共查询到20条相似文献,搜索用时 15 毫秒
1.
Jesús Torres-Bacete Miguel Arroyo Raquel Torres-Guzmán Isabel de La Mata Carmen Acebal M. Pilar Castillón 《Applied biochemistry and biotechnology》2005,126(2):119-131
The culture medium for Streptomyces lavendulae ATCC 13664 was optimized on a shake-flask scale by using a statistical factorial design for enhanced production of penicillin
acylalse. This extracellularenzyme recently has been reported to bea penicillin Kacylase, presenting also high hydrolytic
activity against penicillin V and other natural aliphatic penicillins such as penicillin K, penicillin F, and penicillin dihydroF,.
The factorial design indicated that the main factors that positively affect penicillin acylase production by S. lavendulae were the concentration of yeast extract and the presence of oligoelements in the fermentation medium, whereas the presence
of olive oil in the medium had no effect on enzyme production. An initial concentration of 2.5% (w/v) yeast extract and 3
μg/mL of CuSO4·5H2O was found to be best for acylase production. In such optimized culture medium, fermentation, of the microorganism yielded
289 IU/L of enzyme in 72 h when employing a volume medium/volume flask ratio of 0.4 and a 300-rpm shaking speed. The presence
of copper, alone and in combination with other metals, stimulated biomass as well as penicillin acylase production. The time
course of penicillin acylase production was also studied in the optimized medium and conditions. Enzyme production showed
catabolite repression by different carbon sources such as glucose, lactose, citrate, glycerol, and glycine. 相似文献
2.
Immobilization of whole-cell penicillin g acylase by entrapping within polymethacrylamide beads 总被引:2,自引:0,他引:2
Liang-Tzung Hsiau Wen-Chien Lee Feng-Sheng Wang 《Applied biochemistry and biotechnology》1997,62(2-3):303-315
Escherichia coli ATCC 11105 containing the periplasmic penicillin G acylase was entrapped within a copolymer of methacrylamide andN,N’- methylenebisacrylamide. A solution of monomer that was made up from methacrylamide andN,N’-methylenebisacrylamide dissolved in buffer was mixed with lyophilized cells and ammonium persulfate. This suspension was
then pumped drop by drop into in soybean oil supplemented with 0.06% (v/v) 3-(dimethylamino)-propionitril. During submerging
in the oil phase, the droplets were hardened and induced to polymerize within the droplets. Particles with a volume ranging
from 0.013–0.017 mL per bead containing a biomass concentration up to 38.0 g/L were prepared. The optimal condition for the
deacylation of penicillin G to 6-aminopencillanic acid (6-APA) catalyzed by the immobilized whole-cell penicillin G acylase
was found to be 45‡C and pH 8.0. Product inhibition of this enzyme by 6-APA could be eliminated by controlling pH value at
8 during the course of penicillin G hydrolysis using a pH-stat. Conversion determined by the pH-stat method were 0.3% higher
than that by p-dimethylaminobenzaldehyde method. Cell concentration in the matrix was found to be an important factor influencing
the maximum velocity and the specific activity retained in the matrix. A kinetic model, in which the mass transfer resistances
as a result of external film mass transfer and pore diffusion were assumed to be negligible, could properly describe the hydrolysis
of penicillin G by the cells entrapped within the polymethacylamide beads. 相似文献
3.
Zeroual Y Kim BS Yang MW Blaghen M Lee KM 《Applied biochemistry and biotechnology》2007,142(3):307-316
Geotrichum sp. strain, which is able to decolorize azo dyes enzymatically, was used in this study for decolorization of synthetics solutions
contaminated by toxic azo dyes orange G, trypan blue, azorubine, and methyl red. The biomass of Geotrichum sp. was immobilized in calcium alginate and polyacrylamide gels and used for the decolorization of tested azo dyes in fluidized
bed bioreactor. The highest specific decolorization rate was obtained when the fungal biomass was entrapped in calcium alginate
beads. Immobilized biomass in calcium alginate continuously decolorized azo dyes after eight repeated batch decolorization
experiments without significant loss of activity whereas polyacrylamide immobilized biomass retained only 10% of its activity
after 4 days of incubation. The effects of some physicochemical parameters such as temperature, pH, and dyes concentration
on decolorization performance of isolated fungal strain were also investigated. 相似文献
4.
The effect of the shear rate on pullulan production from beet molasses by Aureobasidium pullulans P56 in an airlift reactor was investigated. A maximum polysaccharide concentration (18.5 g/L), biomass dry weight (14.0 g/L),
polysaccharide yield (38.5%), and sugar utilization (96%) was achieved at a shear rate of 42 s−1. A. pullulans grown on beet molasses produced a mixture of pullulan and other polysaccharides. The highest value of pullulan proportion
(30% of total polysaccharide) was obtained at a low shear rate (42 s−1). The apparent viscosity of the fermentation broth increased as the shear rate increased up to 42 s−1 and then decreased. On the other hand, the dissolved oxygen concentration and the volumetric mass transfer coefficient increased
with the increase of the shear rate from 21 to 84 s−1. The external addition of L-glutamic acid, olive oil, and Tween-80 improved significantly the production of crude polysaccharide (27.0 g/L), but the
pullulan content of the polysaccharide was low (20%). 相似文献
5.
Paecilomyces marquandii, a phosphate-solubilizing, starch-utilizing filamentous fungus, was immobilized on polyurethane foam (PUF). The immobilized
fungus was applied in a repeated batch (six batches) fermentation process to solubilize Hirapur rock phosphate. The fungus
was immobilized on PUF cubes and was used for phosphate solubilization in shake flask repeated batch cultivations. The fungus
was also immobilized on PUF sheet and utilized in an airlift bioreactor in a repeated batch process. Maximum soluble phosphate
(370 μg/ml) was recorded after third batch with 8 g rock phosphate/l. After 12 days of fermentation, a total production of
1,643 μg phosphate/ml was achieved. 相似文献
6.
Growing cells ofCandida rugosa immobilized in polymethacrylamide-hydrazide and polyurethane foam were employed in fluidized and packed bed reactors, for
discontinuous and continuous fermentations to obtain extracellular lipase. In spite of hydrodynamic problems, fermentation
cultures using polyurethane foam showed higher lipolytic activity than cultures employing polymethacrylamide-hydrazide beads,
which was probably owing to the high immobilized biomass concentration in polyurethane observed by direct microscopy enumeration.
Different oleic acid concentrations were assayed. The maximum level of lipase was achieved at 4 g/L of oleic acid. These results
reaffirm that lipase production is a direct function of cell-substrate contact and that the organic substrate dispersion is
important in this system. 相似文献
7.
José Luis Martínez-Hernández Marco Arnulfo Mata-Gómez Cristóbal Noé Aguilar-González Anna Ilyina 《Applied biochemistry and biotechnology》2010,160(7):2045-2053
The production of extracellular and mycelia-associated penicillin G acylase (maPGA) with Mucor griseocyanus H/55.1.1 by surface-adhesion fermentation using Opuntia imbricata, a cactus, as a natural immobilization support was studied. Enzyme activity to form 6-aminopencillanic acid (6-APA) from
penicillin G was assayed spectrophotometrically. The penicillin G hydrolysis to 6-APA was evaluated at six different times
using PGA samples recovered from the skim milk medium at five different incubation times. Additionally, the effect of varying
the penicillin G substrate concentration level on the PGA enzyme activity was also studied. The maximum reaction rate, V
max, and the Michaelis constant, K
M, were determined using the Michaelis–Menten model. The maximum levels for maPGA and extracellular activity were found to
be 2,126.50 international unit per liter (IU/l; equal to 997.83 IU/g of support) at 48 h and 755.33 IU/l at 60 h, respectively.
Kinetics of biomass production for total biomass showed a maximum growth at 60 h of 3.36 and 2.55 g/l (equal to 0.012 g of
biomass per gram of support) for the immobilized M. griseocyanus biomass. The maPGA was employed for the hydrolysis of penicillin G to obtain 6-APA in a batch reactor. The highest quantity
of 6-APA obtained was 226.16 mg/l after 40-min reaction. The effect of substrate concentration on maPGA activity was evaluated
at different concentrations of penicillin G (0–10 mM). K
M and V
max were determined to be 3.0 × 10−3 M and 4.4 × 10−3 mM/min, respectively. 相似文献
8.
In order to achieve an innovative strategy to renew the biomass of Phanerochaete chrysosporium in an immobilized growth system which can maintain white-rot fungi biomass, a novel knotted cotton-thread carrier was designed
and made. By using a high-speed stirring apparatus under the conditions of 1400 r/min stirring speed for 6 min, mycelia immobilized
on the knotted cotton-thread carriers were exfoliated completely and homogenized to a proper size. Furthermore, the homogenized
mycelia from the immobilized mycelia can resume their growth on the knotted cotton-thread carriers in agitated flask cultures.
The average regrowth biomass on the new carriers and the reused carriers was 0.0171 g/carrier and 0.0314 g/carrier, respectively.
It proves that the knotted cotton-thread carrier performs perfectly in homogening the immobilized mycelia to achieve the biomass
renewal of P. chrysosporium in an immobilized growth system.
Supported by the National Natural Science Foundation of China (Grant No. 206770 33) 相似文献
9.
Lienhardt Jason Schripsema Justin Qureshi Nasib Blaschek Hans P. 《Applied biochemistry and biotechnology》2002,98(1-9):591-598
Acetone butanol ethanol was produced in a continuous immobilized cell (biofilm) plug-flow reactor inoculated with Clostridium beijerinckii BA101. To achieve high reactor productivity, C. beijerinckii BA101 cells were immobilized by adsorption onto clay brick. The continuous plug-flow reactor offers high productivities owing
to reduced butanol inhibition and increased cell concentration. Although high productivity was achieved, it was at the expense
of low sugar utilization (30.3%). To increase sugar utilization, the reactor effluent was recycled. However, this approach
is complicated by butanol toxicity. The effluent was recycled after removal of butanol by pervaporation to reduce butanol
toxicity in the reactor. Recycling of butanolfree effluent resulted in a sugar utilization of 100.7% in addition to high productivity
of 10.2g/(L·h) at a dilution rate of 1.5 h−1. A dilution rate of 2.0h−1 resulted in a reactor productivity of 16.2g/(L·h) and sugar utilization of 101.4%. It is anticipated that this reactor-recovery
system would be economical for butanol production when using C. beijerinckii BA101. 相似文献
10.
Madhavan Nampoothiri K Roopesh K Chacko S Pandey A 《Applied biochemistry and biotechnology》2005,120(2):97-108
Escherichia coli NCIM 2569 was evaluated for its potential for amidase production under submerged fermentation. Among the various amide compounds
screened, maximum substrate specificity and enzyme yield (8.1 U/mL) were obtained by using 1% acetamide. Fermentation was
carried out at 30°C in shake-flask culture under optimized process conditions. A maximum of 0.52 U/mL of intracellular amidase
activity was also obtained from cells incubated for 24 h. Studies were also performed to elucidate the optimal conditions
(gel concentration, initial biomass, curing period of beads, and calcium ion concentration in the production medium) for immobilization
of whole cells. By using E. coli cells entrapped in alginate, a maximum of 6.2 U/mL of enzyme activity was obtained after 12 h of incubation under optimized
conditions. Using the immobilized cells, three repeated batches were carried out successfully, and 85% of the initial enzyme
activity was retained in the second and third batches. The study indicated that the immobilized E. coli cells offered certain advantages such as less time for maximum enzyme production, more stability in the enzyme production
rate, and repeated use of the biocatalyst. 相似文献
11.
Lim JM Kim SW Hwang HJ Joo JH Kim HO Choi JW Yun JW 《Applied biochemistry and biotechnology》2004,119(2):159-170
Optimization of submerged culture conditions for the production of mycelial growth and exopolysaccharides (EPSs) by Collybia maculata was investigated. The optimum temperature and the initial pH for EPS production in a shake-flask culture of C. maculata were found to be 20°C and 5.5, respectively. Among the various medium’s constituents examined, glucose, Martone A-1, K2HPO4, and CaCl2 were the most suitable carbon, nitrogen, and mineral sources for EPS production, respectively. The optimum concentration
of the medium’s ingredients determined using the orthogonal matrix method was as follows: 30 g/L of glucose, 20 g/L of Martone
A-1, 1g/L of K2HPO4, and 1g/L of CaCl2. Under the optimized culture conditions, the maximum concentration of EPSs in a 5-L stirred-tank reactor was 2.4 g/L, which
was approximately five times higher than that in the basal medium. A comparative fermentation result showed that the EPS productivity
in an airlift reactor was higher than that in the stirred-tank reactor despite the lower mycelial growth rate. The specific
productivities and the yield coefficients in the airlift reactor were higher than those in the stirred-tank reactor even though
the volumetric productivities were higher in the stirred-tank reactor than in the airlift reactor. 相似文献
12.
Florbela Carvalheiro Luís C. Duarte Raquel Medeiros Francisco M. Gírio 《Applied biochemistry and biotechnology》2004,115(1-3):1059-1072
Dilute-acid hydrolysis of brewery's spent grain to obtain a pentose-rich fermentable hydrolysate was investigated. The influence
of operational conditions on polysaccharide hydrolysis was assessed by the combined severity parameter (CS) in the range of 1.39–3.06. When the CS increased, the pentose sugars concentration increased to a maximum at a CS of 1.94, whereas the maximum glucose concentration was obtained for a CS of 2.65. The concentrations of furfural, hydroxymethylfurfural (HMF), as well as formic and levulinic acids and total phenolic
compounds increased with severity. Optimum hydrolysis conditions were found at a CS of 1.94 with >95% of feedstock pentose sugars recovered in the monomeric form, together with a low content of furfural, HMF,
acetic and formic acids, and total phenolic compounds. This hydrolysate containing glucose, xylose, and arabinose (ratio 10∶67∶32)
was further supplemented with inorganic salts and vitamins and readily fermented by the yeast Debaryomyces hansenii CCMI 941 without any previous detoxification stage. The yeast was able to consume all sugars furfural, HMF, and acetic acid
with high biomass yield, 0.68C-mol/C-mol, and productivity, 0.92 g/(L·h). Detoxification with activated charcoal resulted
in a similar biomass yield and a slight increase in the volumetric productivity (11%). 相似文献
13.
Whole cells ofBrevibacterium flavum having high fumarase activity were immobilized using K-carrageenan. The reason for the high stability of fumarase activity
of immobilized cells was investigated.
One of main reasons for stabilizing fumarase activity by immobilization using K-carrageenan against organic solvents such
as ethanol and acetone was the lower concentration of these solvents in the carrageenan gel compared with that in outer bulk
solution. The stabilization of fumarase activity in the immobilized cells against protein-denaturing reagents was found to
be related to rheological properties of K-carrageenan gel. Another reason for stabilizing fumarase activity by immobilization
with K-carrageenan was to protect the cells from lysis.
When immobilized cells were freeze-thawed, their fumarase activity increased and operation stability decreased. Therefore,
one reason for the high decay of fumarase activity caused by the freeze-thawing may be a change in the pore size of the K-carrageenan
gel.
Fumarase activity and the operational stability of immobilized cells was found to depend on gelling conditions. Therefore,
the steric structure of the K-carrageenan gel may be related to the decay of fumarase activity. 相似文献
14.
Fernando J. S. Oliveira Francisca P. de França 《Applied biochemistry and biotechnology》2005,122(1-3):581-591
Hexane is a toxic volatile organic compound that is quite abundant in gas emissions from chemical industries and printing
press and painting centers, and it is necessary to treat these airstreams before they discharge into the atmosphere. This
article presents a treatment for hexane-contaminated air in steady-state conditions using an internal-loop airlift bioreactor
inoculated with a Pseudomonas aeruginosa strain. Bioprocesses were conducted at 20-mL/min, a load of 1.26 g/m3 of C6H14, and a temperature of 28°C. The results of hexane removal efficiencies were presented as a function of the inoculum size
(approx 0.07 and 0.2 g/L) and cell reuse. Bioprocess monitoring comprises quantification of the biomass, the surface tension
of the medium, and the hexane concentration in the fermentation medium as well as in the inlet and outlet airstreams. The
steady-state results suggest that the variation in inoculum size from 0.07 to 0.2 g/L promotes hexane abatement from the influent
from 65 to 85%, respectively. Total hydrocarbon removal from the waste gas was achieved during experiments conducted using
reused cells at an initial microbial concentration of 0.2 g/L. 相似文献
15.
介孔材料MCFs的合成及组装青霉素酰化酶的性质研究 总被引:4,自引:0,他引:4
介孔材料由于具有纳米级规则孔道和巨大的比表面积而在催化、吸附及分离等方面存在较大的应用价值.近年来,由介孔分子筛如MCM-41和SBA-15州等组装功能性材料已成为研究的热点.酶作为高效催化剂有许多优点,但在溶液中易失活,使用后无法回收,有的酶在溶液中还存在自水解问题:将酶组装在介孔材料中制成固定化酶则可解决上述问题.目前已成功地将辣根过氧化物酶 相似文献
16.
Urease from pigeonpea (Cajanus cajan L.) was covalently linked to crab shell chitosan beads using glutaraldehyde. The optimum immobilization (64% activity) was
observed at 4°C, with a protein concentration of 0.24 mg/bead and 3% glutaraldehyde. The immobilized enzyme stored in 0.05
M Trisacetate buffer, pH 7.3, at 4°C had a t
1/2 of 110 d. There was practically no leaching of enzyme (<3%) from the immobilized beads in 30 d. The immobilized urease was
used 10 times at an interval of 24 h between each use with 80% residual activity at the end of the period. The chitosan-immobilized
urease showed a significantly higher Michaelis constant (8.3 mM) compared to that of the soluble urease (3.0 mM). Its apparent optimum pH also shifted from 7.3 to 8.5. Immobilized urease showed an optimal temperature of 77°C, compared
with 47°C for the soluble urease. Time-dependent kinetics of the thermal denaturation of immobilized urease was studied and
found to be monophasic in nature compared to biphasic in nature for soluble enzyme. This immobilized urease was used to analyze
blood urea of some of the clinical samples from the clinical pathology laboratories. The results compared favorably with those
obtained by the various chemical/biochemical methods employed in the clinical pathology laboratories. A column packed with
immobilized urease beads was also prepared in a syringe for the regular and continuous monitoring of serum urea concentrations. 相似文献
17.
Júlio C. Santos Ícaro R. G. Pinto Walter Carvalho Ismael M. Mancilha Maria G. A. Felipe Silvio S. Silva 《Applied biochemistry and biotechnology》2005,122(1-3):673-683
Xylose-to-xylitol bioconversion was performed utilizing Candida guillier-mondii immobilized in sugarcane bagasse and cultured in Erlenmeyer flasks using sugarcane bagasse hydrolysate as the source of xylose.
Fermentations were carried out according to a factorial design, and the independent variables considered were treatment, average
diameter, and amount of bagasse used as support for cell immobilization. By increasing the amount of support, the xylitol
yield decreased, whereas the biomass yield increased. The diameter of the support did not influence xylitol production, and
treatment of the bagasse with hexamethylene diamine prior to fermentation resulted in the highest amount of immobilized cells. 相似文献
18.
Dutra JC da C Terzi S Bevilaqua JV Damaso MC Couri S Langone MA Senna LF 《Applied biochemistry and biotechnology》2008,147(1-3):63-75
The aim of this study was to monitor the biomass growth of Aspergillus niger in solid-state fermentation (SSF) for lipase production using digital image processing technique. The strain A. niger 11T53A14 was cultivated in SSF using wheat bran as support, which was enriched with 0.91% (m/v) of ammonium sulfate. The addition of several vegetable oils (castor, soybean, olive, corn, and palm oils) was investigated
to enhance lipase production. The maximum lipase activity was obtained using 2% (m/m) castor oil. In these conditions, the growth was evaluated each 24 h for 5 days by the glycosamine content analysis and digital
image processing. Lipase activity was also determined. The results indicated that the digital image process technique can
be used to monitor biomass growth in a SSF process and to correlate biomass growth and enzyme activity. In addition, the immobilized
esterification lipase activity was determined for the butyl oleate synthesis, with and without 50% v/v hexane, resulting in 650 and 120 U/g, respectively. The enzyme was also used for transesterification of soybean oil and ethanol
with maximum yield of 2.4%, after 30 min of reaction. 相似文献
19.
在内部分散超顺磁性Fe3O4纳米粒子的二乙烯苯交联聚丙烯酸微球表面引入原子转移自由基聚合(ATRP)引发剂,引发聚合向微球表面分别引入P(GMMA-r-DMAEMA-r-GMA)、P(GMMA-r-DMAEMA)和P(GMMA-r-GMA)无规共聚物刷(GMMA为甲基丙烯酸甘油单酯,DMAEMA为甲基丙烯酸-N,N-二甲氨基乙酯,GMA为甲基丙烯酸缩水甘油酯),聚合物刷中GMMA链节的作用是使聚合物刷具有亲水性,DMAEMA引入氨基,GMA引入环氧基.研究了青霉素G酰化酶在这些载体上的固定化和其酶活性.结果表明,同时引入环氧基和氨基的P(GMMA-r-DMAEMA-r-GMA)刷磁性微球固定化青霉素G酰化酶的活性和活性收率都最高,其固定化动力学比只含环氧基P(GMMA-r-GMA)刷磁性微球的好.固定化酶比自由酶更耐热,固定化酶的最佳pH值比自由酶的略高,固定化酶重复使用10次后其活性保留70%. 相似文献
20.
Conidia of Aspergillus niger were immobilized in calcium alginate gel for the production of citric acid. First, the type of the preactivation medium,
together with the preactivation period, was investigated. It was found that A. niger requires a 2-d preactivation period at a 0.05 g/L NH4NO3 concentration. Second, preactivated cells were used to determine the effects of nitrogen concentration and the flow rate
of oxygen and air on the production of citric acid. Maximum citric acid production was attained with medium containing 0.01
g/L of NH4NO3. The rate of citric acid production in the nitrogenous medium was 33% higher when oxygen was used instead of air during the
production phase. This corresponds to an increase of 85% when compared to production when neither oxygen nor air was fed into
the system. In the nonnitrogenous medium citric acid concentration remained similar regardless of the use of air or oxygen.
However, in the nonnitrogenous production medium, citric acid production was not influenced considerably when oxygen was used
instead of air. The advantage of using immobilized cells is that production is achieved easily in the continuous system. Therefore,
citric acid production was also tested using a packed-bed bioreactor, and an increase in productivity by a factor of 22 was
achieved compared to the batch system. 相似文献