共查询到20条相似文献,搜索用时 31 毫秒
1.
Andrea Bauer Norman Layh Christoph Syldatk Andrew Willetts 《Biotechnology letters》1996,18(3):343-348
Summary Resting cells of Rhodococcus sp. ATCC 39484 were immobilized in polyvinyl alcohol (PVA). The PVA-beads showed nitrile-hydrolysing activity with propionitrile as a model substrate. Drying of the beads resulted in a loss of weight of 85 %. Re-swollen beads showed no loss in activity. In a continuously-operated fixed-bed bioreactor, beads were able to convert substrate concentrations up to 100 mM. 相似文献
2.
Enhancement and stabilization of the production of glucoamylase by immobilized cells of Aureobasidium pullulans in a fluidized-bed reactor 总被引:1,自引:0,他引:1
Federico Federici Maurizio Petruccioli Martin W. Miller 《Applied microbiology and biotechnology》1990,33(4):407-409
Summary Glucoamylase production by Aureobasidium pollulans A-124 was compared in free-living cells, cells immobilized in calcium alginate gel beads aerated on a rotary shaker (agitation rate 150 rpm), and immobilized cells aerated in an air bubble column reactor. Fermentation conditions in the bioreactor were established for bead concentration, substrate (starch) concentration, calcium chloride addition to the fermentation medium, and rate of aeration. Production of glucoamylase was optimized at approximately 1.5 units of enzyme activity/ml medium in the bioreactor under the following conditions: aeration rate, 2.0 vol air per working volume of the bioreactor (280 ml) per minute; gel bead concentration, 30% of the working volume; substrate (starch) concentration, at 0.3% (w/v); addition of calcium chloride to the medium at a final concentration of 0.01 M. Productivity levels were stabilized through the equivalent of ten batches of medium with the original inoculum of immobilized beads.
Offprint requests to: M. Petruccioli 相似文献
3.
B. Bugarski G. A. King G. Jovanovic A. J. Daugulis M. F. A. Goosen 《Applied microbiology and biotechnology》1989,30(3):264-269
Summary The performance of an external loop air-lift bioreactor was investigated by assessing the inter-relationships between various hydrodynamic properties and mass transfer. The feasibility of using this bioreactor for the production of monoclonal antibodies by mouse hybridoma cells immobilized in calcium alginate gel beads and alginate/poly-l-lysine microcapsules was also examined. When the superficial gas velocity, V
g
, in the 300 ml reactor was varied from 2 to 36 cm/min, the average liquid velocity increased from 3 to 14 cm/sec, the gas hold-up rose from 0.2 to 3.0%, and the oxygen mass transfer coefficient, k
L
a, increased from 2.5 to 18.1 h-1. A minimum liquid velocity of 4 cm/s was required to maintain alginate gel beads (1000 m diameter, occupying 3% of reactor volume) in suspension. Batch culture of hybridoma cells immobilized in alginate beads followed logarithmic growth, reaching a concentration of 4×107 cells/ml beads after 11 days. Significant antibody production did not occur until day 9 into the culture, reaching a value of 100 g/ml of medium at day 11. On the other hand, bioreactor studies with encapsulated hybridoma cells gave monoclonal antibody concentrations of up to 800 g/ml capsules (the antibody being retained within the semipermeable capsule) and maximum cell densities of 2×108 cells/ml capsule at day 11. The volumetric productivities of the alginate gel immobilized cell system and the encapsulated cell system were 9 and 3 g antibody per ml of reactor volume per day, respectively. The main advantage of the bioreactor system is its simple design, since no mechanical input is required to vary the hydrodynamic properties. 相似文献
4.
Jun Huang Le-he Mei Hong Wu Dong-qiang Lin 《World journal of microbiology & biotechnology》2007,23(6):865-871
On an industrial scale, the production of γ-aminobutyric acid (GABA) from the cheaper sodium L-glutamate (L-MSG) is a valuable
process. By entrapping Lactobacillus brevis cells with higher glutamate decarboxylase (GAD) activity into Ca-alginate gel beads, the biotransformation conditions of
L-MSG to GABA were optimized with the immobilized cells. The cells obtained from a 60-h culture broth showed the highest biotransformation
efficiency from L-MSG to GABA. The optimal cell density in gel beads, reaction pH and temperature were 11.2 g dry cell weight
(DCW) l−1, 4.4 and 40°C respectively. The thermal stability of immobilized cells was significantly higher than free cells. Under the
optimized reaction conditions, the yield of GABA reached above 90% during the initial five batches and the yield still remained
56% in the tenth batch. Continuous production of GABA was realized with a higher yield by incorporating cell re-cultivation
using the packed bed reactor. 相似文献
5.
Sanjay Chauhan Anuradha Nichkawade M.R.S. Iyengar Bharat B. Chattoo 《Current microbiology》1998,37(3):186-190
Aerobic cultures of an actinomycete were found to produce penicillin V acylase (PVA) (PA, EC-3.5.1.11) extracellularly. The
presence of L-2-3 diamino-propionic acid in cell wall and formation of sclerotia on culture media led to its identification
as Chainia, a sclerotial Streptomyces. Partially purified acylase was adsorbed on kieselguhr and entrapped in polyacrylamide gel. The immobilized preparation proved
effective with respect to retention of enzyme and enzyme activity even after 15 successful cycles. The pH optimum for crude
enzyme was in the range of pH 7.5–8.0, and for the (NH4)2 SO4 fraction it was pH 8.5. The immobilized enzyme showed maximal activity at pH 9.5. The optimum temperature for acylase activity
was at 55°C. The crude enzyme, ammonium sulfate fraction, and immobilized enzyme showed K
m
value for penicillin V of 6.13 mM, 14.3 mM, and 17.1 mM, respectively.
Received: 11 December 1997 / Accepted: 9 April 1998 相似文献
6.
Pseudomonas GM3, a highly efficient strain in cleavage of azo bonds of synthetic dyes under anoxic conditions, was immobilized via adsorption on two types of carriers, porous glass beads and solid PVA particles. The cells were cultivated in a nutrient medium, adsorbed on sterile carriers, stabilized as biofilms in repeated batch cultures, and introduced into a chemostat activated sludge reactor for augmented decolourization. The microbial cells were quickly adsorbed and fixed on the PVA surface, compared to a slow and linear immobilization on the glass surface. The porous structure of glass beads provided shelter for the embedded cells, giving a high biomass loading or thick biofilm (13.3 mg VS ml?1 carrier) in comparison with PVA particles (4.8 mg VS ml?1 carrier), but the mass transfer of substrate in the biofilm became a significant limiting factor in the thicker biofilms (effectiveness factor η = 0.31). The microbial decolourization rate per volume of carriers was 0.15 and 0.17 mg dye ml?1 of glass beads and PVA particles, respectively. In augmented decomposition of a recalcitrant azo dye (60 mg l?1), the immobilized Pseudomonas cells in porous glass beads gave a stable decolourization efficiency (80 - 81%), but cells fixed on solid PVA particles showed an initial high colour removal of 90% which then declined to a stable removal efficiency of 81%. In both cases, the colour removal efficiency of the chemostat bioreactor was increased from < 10% by an activated sludge to ~80% by the augmented system. 相似文献
7.
R. J. Manolov 《World journal of microbiology & biotechnology》1993,9(1):29-33
Several fungal strains ofAspergillus andPenicillium were immobilized by cryopolymerization in polyvinyl alcohol cryogel beads.Aspergillus clavatus was the best producer of extracellular ribonuclease. Enzyme productivity and growth of free and immobilized cells in shake flasks and agitated bioreactor were studied. Ribonuclease production and growth behaviour depended on concentrations of glucose, peptone and soybean in the culture medium. Enzyme production was influenced by agitation and aeration intensity. In repeated batch, shake-flask cultures, the immobilized cells showed 2 to 3.5 times higher enzyme activity than free cells. The optimal conditions in a bioreactor were at 150 rev/min agitation speed and 0.5 vol/vol.min aeration. Enzyme productivity of immobilized cells (237 units/g dry mycelium.h) was 2.1 times higher than the productivity of free cells in a bioreactor, and 2.3 times higher than that of a shake-flask culture.R.J. Manolov is with the Institute of Microbiology, Department of Enzymes, Bulgarian Academy of Sciences, Georgy Bonchev Street 26, 1113 Sofia, Bulgaria. 相似文献
8.
A new method for immobilization of acetylcholinesterase (AChE) to alginate gel beads by activating the carbonyl groups of
alginate using carbodiimide coupling agent has been successfully developed. Maximum reaction rate (V
max) and Michaelis–Menten constant (K
m) were determined for the free and binary immobilized enzyme. The effects of pH, temperature, storage stability, reuse number
and thermal stability on the free and immobilized AChE were also investigated. For the free and binary immobilized enzyme
on the Ca–alginate gel beads, optimum pH values were found to be 7 and 8, respectively. Optimum temperatures for the free
and immobilized enzyme were observed to be 30 and 35 °C, respectively. Upon 60 days of storage the preserved activity of free
and immobilized enzyme were found as 4 and 68%, respectively. In addition, reuse number, and thermal stability of the free
AChE were increased by as a result of binary immobilization. 相似文献
9.
Alberto Domínguez Jose Gómez Miriam Lorenzo Ángeles Sanromán 《World journal of microbiology & biotechnology》2007,23(3):367-373
In the present paper the effect of adding veratryl alcohol and copper sulphate on laccase activity production by Trametes versicolor immobilized into alginate beads has been investigated. Employing copper sulphate as laccase inducer or supplementing the
culture medium with veratryl alcohol, led to maximum values of laccase activity. However, the highest laccase activity (around
4,000 U l−1) was obtained in cultures simultaneously supplemented with copper sulphate (3 mM) and veratryl alcohol (20 mM). These values
implied a considerable enhancement in relation to␣control cultures without any inducer (around 200 U l−1).
The production of laccase by immobilized T. versicolor in a 2-l airlift bioreactor with the optimized inducer has been evaluated. Laccase activities around 1,500 U l−1 were attained. The bioreactor operated for 44 days without operational problems and the bioparticles (fungus grows in alginate
beads) maintained their shape throughout the fermentation. Moreover, the extracellular liquid obtained was studied in terms
of pH and temperature activity and stability. On the other hand, anthracene was added in two-repeated batches in order to
determine the efficiency of this process to degrade pollutants. Near complete degradation was reached in both batches. Moreover,
in vitro degradation of several polycyclic aromatic hydrocarbons by crude laccase was also performed. 相似文献
10.
Guitta Younes Annick M. Breton Janine Guespin-Michel 《Applied microbiology and biotechnology》1987,25(6):507-512
Summary Several strains of the protein-secreting, Gram negative bacterium Myxococcus xanthus were immobilized in carrageenan beads and the production of extracellular proteins was followed.The extracellular proteolytic activity was enhanced and concentrated in the beads. In contrast, the amount of total protein secreted by the cells was not modified by immobilization, but it was also retained and concentrated in the beads, the more, the harder the gel. The amount of slime produced by the cells did not seem to influence protein retention.Foreign proteins expressed from genes cloned in Myxococcus xanthus chromosome can be secreted into the medium by immobilized recombinant strains. A polygalacturonate lyase, expressed from the pelC gene from Erwinia chrysanthemi was only detectable outside of the beads. The pH 2.5 acid phosphatase expressed from the appA gene from Escherichia coli was secreted by immobilized cells at the same rate than did the free cells. It was predominantly found in the medium outside of the beads which represented a first purification and facilitated the continuous production of this protein by immobilized recombinant cells packed in a reactor. 相似文献
11.
Saccharomyces cerevisiae CY phytase-producing cells were immobilized in calcium alginate beads and used for the degradation of phylate. The maximum
activity and immobilization yield of the immobilized phytase reached 280 mU/g-bead and 43%, respectively. The optimal pH of
the immobilized cell phytase was not different from that of the free cells. However, the optimum temperature for the immobilized
phytase was 50°C, which was 10°C higher than that of the free cells; pH and thermal stability were enhanced as a consequence
of immobilization. Using the immobilized phytase, phytate was degraded in a stirred tank bioreactor. Phytate degradation,
both in a buffer solution and in soybean-curd whey mixture, showed very similar trends. At an enzyme dosage of 93.9 mU/g-phytate,
half of the phytate was degraded after 1 h of hydrolysis. The operational stability of the immobilized beads was examined
with repeated batchwise operations. Based on 50% conversion of the phytate and five times of reuse of the immobilized beads,
the specific degradation (g phytate/g dry cell weight) for the immobilized phytase increased 170% compared to that of the
free phytase. 相似文献
12.
Sirisansaneeyakul S Luangpipat T Vanichsriratana W Srinophakun T Chen HH Chisti Y 《Journal of industrial microbiology & biotechnology》2007,34(5):381-391
Production of lactic acid from glucose by immobilized cells of Lactococcus lactis IO-1 was investigated using cells that had been immobilized by either entrapment in beads of alginate or encapsulation in
microcapsules of alginate membrane. The fermentation process was optimized in shake flasks using the Taguchi method and then
further assessed in a production bioreactor. The bioreactor consisted of a packed bed of immobilized cells and its operation
involved recycling of the broth through the bed. Both batch and continuous modes of operation of the reactor were investigated.
Microencapsulation proved to be the better method of immobilization. For microencapsulated cells at immobilized cell concentration
of 5.3 g l−1, the optimal production medium had the following initial concentrations of nutrients (g l−1): glucose 45, yeast extract 10, beef extract 10, peptone 7.5 and calcium chloride 10 at an initial pH of 6.85. Under these
conditions, at 37 °C, the volumetric productivity of lactic acid in shake flasks was 1.8 g l−1 h−1. Use of a packed bed of encapsulated cells with recycle of the broth through the bed, increased the volumetric productivity
to 4.5 g l−1 h−1. The packed bed could be used in repeated batch runs to produce lactic acid. 相似文献
13.
Wael A. Bazaraa Mostafa K. Hamdy 《Journal of industrial microbiology & biotechnology》1989,4(4):267-274
Summary ImmobilizedArthrobacter cells (NRRL-B-3728) were used for continuous isomerization of glucose to fructose in a bioreactor system. The system utilized stationary phase (55h) cells (2.2×109 CFU/ml saline) immobilized onto K-carrageenan (3% w/v) beads [cells were heated at 65°C for 10 min to inactivate endogenous proteolytic enzymes]. Immobilized-cell preparations were hardened using three different glutaraldehyde systems. Glutaraldehyde (0.2 M) treated-immobilized cells (pH 7.0, 5°C for 30 min) exhibited good gel strength and high glucose isomerase activities. Maximal bioreactor isomerization of 44% was achieved when a buffered feedstock containing 40% glucose was fed into the column (60°C) at a flow rate of 0.2 ml/min. The biological half-life of glucose isomerase activities in this system was 400 h. Scanning electron microscopy revealed large numbers of cells distributed within the beads. A thin layer surrounding the beads following glutaraldehyde treatment was mainly due to cross-linking reactions between cell proteins and glutaraldehyde. This layer prevented leaking of cells during continuous isomerization reaction. 相似文献
14.
A copper [Cu(II)]-accumulating strain, Pseudomonas putida II-11, isolated from electroplating effluent removed a significantly high amount of Cu(II) from growth medium and buffer. A laboratory-scale fixed bed reactor with cells of P. putida II-11 immobilized in polyacrylamide gel was constructed. The adsorption of Cu(II) by the immobilized cells was pH-dependent. Maximum removal of Cu(II) by the immobilized cells was at pH 8.0. The presence of Cr(IV), Ni(II) and Zn(II) did not significantly inhibit Cu(II) uptake whereas the presence of Pb(II) reduced Cu(II) uptake by fivefold. The presence of borate, carbonate, chloride and sulphate did not significantly inhibit Cu(II) uptake. The Cu(II) removal capacity of the bioreactor with immobilized cells did not change significantly when operated at retention times greater than 3 min. More than 90% of Cu(II) adsorbed on immobilized cells could be recovered by eluting with 0.1 m HCl. The bioreactor could be used for at least five loading-elution cycles without loss of Cu(II) removal capacity. The feasibility of using this bioreactor to remove and recover Cu(II) from electroplating effluent is discussed.
Correspondence to: P. K. Wong 相似文献
15.
Papagianni M Joshi N Moo-Young M 《Journal of industrial microbiology & biotechnology》2002,29(5):259-263
The effects of cell immobilization on the secretion of extracellular proteases and glucoamylase production by Aspergillus niger were investigated under a variety of immobilization techniques and culture conditions. Immobilization was achieved by means
of cell attachment on metal surfaces or spore entrapment and subsequent growth on porous Celite beads. Free-suspension cultures
were compared with immobilized mycelium under culture conditions that included growth in shake flasks and an airlift bioreactor.
Cell attachment on metal surfaces minimized the secretion of proteases while enhancing glucoamylase production by the fungus.
Growth on Celite beads in shake-flask cultures reduced the specific activity of the secreted proteases from 128 to 61 U g−1, while glucoamylase specific activity increased from 205 to 350 U g−1. The effect was more pronounced in bioreactor cultures. A reduction of six orders of magnitude in protease specific activities
was observed when the fungus grew immobilized on a rolled metal screen, which served as the draft tube of an airlift bioreactor.
Received 29 October 2001/ Accepted in revised form 14 June 2002 相似文献
16.
Jean-Christophe Vuillemard Sylvie Terré Stéphane Benoit Jean Amiot 《Applied microbiology and biotechnology》1988,27(5-6):423-431
Summary
Serratia marcescens and Myxococcus xanthus cells were immobilized in calcium alginate gel beads. Immobilization under various conditions had no effect on the extracellular proteolytic activity of S. marcescens cells. Protease production seemed rather to depend on the free cells in the medium. However, the stability over time of enzyme production was enhanced, as immobilization increased protease production half-life from 5 to 12 days. On the other hand, Myxococcus xanthus produced proteases inside the gel beads which could diffuse into the medium. The proteolytic activity increased as a function of the initial cell content of the beads and of the bead inoculum. Compared to free cells, immobilized cells of Myxococcus xanthus could produce 8 times more proteolytic activity, with a very low free-cell concentration in the medium. 相似文献
17.
Hydrodynamic characteristics of immobilized cell beads in a liquid-solid fluidized-bed bioreactor 总被引:2,自引:0,他引:2
This study examined the hydrodynamic characteristics of a liquid-solid fluidized-bed bioreactor using elastic particles (PVA gel beads) of various diameters as carriers. The drag coefficient-Reynolds number, velocity-voidage, and expansion index-Reynolds number relationships observed during fluidization of PVA gel beads in a fluidized bed in our experiments were compared with the published results. Predictions made from previous correlations were examined with our new experimental findings, revealing the inadequacy of most of these correlations. Thus, new correlations describing the above-mentioned relationships are suggested. The drag coefficient of immobilized cell beads is larger than that of free cell ones at the same Reynolds number because the surface of the immobilized cell beads is rougher. For multiparticle systems, the correction factor, f(epsilon), is a function of the falling gel bead properties (Reynolds number) as well as the fluidized gel bead properties (Archimedes number), and depend strongly on the bed voidage (epsilon). A new simple relation was developed to predict easily the epsilon value from 0.5-0.9 at 4,986 < A(r) < 40,745 or 34 < Re(t) < 186. For all the immobilized cell beads used in this study, the prediction error of the bed voidage was less than 5% at epsilon > 0.5. The prediction equations in this study can be further applied to analyzing the hydrodynamic characteristics of a fluidized-bed reactor using similar entrapped elastic particles as carriers. 相似文献
18.
Coprinus cinereus, which was able to decolorize the anthraquinone dye Cibacron Blue 3G-A (CB) enzymatically, was used as a biocatalyst for
the decolorization of synthetic solutions containing this reactive dye. Coprinus cinereus was immobilized in both calcium alginate and polyacrylamide gels, and was used for the decolorization of CB from synthetic
water by using a fluidized bed bioreactor. The highest specific decolorization rate was obtained when Coprinus cinereus was entrapped in calcium alginate beads, and was of about 3.84 mg g−1 h−1 with a 50% conversion time (t
1/2) of about 2.60 h. Moreover, immobilized fungal biomass in calcium alginate continuously decolorized CB even after 7 repeated
experiments without significant loss of activity, while polyacrylamide-immobilized fungal biomass retained only 67% of its
original activity. The effects of some physicochemical parameters such as temperature, pH and dye concentration on decolorization
performance of isolated fungal strain were also investigated. 相似文献
19.
Yu-Chih Chang Roch-Chui Yu Hsin-Yi Yang Cheng-Chun Chou 《World journal of microbiology & biotechnology》2005,21(6-7):1129-1134
Summary Some physical factors including initial pH of medium, cultivation temperature and shaking speed as well as reuse affecting
the production of cholesterol oxidase (CholOx) in reactors containing calcium alginate-immobilized cells of Rhodococcus equi No. 23 were investigated. Results revealed that the free cells showed the maximum CholOx in the culture with an initial pH
of 5.0, while culture inoculated with immobilized cells exhibited a broad pH range, 6.0–9.0, for maximum CholOx production.
The immobilized and free cells produced the maximum CholOx in the culture incubated at 30 and 25°C, respectively. The CholOx
production decreased upon increasing the cultivation temperature. Increasing CholOx activity was also noted for both immobilized
and free cells of R. equi No. 23 in the culture with increasing shaking speed. Under the optimal culture conditions, that were established, a higher
maximum CholOx production of 0.94 unit/ml was found for immobilized R. equi No. 23 compared to that of 0.84 unit/ml for free cells after 48 h of cultivation. Furthermore, no gel leakage was noted after
re-use of the calcium alginate-immobilized R. equi No. 23 for seven consecutive 48 h batch culture. The CholOx production in the seventh cycle was about 60.4% of that obtained
in the first cycle. 相似文献
20.
Vellore Sunder Avinash Palna Dinesh Chauhan Shraddha Gaikwad 《Preparative biochemistry & biotechnology》2017,47(1):52-57
The production of 6-aminopenicillanic acid (6-APA) is a key step in the manufacture of semisynthetic antibiotics in the pharmaceutical industry. The penicillin G acylase from Escherichia coli has long been utilized for this purpose. However, the use of penicillin V acylases (PVA) presents some advantages including better stability and higher conversion rates. The industrial application of PVAs has so far been limited due to the nonavailability of suitable bacterial strains and cost issues. In this study, whole-cell immobilization of a recombinant PVA enzyme from Pectobacterium atrosepticum expressed in E. coli was performed. Membrane permeabilization with detergent was used to enhance the cell-bound PVA activity, and the cells were encapsulated in calcium alginate beads and cross-linked with glutaraldehyde. Optimization of parameters for the biotransformation by immobilized cells showed that full conversion of pen V to 6-APA could be achieved within 1?hr at pH 5.0 and 35°C, till 4% (w/v) concentration of the substrate. The beads could be stored for 28 days at 4°C with minimal loss in activity and were reusable up to 10?cycles with 1-hr hardening in CaCl2 between each cycle. The high enzyme productivity of the PVA enzyme system makes a promising case for its application for 6-APA production in the industry. 相似文献