects of ethanol concentration and stripping temperature on continuous fermentation rate 总被引:1,自引:0,他引:1
F. Taylor M. J. Kurantz N. Goldberg J. C. Craig Jr. 《Applied microbiology and biotechnology》1997,48(3):311-316
The operation of a pilot plant consisting of a 14-l fermentor, 10-cm packed column and condenser for continuous fermentation
and stripping of ethanol was stable for more than 100 days. The feed consisted of a non-sterile solution of 560 g/l glucose
with 100 g/l corn steep water. Fouling of the packing in the column with attached growth of yeast cells was controlled by
in situ washing at intervals of 3–6 days. A computer simulation of the pilot plant was developed and used to analyze the data.
The productivity of the continuous fermentor varied from 14 g ethanol to 17 g ethanol l−1 h−1. The yield was equal to the maximum theoretically possible: 0.51 g ethanol/g glucose consumed. Results are fit to linear
models for the effects of ethanol concentration on specific growth rate and cell yield, and for the effect of stripping temperature
on specific growth rate.
Received: 16 October 1996 / Received revision: 3 January 1997 / Accepted: 24 January 1997 相似文献
19.
J L Schwartz E B Ferrari J Terracciano J Troyanovich I Gunnarsson J Wright-Minogue J W Chen A D Kwong 《Journal of industrial microbiology & biotechnology》1997,19(2):87-91
A gene expression system using recombinant Autographa californica nuclear polyhedrosis virus (baculovirus) and Sf-9 cells has been scaled up to the 10-L tank level and shown to be capable
of producing herpes simplex virus (HSV) protease in serum-free media. High densities of Spodoptera frugiperda (Sf-9) cells were achieved by modifying two 10-L Biolafitte fermenters specifically for insect cell growth. The existing
Rushton impellers were replaced by marine impellers to reduce shear and the aeration system was modified to allow external
addition of air/O2 mixtures at low flow rates through either the sparge line or into the head space of the fermenter. To inoculate the tanks,
Sf-9 cells were adapted to grow to high cell densities (6–10 × 106 cells ml−1) in shake flasks in serum-free media. With these procedures, cell densities of 5 × 106 cells ml−1 were routinely achieved in the 10-L tanks. These cells were readily infected with recombinant baculovirus expressing the
247-amino acid catalytic domain of the HSV-1 strain 17 protease UL26 gene as a glutathione-S-transferase (GST) fusion protein (GST-247). Three days after infection at a multiplicity of infection (MOI) of 3 pfu cell−1, the GST-247 fusion protein was purified from a cytoplasmic lysate by Glutathione Sepharose 4-B affinity chromatography
with reproducible yields of 11–38 mg L−1 of recombinant protein and ≥ 90% purity. Maximum production of this protein was observed at a cell density of 5.0 × 106 cells ml−1.
Received 09 December 1996/ Accepted in revised form 13 April 1997 相似文献
20.
Low-temperature bioremediation of a waste water contaminated with anionic surfactants and fuel oil 总被引:7,自引:0,他引:7
We conducted a laboratory study at 10 °C on the biological decontamination of the waste water from a garage and car-wash
that was contaminated with anionic surfactants (57 mg l−1) and fuel oil (184 mg hydrocarbons l−1). The indigenous microorganisms degraded both contaminants efficiently after biostimu- lation by an inorganic nutrient supply.
After 7 days at 10 °C, the residual contaminations were 11 mg anionic surfactants l−1 and 26 mg hydrocarbons l−1. After 35 days, only the anionic surfactants had been further reduced to 3 mg l−1. Bioaugmentation of the unfertilized waste water with a cold-adapted inoculum, able to degrade both hydrocarbons (diesel
oil) and anionic surfactants (sodium dodecyl sulphate), resulted in a significant increase of the hydrocarbon biodegradation
during the first 3 days of decontamination, whereas biodegradation of anionic surfactants was inhibited during the first 21 days
following inoculation. Bioaugmentation of the nutrient-amended waste water was without any effect.
Received: 14 November 1997 / Accepted: 29 November 1997 相似文献