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1.
Kuyukina MS Ivshina IB Rubtsova EV Ivanov RV Lozinskiĭ VI 《Prikladnaia biokhimiia i mikrobiologiia》2011,47(2):176-182
Adsorption of Rhodococcus ruber cells on columns with polyacrylamide cryogel (CryoPAAG) partially hydrophobized by different quantities (0.2, 1, and 5 mol %) of chemically grafted n-dodecane residues has been studied. The adsorption capacity (1.1 x 10(9) cells/g) of gel carrier for rhodococcal cells and the optimal content (1 mol %) of hydrophobizing groups were determined. The respirometric method showed the high catalytic activity and functional stability of immobilized bacterial cells. Respiratory activity of immobilized rhodococci in the presence of a model mixture of oil hydrocarbons exceeded the respective parameter for free cells by 12-17%. Viability of rhodococcal cells adsorptionally fixed in hydrophobized cryoPAAG was maintained at a level of 93-95% after a half-year period of storage. The results may be used for development of immobilized biocatalyst for directed transformation of hydrocarbon compounds and biological purification of oil-polluted water. 相似文献
2.
The impact of insoluble phosphorus such as aluminum and rock phosphate on alkaline phosphatase activity of polyurethane foam
immobilized cyanobacteria was assessed. Polyurethane foam immobilized Nodularia recorded the highest alkaline phosphatase activity of 9.04 (m. mol p-nitrophenol released h–1 mg–1 protein) in vitro. A higher concentration of aluminum phosphate was recorded a 25% reduction in alkaline phosphatase activity,
ammonia content, and available phosphorus in culture filtrate of polyurethane foam immobilized cyanobacteria. In general,
immobilized cyanobacteria exhibited a higher alkaline phosphatase activity in rock phosphate than aluminum phosphate. 相似文献
3.
Cultures able to dechlorinate cis-1,2-dichloroethene (cDCE) were selected with ethene (3–20%, v/v) as the sole source of carbon and energy. One mixed culture (K20) could degrade
cDCE (400 μmol l–1) or vinyl chloride (100 μmol l–1) in the presence of ethene (≤ 80 μmol l–1 and ≤ 210 μmol l–1, respectively). This culture consists of at least five bacterial strains. All five strains were able to degrade cDCE cometabolically in pure culture. The mixed culture K20 was highly tolerant against cDCE (up to 6 mmol l–1 in the liquid phase). Degradation of cDCE (200 μmol l–1) was not affected by the presence of trichloroethene (100 μmol l–1) or tetrachloroethene (100 μmol l–1). Transformation yields (Ty, defined as unit mass of chloroethene degraded per unit mass of ethene consumed) of the mixed culture K20 were relatively
high (0.51 and 0.61 for cDCE and vinyl chloride, respectively). The yield for cDCE with ethene as auxiliary substrate was ninefold higher than any values reported with methane or methane/formate as auxiliary
substrate. The viability of the cells of the mixed culture K20 (0.3 mg of cells ml–1) was unaffected by the transformation of ≤ 200 μmol l–1
cDCE in 300 min.
Received: 9 March 1999 / Accepted: 21 July 1999 相似文献
4.
A novel third-generation biosensor for hydrogen peroxide (H2O2) has been constructed based on horseradish peroxidase (HRP) immobilized by the sol–gel (SG) technology on carbon nanotube
(CNT)-modified electrode. CNT has good promotion effects on the direct electron transfer between HRP and the electrode surface
and the SG network provides a biocompatible microenvironment for enzyme. The immobilized HRP retained its bioelectrocatalytic
activity for the reduction of hydrogen peroxide and can respond to the change of concentration of H2O2 rapidly. The heterogeneous electron transfer rate constant was evaluated to be 2.8 ± 0.4 s−1. The amperometric response to H2O2 shows a linear relation in the range from 0.5 to 300 μmol l−1 and a detection limit of 0.1 μmol l−1 (S/N = 3). The K
Mapp value of HRP immobilized on the electrode surface was found to be 1.35 mmol l−1. The biosensor exhibited high sensitivity, rapid response and excellent long-term stability. 相似文献
5.
A Bacillus sp., capable of degrading chloroform, was immobilized in calcium alginate. The beads in 20 g alginate l−1 (about 2 × 108 cells/bead) could be re-used nine times for degradation of chloroform at 40 μM. The immobilized cells had a higher range
of tolerance (pH 6.5–9 and 20–41°C) than free cells (pH 7–8.5 and 28–32°C). At 5 g alginate l−1, leakage of the cells from the beads was 0.51 mg dry wt ml−1. This species is the first reported Bacillus that can degrade chloroform as the sole carbon source. 相似文献
6.
A J Kreuzman R L Hodges J R Swartling T E Pohl S K Ghag P J Baker D McGilvray W K Yeh 《Journal of industrial microbiology & biotechnology》2000,24(3):173-180
Aspergillus nidulans produces echinocandin B, a neutral lipopeptide. A deacylase from Actinoplanes utahensis catalyzes cleavage of the linoleoyl group from echinocandin B, a key step in generating a potential antifungal agent. Virtually
all (99.8%) deacylase activity was cell-associated. The deacylase was salt-solubilized, heat-treated and purified to apparent
homogeneity by a 3-step chromatographic procedure. The enzyme was a heterodimer consisting of 63- and 18-to-20-kDa subunit,
optimally active at pH 6.0, and at 60°C with salt. The K
m of the deacylase for echinocandin B was 50 μM and its V
max was 14.6 μmol cyclic hexapeptide min−1 mg−1protein. The substrate specificity of the enzyme was broad with respect to both acyl and cyclic peptide analogues of echinocandin
B. The two deacylase subunit genes were cloned and over-expressed in Streptomyces lividans. The recombinant deacylase was purified from the culture filtrate to apparent homogeneity by a 1-step chromatographic procedure.
Using the recombinant deacylase, an enzymatic deacylation of immobilized echinocandin B resulted in the generation of cyclic
hexapeptide at gram-level. Journal of Industrial Microbiology & Biotechnology (2000) 24, 173–180.
Received 24 August 1999/ Accepted in revised form 23 November 1999 相似文献
7.
Abrunhosa L Costa M Areias F Venâncio A Proença F 《Journal of industrial microbiology & biotechnology》2007,34(12):787-792
The activity on Aspergillus spp. growth and on ochratoxin A production of two novel chromene dimers (3) was evaluated. The results of the bioassays indicate that the chromene dimer 3a inhibited mycelia growth by approximately 50% (EC50) at 140.1 μmol L−1 for A. niger, 384.2 μmol L−1 for A. carbonarius, 69.1 μmol L−1 for A. alliaceus and 559.1 μmol L−1 for A. ochraceus. When applied at concentrations of 2 mmol L−1, 3a totally inhibited the growth of all Aspergillus spp. tested. Furthermore, ochratoxin A production by A. alliaceus was reduced by about 94% with a 200 μmol L−1 solution of this compound. A moderate inhibitory effect was observed for the analogous structure 3b on ochratoxin A production but not in mycelia growth. No inhibition was registered for compounds 2a and 2b, used as synthetic precursors of the dimeric species 3. 相似文献
8.
Tetrahydrofolate was shown to function as a methyl acceptor in the anaerobic demethylation of dimethylsulfoniopropionate
to methylthiopropionate in cell extracts of the sulfate-reducing bacterium strain WN. Dimethylsulfoniopropionate-dependent
activities were 0.56 μmol methyltetrahydrofolate min–1 (mg protein)–1 and were higher than required to explain the growth rate of strain WN on dimethylsulfoniopropionate. The reaction did not
require ATP or reductive activation by titanium(III)-nitrilotriacetic acid. Preincubation of the extract under air significantly
decreased the activity (35% loss in 3 h). Three other dimethylsulfoniopropionate-demethylating sulfate reducers, Desulfobacterium niacini, Desulfobacterium vacuolatum, and Desulfobacterium strain PM4, had dimethylsulfoniopropionate:tetrahydrofolate methyltransferase activities of 0.16, 0.05, and 0.24 μmol min–1 (mg protein)–1, respectively. No methyltransferase activity to tetrahydrofolate was found with betaine as a substrate, not even in extracts
of betaine-grown cells of these sulfate reducers. Dimethylsulfoniopropionate demethylation in cell extracts of strain WN was
completely inhibited by 0.5 mM propyl iodide; in the light, the inhibition was far less strong, indicating involvement of
a corrinoid-dependent methyltransferase.
Received: 24 June 1997 / Accepted: 29 August 1997 相似文献
9.
N Kiran Sree M Sridhar K Suresh I M Banat L Venkateswar Rao 《Journal of industrial microbiology & biotechnology》2000,24(3):222-226
A repeated batch fermentation system was used to produce ethanol using an osmotolerant Saccharomyces cerevisiae (VS3) immobilized in calcium alginate beads. For comparison free cells were also used to produce ethanol by repeated batch fermentation.
Fermentation was carried for six cycles with 125, 250 or 500 beads using 150, 200 or 250 g glucose L−1 at 30°C. The maximum amount of ethanol produced by immobilized VS3 using 150 g L−1 glucose was only 44 g L−1 after 48 h, while the amount of ethanol produced by free cells in the first cycle was 72 g L−1. However in subsequent fed batch cultures more ethanol was produced by immobilized cells compared to free cells. The amount
of ethanol produced by free cells decreased from 72 g L−1 to 25 g L−1 after the fourth cycle, while that of immobilized cells increased from 44 to 72 g L−1. The maximum amount of ethanol produced by immobilized VS3 cells using 150, 200 and 250 g glucose L−1 was 72.5, 93 and 87 g ethanol L−1 at 30°C. Journal of Industrial Microbiology & Biotechnology (2000) 24, 222–226.
Received 16 September 1999/ Accepted in revised form 22 December 1999 相似文献
10.
Efremenko E Votchitseva Y Plieva F Galaev I Mattiasson B 《Applied microbiology and biotechnology》2006,70(5):558-563
Organophosphate hydrolase containing hexahistidine tag at the N-terminus of recombinant protein (His6-OPH) and expressed in Escherichia coli cells was purified using supermacroporous polyacrylamide-based monolith columns with immobilized metal affinity matrices
[Me2+-iminodiacetic acid (IDA)–polyacrylamide cryogel (PAA) and Me2+-N,N,N’-tris (carboxymethyl) ethylendiamine (TED)–PAA]. Enzyme preparation with 50% purity was obtained by direct chromatography
of nonclarified cell homogenate, whereas the combination of addition of 10 mM imidazole to buffers for cell sonication and
sample loading, the use of precolumn with IDA–PAA matrix noncharged with metal ions, and the application of high flow rate
provided the 99% purity of enzyme isolated directly from crude cell homogenate. Co2+-IDA–PAA provided the highest level of selectivity for His6-OPH. Comparative analysis of purification using Co2+-IDA–PAA and Ni-nitrilotriacetic acid–agarose showed obvious advantages of the former in process time, specific activity of
purified enzyme, and simplicity of adsorbent regeneration. 相似文献
11.
Phytase activity in rabbit cecal bacteria 总被引:1,自引:0,他引:1
The presence of phytase activity was demonstrated in 26 strains of rabbit cecal bacteria. In 25 strains a low phytase activity,
0.10–0.62 μmol phosphate released per min per mg protein, was found. High activity (2.61 μmol/min per mg protein) was found
in the strain PP2 identified as Enterococcus hirae. Phytase activity was cell-associated, being higher in the cell extract than in the cell walls. Extracellular phytase activity
and cell-associated phosphatase activity were not detected. Phytase activity was optimal around pH 5.0, which is below the
physiological cecal pH range. The K
m determined using the Lineweaver-Burk plot was 0.19 μmol/mL. Cations Fe3+, Cu2+ and Zn2+ at 0.5 mmol/L decreased phytase activity in sonicated cells of E. hirae by 99.4, 90.7 and 96.5 %, respectively. In contrast, Mg2+ increased activity by 11.0 %. Characteristics of E. hirae phytase (pH optimum, K
m, cation sensitivity) were similar to those of other bacterial phytases reported in the literature. Other bacteria with a
high phytase activity may be present in the rabbit cecum but remain to be identified. 相似文献
12.
M. S. Kadam A. B. Chaudhari S. B. Chincholkar 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2012,6(3):249-254
Optical fluorescence-quenching-based biosensing cell is described and optimization of covalent binding of highly selective natural iron-chelating peptide secreted by bacteria is suggested. Pyoverdin biosynthesized by Pseudomonas monteilii and having 70% iron chelating activity was immobilized on amino alkylated controlled pore glass (CPG) and cross-linked with glutaraldehyde (2.5%, 28°C, 30 min). The pyoverdin-CPG immobilization was confirmed using fluorescence microscopic images (excitation range, 465–495 nm) for bright green fluorescence and by FTIR spectrum stretching at 3406.4 cm−1 for amino group. The pyoverdin loading capacity of activated CPG matrix was 25 mg g−1 of CPG and its rinsing analysis (leaking profile of the immobilized peptide vs. washing) detected negligible (2–3 μg) pyoverdin in the second wash. 相似文献
13.
Use of immobilized bacteria to treat industrial wastewater containing a chlorinated pyridinol 总被引:1,自引:0,他引:1
Pseudomonas sp. strain M285 immobilized on diatomaceous earth beads was used to remove 3,5,6-trichloro-2-pyridinol (TCP) from industrial
wastewater. Batch studies showed that immobilized Pseudomonas sp. strain M285 mineralized [2,6-14C]TCP rapidly; about 75% of the initial radioactivity was recovered as 14CO2. Transformation of TCP was inhibited by high concentrations of salt, and addition of osmoprotectants (proline and betaine
at 1 mM) did not reduce the adverse effect of salt. TCP-containing wastewater (60–140 mg/l) was passed through columns containing
immobilized Pseudomonas sp. strain M285 at increasing flow rates and increasing TCP concentrations; TCP removal of 80%–100% was achieved. Addition
of nutrients, such as glucose and yeast extract, retarded TCP degradation. Growing cell cultures were found to be better inocula
for immobilization than resting cells.
Received: 5 February 1996 / Received last revision: 12 August 1996 / Accepted: 24 August 1996 相似文献
14.
Callus induction and thallus regeneration from callus of phycocolloid yielding seaweeds from the Indian coast 总被引:1,自引:0,他引:1
The tissue culture of phycocolloid yielding seaweeds included preparation of axenic explants, callus induction, subculture
of excised callus and regeneration of plantlets from pigmented callus in the laboratory. Treatment of algal material with
0.1–0.5% detergent for 10 min and 1–2% betadine for 1–5 min and 3–5% antibiotic treatment for 48–72 h successively enabled
viable axenic explants to be obtained as high as 60% for Gracilaria
corticata, Sargassum
tenerrimum and Turbinaria
conoides and 10% for Hypnea
musciformis. Callus induction was more conspicuous in T. conoides than in the other three species investigated. Of the irradiances investigated, 30 μmol photons m−2 s−1 produced calluses in as many as 40% explants in G. corticata and T. conoides and 10% in H. musciformis and S. tenerrimum. The explants cultured at 5 and 70 μmol photons m−2 s−1 did not produce any callus in all the species studied except for H. musciformis in which 10% explants developed callus at 5 μmol photons m−2 s−1. Most of the species investigated showed uniseriate filamentous Type of growths and buds from cut ends and from all over
the surface of explants. Nevertheless, T. conoides had three Types of callus developments, namely (1) uniseriate filamentous Type of outgrowths from the centre of the cut end
of explant, (2) bubbly Type of callus and (3) club-shaped callus clumps. The subculture of T. conoides callus embedded in 0.4% agar produced two Types of filamentous growth, namely filiform (with elongated cells) and moniliform
filaments (with round cells) in the 2 months period after inoculation. Further, friable callus with loose cells was also found
associated with excised callus. The moniliform filaments showed prolific growth of micro-colonies resembling to somatic embryo-like
growth which, in liquid cultures, differentiated and developed into propagules with deformed shoots and distinct rhizoids.
The shoots of these propagules remained stunted with abnormal leaf stalks without forming triangular shaped leaves as the
parental plant and rhizoids had prolific growth in the laboratory cultures. The excised callus of G. corticata continued to grow when transferred to liquid cultures and showed differentiation of new shoots within 10 days. The shoots
grew to a maximum length of 5–6 cm in the 2 months period in aerated cultures in the laboratory.
Dedicated to the memory of Late Dr. Rangarajan. 相似文献
15.
Hydrogenase was solubilized from the cytoplasmic membrane fraction of betaine-grown Sporomusa sphaeroides, and the enzyme was purified under oxic conditions. The oxygen-sensitive enzyme was partially reactivated under reducing conditions,
resulting in a maximal activity of 19.8 μmol H2 oxidized min–1 (mg protein)–1 with benzyl viologen as electron acceptor and an apparent K
m
value for H2 of 341 μM. The molecular mass of the native protein estimated by native PAGE and gel filtration was 122 and 130 kDa, respectively.
SDS-PAGE revealed two polypeptides with molecular masses of 65 and 37 kDa, present in a 1:1 ratio. The native protein contained
15.6 ± 1.7 mol Fe, 11.4 ± 1.4 mol S2–, and 0.6 mol Ni per mol enzyme. The hydrogenase coupled with viologen dyes, but not with other various artificial electron
carriers, FAD, FMN, or NAD(P)+. The amino acid sequence of the N-termini of the subunits showed a high degree of similarity to eubacterial membrane-bound
uptake hydrogenases. Washed membranes catalyzed a H2-dependent cytochrome b reduction at a rate of 0.18 nmol min–1 (mg protein)–1.
Received: 7 September 1995 / Accepted: 4 December 1995 相似文献
16.
Purification, immobilization and characterization of linoleic acid isomerase on modified palygorskite 总被引:2,自引:0,他引:2
Linoleic acid isomerase from Lactobacillus delbrueckii subsp. bulgaricus 1.1480 was purified by DEAE ion-exchange chromatography and gel filtration chromatography. An overall 5.1% yield and purification
of 93-fold were obtained. The molecular weight of the purified protein was ~41 kDa which was analyzed by SDS-PAGE. The purified
enzyme was immobilized on palygorskite modified with 3-aminopropyltriethoxysilane. The immobilized enzyme showed an activity
of 82 U/g. The optimal temperature and pH for the activity of the free enzyme were 30 °C and pH 6.5, respectively; whereas
those for the immobilized enzyme were 35 °C and pH 7.0, respectively. The immobilized enzyme was more stable than the free
enzyme at 30–60 °C, and the operational stability result showed that more than 85% of its initial activity was retained after
incubation for 3 h. The K
m and V
max values of the immobilized enzyme were found to be 0.0619 mmol l−1 and 0.147 mmol h−1 mg−1, respectively. The immobilized enzyme had high operational stability and retained high enzymatic activity after seven cycles
of reuse at 37 °C. 相似文献
17.
Solovchenko A Khozin-Goldberg I Recht L Boussiba S 《Marine biotechnology (New York, N.Y.)》2011,13(3):527-535
In order to develop a practical approach for fast and non-destructive assay of total fatty acid (TFA) and pigments in the
biomass of the marine microalga Nannochloropsis sp. changes in TFA, chlorophyll, and carotenoid contents were monitored in parallel with the cell suspension absorbance.
The experiments were conducted with the cultures grown under normal (complete nutrient f/2 medium at 75 μmol PAR photons/(m2 s)) or stressful (nitrogen-lacking media at 350 μmol PAR photons/(m2 s)) conditions. The reliable measurement of the cell suspension absorbance using a spectrophotometer without integrating
sphere was achieved by deposition of cells on glass–fiber filters in the chlorophyll content range of 3–13 mg/L. Under stressful
conditions, a 30–50% decline in biomass and chlorophyll, retention of carotenoids and a build-up of TFA (15–45 % of dry weight)
were recorded. Spectral regions sensitive to widely ranging changes in carotenoid-to-chlorophyll ratio and correlated changes
of TFA content were revealed. Employing the tight inter-correlation of stress-induced changes in lipid metabolism and rearrangement
of the pigment apparatus, the spectral indices were constructed for non-destructive assessment of carotenoid-to-chlorophyll
ratio (range 0.3–0.6; root mean square error (RMSE) = 0.03; r
2 = 0.93) as well as TFA content of Nannochloropsis sp. biomass (range 5.0–45%; RMSE = 3.23 %; r
2 = 0.89) in the broad band 400–550 nm normalized to that in chlorophyll absorption band (centered at 678 nm). The findings
are discussed in the context of real-time monitoring of the TFA accumulation by Nannochloropsis cultures under stressful conditions. 相似文献
18.
Ten accessions belonging to the Brassica oleracea subspecies alba and rubra, and to B. oleracea var. sabauda were used in this study. Protoplasts were isolated from leaves and hypocotyls of in vitro grown plants. The influence of selected factors on the yield, viability, and mitotic activity of protoplasts immobilized
in calcium alginate layers was investigated. The efficiency of protoplast isolation from hypocotyls was lower (0.7 ± 0.1 × 106 ml−1) than for protoplasts isolated from leaf mesophyll tissue (2 ± 0.1 × 106 ml−1). High (70–90%) viabilities of immobilized protoplasts were recorded, independent of the explant sources. The highest proportion
of protoplasts undergoing divisions was noted for cv. Reball F1, both from mesophyll (29.8 ± 2.2%) and hypocotyl (17.5 ± 0.3%)
tissues. Developed colonies of callus tissue were subjected to regeneration and as a result plants from six accessions were
obtained. 相似文献
19.
Ethanol production from starch by immobilized Aspergillus awamori and Saccharomyces pastorianus using cellulose carriers 总被引:1,自引:0,他引:1
Fujii N Oki T Sakurai A Suye S Sakakibara M 《Journal of industrial microbiology & biotechnology》2001,27(1):52-57
A simultaneous saccharification and fermentation (SSF) process was investigated to produce ethanol using two kinds of cellulose
carriers that were respectively suitable for immobilization of Aspergillus awamori and Saccharomyces pastorianus. The maximum ethanol concentration attained by the batch operation was 25.5 g l−1. Under suitable conditions, both cellulose carriers with immobilized cells could be reused efficiently for three cycles.
The total amount of ethanol production was 66.0 g (per 1 l working volume) after the repeated operation. Ethanol productivity
mainly depends on a saccharification process. There is a limit in durability in the repeated batch operation, and it is important
to maintain high activity of the fungus in order to produce ethanol efficiently. Journal of Industrial Microbiology & Biotechnology (2001) 27, 52–57.
Received 11 December 2000/ Accepted in revised form 02 June 2001 相似文献
20.
B B Nepple J Kessi R Bachofen 《Journal of industrial microbiology & biotechnology》2000,25(4):198-203
Rhodobacter sphaeroides grew in the presence of up to 43 μM chromate and reduced hexavalent chromium to the trivalent form under both aerobic and
anaerobic conditions. Reduced chromium remained in the external medium. Reductase activity was present in cells of R. sphaeroides independent of whether chromate was present or not in the growth medium. The reducing activity was found in the cytoplasmic
cell fraction and was dependent on NADH. The chromate-reducing enzyme was purified by anion exchange, hydroxyapatite and hydrophobic
interaction chromatography, and gel filtration. The molecular weight of the enzyme was 42 kDa as determined by gel filtration.
The optimum of the reaction is at pH 7.0 and 30°C. The enzyme activity showed a hyperbolic dependence on the concentrations
of both substrates, NADH and chromate, with a maximum velocity at 0.15 mM NADH. A K
m of 15±1.3 μM CrO4
2− and a V
max of 420±50 μmol min−1 mg protein−1 was determined for the enzyme isolated from anaerobically grown cells and 29±6.4 μM CrO4
2− and 100±9.6 μmol CrO4
2− min−1 mg protein−1 for the one from aerobically grown ones. Journal of Industrial Microbiology & Biotechnology (2000) 25, 198–203.
Received 05 January 2000/ Accepted in revised form 27 May 2000 相似文献