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1.
Thermomucor indicae-seudaticae was immobilized in alginate, κ-carrageenan, agarose, agar, polyacrylamide and loofah (Luffa cylindrica) sponge (as such or coated with alginate/starch/Emerson YpSs agar), and used for the production of glucoamylase in submerged
fermentation. The mycelium developed from alginate-immobilized sporangiospores secreted higher glucoamylase titres (22.7 U ml−1) than those immobilized in other gel matrices and the freely growing mycelial pellets (18.5 U ml−1). Loofah network provided a good support for mycelial growth, but the enzyme production was lower than that attained with
alginate beads. Glucoamylase production increased with inoculum density and the optimum levels were achieved when 40 calcium
alginate beads (∼5 × 106 immobilized spores) were used to inoculate 50 ml production medium. The alginate bead inoculum displayed high storage stability
at 4°C and produced comparable enzyme titres up to 120 days. The glucoamylase production by hyphae emerged from the immobilized
sporangiospores was almost stable over eight batches of repeated fermentation. Scanning electron micrographs of alginate beads,
after batch fermentation, revealed extensive mycelial growth inside and around the beads. 相似文献
2.
E Selmer-Olsen T Sørhaug S-E Birkeland R Pehrson 《Journal of industrial microbiology & biotechnology》1999,23(2):79-85
Lactobacillus helveticus CNRZ 303 entrapped in Ca-alginate gel beads was investigated for improved survival and stability during fluidized-bed drying,
storage and rehydration. Addition of protective solutes was very important. Studies of the conditions showed that inactivation
of entrapped L. helveticus started when the water content exceeded 0.3–0.4 g H2O (g dry wt)−1 for adonitol, glycerol and reconstituted non fat milk solids (NFSM). With Ringer’s solution (control) and betaine, the fall
in viability was evident above 1 g H2O (g dry wt)−1. Drying down to 0.2 g H2O (g dry wt)−1 required the removal of 98.5–98.9% of the water. The best survival rate with the least injured cells among survivors was
experienced with adonitol and NFMS, respectively, 71% and 57% (compared to the initial) immediately after dehydration. Adonitol
and NFMS were also best for survival during storage. The highest cell recovery was obtained by rehydrating the cells in cheese
whey permeate between 20–30°C done at pH 6.0–7.0, satisfying the demands for cell survival, repair and slow swelling (adaptions).
Received 04 January 1999/ Accepted in revised form 29 April 1999 相似文献
3.
Two plant growth-promoting bacteria, Bacillus subtilis and Pseudomonas corrugata, immobilized in a sodium alginate based formulation were evaluated for their survival, viability and plant growth-promoting
ability after 3 years of storage at 4 °C. Populations of both of the bacterial isolates recovered from the immobilized sodium
alginate beads were in the order of 108 cfu g−1. The plant-based bioassay indicated that the plant growth promotion ability of both of the bacterial isolates was equal to
those of fresh broth-based formulations. The bacterial isolates retained the root colonization, and antifungal and enzyme
activities in the alginate-based formulation during storage. 相似文献
4.
Om Prakash Mahe Talat S. H. Hasan Rajesh K. Pandey 《Biotechnology and Bioprocess Engineering》2008,13(2):210-216
Enzyme urease is extracted from the discarded seeds of pumpkin. Urease was purified to apparent homogeneity (5.2 fold) by
heat treatment at 48 ± 1°C and gel filtration through Sephadex G-200. Effect of model metal ions on the activity of the homogeneous
enzyme preparation (sp. activity 353 U/mg protein, A280/A260 = 1.12) of soluble as well as immobilized enzyme was investigated. The soluble and immobilized urease has been used for the
quantitative estimation of general water pollution with heavy metal ions like Hg2+, Cu2+, Cd2+, and Co2+. The measurements of the urease residual activity have been carried out in tris-acetate buffer after pre-incubation of model
metal salt. The inhibition was found to be biphasic with an initial rapid loss of activity and remainder in slow phase of
10∼15 min. The immobilization was done in 3.5% alginate beads leading to 86% of entrapment. There was no leaching of the enzyme
over a period of 15 days at 4°C. The beads were fairly stable up to 50°C and exhibited activity even at −10°C. The inhibition
by these ions was non-competitive and irreversible, hence could not be restored by dialysis. Based on the values of inhibition
constant Ki the heavy-metal ions were found to inhibit urease in the following order Hg2+ > Cu2+ > Cd2+ > Co2+. 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.
The effect of ANG II on pHi, [Ca2+]i and cell volume was investigated in T84 cells, a cell line originated from colon epithelium, using the probes BCECF-AM, Fluo
4-AM and acridine orange, respectively. The recovery rate of pHi via the Na+/H+ exchanger was examined in the first 2 min following the acidification of pHi with a NH4Cl pulse. In the control situation, the pHi recovery rate was 0.118 ± 0.001 (n = 52) pH units/min and ANG II (10−12 M or 10−9 M) increased this value (by 106% or 32%, respectively) but ANG II (10−7 M) decreased it to 47%. The control [Ca2+]i was 99 ± 4 (n = 45) nM and ANG II increased this value in a dose-dependent manner. The ANG II effects on cell volume were minor and late
and should not interfere in the measurements of pHi recovery and [Ca2+]i. To document the signaling pathways in the hormonal effects we used: Staurosporine (a PKC inhibitor), W13 (a calcium-dependent
calmodulin antagonist), H89 (a PKA inhibitor) or Econazole (an inhibitor of cytochrome P450 epoxygenase). Our results indicate
that the biphasic effect of ANG II on Na+/H+ exchanger is a cAMP-independent mechanism and is the result of: 1) stimulation of the exchanger by PKC signaling pathway
activation (at 10−12 – 10−7 M ANG II) and by increases of [Ca2+]i in the lower range (at 10−12 M ANG II) and 2) inhibition of the exchanger at high [Ca2+]i levels (at 10−9 – 10−7 M ANG II) through cytochrome P450 epoxygenase-dependent metabolites of the arachidonic acid signaling pathway. 相似文献
7.
N. Marignetti M. D. Fumi A. Silva G. Battistotti M. Pomini O. Colagrande 《Biotechnology Techniques》1997,11(1):7-8
The geometry of calcium alginate gel spheres is studied by fractal interpretation for prediction of number of cells to be
immobilized. For alginate concentrations from 1 to 5% the simulated results are of 6.65×108, 1.44×108 and 5.27×107 N cell mL−1 for respectively 1.5, 2.5 and 3.5 mm gel sphere diameters. Simulated data are compared with those resulting from literature
and particularly with experimental trials where from 107 to 108 N cell mL−1, in 2% alginate beads with a diameter of 1.5 mm, is able to fulfil mechanical and swelling characteristics of alginate gel
beads besides to supply good oxygenation. 相似文献
8.
Kar S Mandal A Mohapatra PK Samanta S Pati BR Mondal KC 《Journal of industrial microbiology & biotechnology》2008,35(4):245-249
In the present study, the optimum conditions for the production of xylanase by immobilized spores of Trichoderma reesei SAF3 in calcium alginate beads were determined. The operational stability of the beads during xylanase production under semi-continuous
fermentation was also studied. The influence of alginate concentration (1, 2, 3, and 4%) and initial cell loading (100, 200,
300, 400, and 500 beads per flask) on xylanase production was considered. The production of xylanase was found to increase
significantly with increasing concentration of alginate and reached a maximum yield of 3.12 ± 0.18 U ml−1 at 2% (w/v). The immobilized cells produced xylanase consistently up to 10 cycles and reached a maximum level at the forth
cycle (3.36 ± 0.2 U ml−1). 相似文献
9.
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
10.
Luciana da Silva Rodrigues Maria Catarina Megumi Kasuya Arnaldo Chaer Borges 《Mycorrhiza》1999,8(5):263-266
We studied the viability of fragmented mycelium of Pisolithus
tinctorius and Paxillus
involutus entrapped in calcium alginate gel to determine the efficacy of this method of producing ectomycorrhizal fungus inoculum.
Fungi were grown in MMN solution at 28 °C before being fragmented in a blender and subsequently entrapped in calcium alginate.
We tested different ratios of alginate and mycelium suspension to 0.7 M CaCl2. The ratio 8 : 10 resulted in well-formed beads of the highest viability for Paxillus involutus (99%) and for Pisolithus tinctorius (75%). Paxillus
involutus mycelium was more than 90% viable when entrapped mycelium was 10 to 50 days old, and Pisolithus tinctorius attained its highest viability (55%) for 20- to 40-day-old mycelium. Gel entrapped Paxillus
involutus mycelium grew well at all temperatures after 30 days of storage, but viability significantly decreased after 60 days storage
at 6 °C on dry filter paper. For gel-entrapped Pisolithus tinctorius mycelium, viability was highest when stored at 25 °C in 0.7 M CaCl2. Entrapment of Paxillus
involutus fragmented mycelium in calcium alginate beads under the conditions that we propose can be used successfully to produce inoculum.
Accepted: 11 October 1998 相似文献
11.
The mycelia of Aspergillus niger, cultivated in a medium containing 45 g l−1 maltose, 66 g l−1 yeast extract, and 5 g l−1 K2HPO4 at 30°C and 200 rpm, were used as a biocatalyst in the glucosylation of ascorbic acid. Free mycelia from 3-day-old culture,
when used in a 6-h reaction with maltose as the acyl donor, gave 16.07 g l−1 ascorbic acid glucoside corresponding to a volumetric productivity of 2.68 g l−1 h−1 and a conversion of 67%. Mycelia from 3-day-old cultures were entrapped in calcium alginate beads and used as a catalyst
in the glucosylation of ascorbic acid. An ascorbic acid-to-maltose molar ratio of 1:9 was found to be optimum, and the conversion
reached 75% after 12 h. The concentration of ascorbic acid glucoside produced at this molar ratio was 17.95 g l−1, and the productivity was 1.5 g l−1 h−1. The biocatalyst was repeatedly used in a fixed bed bioreactor for the synthesis of ascorbic acid glucoside and approximately
17 g l−1 of ascorbic acid glucoside corresponding to a volumetric productivity of 1.42 g l−1 h−1 was produced in each use. The conversion was retained at 70% in each use. The entrapped mycelia also exhibited exceptionally
high reusability and storage stability. The product was purified to 85% by anion exchange and gel permeation chromatography
with a final yield of 75%. 相似文献
12.
Díaz-Barrera A Soto E Altamirano C 《Journal of industrial microbiology & biotechnology》2012,39(4):613-621
Alginates are polysaccharides that are used as thickening agents, stabilizers, and emulsifiers in various industries. These
biopolymers are produced by fermentation with a limited understanding of the processes occurring at the cellular level. The
objective of this study was to evaluate the effects of agitation rate and inlet sucrose concentrations (ISC) on alginate production
and the expression of the genes encoding for alginate-lyases (algL) and the catalytic subunit of the alginate polymerase complex (alg8) in chemostat cultures of Azotobacter vinelandii ATCC 9046. Increased alginate production (2.4 g l−1) and a higher specific alginate production rate (0.1 g g−1 h−1) were obtained at an ISC of 15 g l−1. Carbon recovery of about 100% was obtained at an ISC of 10 g l−1, whereas it was close to 50% at higher ISCs, suggesting that cells growing at lower sucrose feed rates utilize the carbon
source more efficiently. In each of the steady states evaluated, an increase in algL gene expression was not related to a decrease in alginate molecular weight, whereas an increase in the molecular weight of
alginate was linked to higher alg8 gene expression, demonstrating a relationship between the alg8 gene and alginate polymerization in A. vinelandii for the first time. The results obtained provide a possible explanation for changes observed in the molecular weight of alginate
synthesized and this knowledge can be used to build a recombinant strain able to overexpress alg8 in order to produce alginates with higher molecular weights. 相似文献
13.
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
14.
Objective: Transplantation of osteochondral allograft tissue can treat large joint defects but is limited by tissue availability, surgical
timing, and infectious disease transmission. Fresh allografts perform the best but requirements for infectious disease testing
delay the procedure with subsequent decrease in cell viability and function. Hypothermic storage at lower temperatures can
extend tissue banking time without loss of cell viability and, therefore, increase the supply of allograft tissue. This study
investigated the effects of different cryoprotectant solutions on intact AC at various subzero temperatures. Design: 10 mm porcine osteochondral dowels were immersed for 30 minutes in various combinations of solutions [(XVIVO, propylene glycol
(51% w/w), sucrose (46% w/w)] cooled to various subzero temperatures (−10, −15, and −20 °C), and held for 30 min. After warming,
70 μm slices were stained with membrane integrity dyes, viewed under fluorescence microscopy and cell recovery calculated
relative to fresh controls. Results: Results demonstrated excellent cell recovery (>75%) at −10°C provided ice did not form. Excellent cell recovery (>70%) occurred
at −15°C in solutions containing 51% propylene glycol but formation of extra-matrix ice in other solutions resulted in significant
cell loss. All groups had <6% cell recovery at −20°C and propylene glycol did not provide a protective effect even though
extra-matrix ice did not form Conclusions: These results suggest that extra-matrix ice plays an important role in cell damage during cryopreservation. Excellent cell
recovery can be obtained after storage at subzero temperatures if ice does not form. Hypothermic preservation at high subzero
temperatures may extend AC storage time in tissue banks compared to current techniques. 相似文献
15.
Champagne Claude P. Gardner Nancy Dugal France 《Journal of industrial microbiology & biotechnology》1994,13(6):367-371
Summary Immobilized cell technology was used to prepare concentrated cultures ofLactococcus lactis that lost only 22% of viability over a 30-day storage period at 4°C. Concentrated cultures ofL lactis CRA-1 were immobilized in calcium alginate beads and added to glycerol, NaCl or sucrose-NaCl solutions in order to obtain aw readings ranging from 0.91 to 0.97. The suspensions were subsequently placed at 4°C and viability (CFU g–1 of bead) was followed during storage. Viability losses were high at aw readings of 0.95 and 0.97 and pH dropped significantly (up to one unit) in the unbuffered solutions. Addition of 1% soytone or glycerophosphate helphed stabilize pH, and a beneficial effect on viability during storage was observed in the glycerol-soytone mix when the beads were added to the conservation solutions immediately following immobilization. When beads were added to the conservation solution immediately following immobilization, a 70% drop in cell counts occurred during the first 5 days of incubation. Dipping theL lactis-carrying beads in milk for 2h before mixing with the glycerolsoytone 0.93 aw solution reduced this initial 5-day viability loss. Cultures grown in the alginate beads also had good stability in the 0.93 aw glycerol-soytone solution, where 78% of the population was viable after 30 days at 4°C. The process could be used to store immobilized cells at a processing plant, or by suppliers of lactic starters who wish to ship cultures without freezing or drying. 相似文献
16.
Artificial seeds were obtained through encapsulation of protocorm-like bodies (PLBs) of Dendrobium densiflorum in calcium alginate beads. This paper demonstrates the alginate-encapsulation and conversion (complete plantlet regeneration) from PLBs, the effect of storage conditions (at different temperature; 4, 8, 16 °C, RT and duration; 15, 30, 45, 60, 75, 90 days) on viability of encapsulated plant materials as well as the assessment of genetic fidelity of the regenerants. Individual PLBs were encapsulated in calcium alginate beads for mass propagation, short-term storage and germplasm sharing. The superior gel matrix for encapsulation was obtained using 3 % sodium alginate and 100 mM calcium chloride (CaCl2·2H2O). The highest percentage of conversion (100 %) of encapsulated PLBs (capsules) was obtained on MS2 medium (MS medium + 2 mg/l BAP). Capsules were successfully stored till 60 days at 8 °C with conversion frequency of 95.5 %. Plantlets regenerated from encapsulated beads were acclimatized successfully with 95 % survival rate. A total of 40 primers were screened, out of which 10 primers successfully generated 39 scorable bands, ranging from 0.2 to 1.3 kb amplicons. The uniform RAPD banding profile among the plantlets derived from encapsulated PLBs following 60 days of storage confirmed genetic fidelity. 相似文献
17.
Jork A Thürmer F Cramer H Zimmermann G Gessner P Hämel K Hofmann G Kuttler B Hahn HJ Josimovic-Alasevic O Fritsch KG Zimmermann U 《Applied microbiology and biotechnology》2000,53(2):224-229
A simple procedure is described for the extraction and purification of alginate from the inner stipes of the kelp Laminaria pallida. Alginate yield was about 10–15% of the dry mass, with a 70:30 mannuronic/ guluronic acid ratio. Analysis of the purified
alginate revealed a low polyphenol content while proteins were below detection level. The purified alginate was highly viscous,
with 10–15 mPa s and 281 mPa s for a 0.1% and 0.5% solution, respectively, indicating a very high molecular mass (larger than
250 kDa). Bead formation occurred in the presence of divalent cations, but also in the presence of artificial serum (FCSIII)
without added divalent cations. The biocompatibility of the alginate was tested with the in vitro mice lymphocyte test as
well as by implantation of Ba2+ cross-linked beads beneath the kidney capsule of BB/OK rats. There was no evidence for significant mitogenic activity or
fibrotic reaction. Biocompatibility of the alginate was also demonstrated by the encapsulation of human chondrocytes into
Ca2+ cross-linked alginate beads. Immobilized chondrocytes grew and remained functional (i.e. they produced collagen).
Received: 14 June 1999 / Received revision: 6 September 1999 / Accepted: 10 September 1999 相似文献
18.
Mukunda Goswami Wazir S. Lakra T. Rajaswaminathan Gourav Rathore 《Molecular biology reports》2010,37(4):2043-2048
A new cell culture system (MRH) was developed for the first time from 2 months old freshwater prawn, Macrobrachium rosenbergii. Primary cultures were developed from heart tissues by explant culture technique. Cell outgrowth was obtained from the heart
explant after 14 days of explant culture. The culture medium used was Leibovitz-15 supplemented with 20% Fetal Bovine Serum
along with 1% prawn hemolymph serum, 0.1% glucose, 0.5% NaCl and antibiotics (Penicillin 10,000 Units ml−1, Streptomycin 10,000 μg ml−1, Amphotericin B 500 mg ml−1) with a final osmomolality of 470–550 mmol kg−1. The pH of the growth medium found suitable for the growth of the cells was 7.20. The viability of cells was found to be
60% when revived after a month of storage in liquid nitrogen. 相似文献
19.
Won-Kyu Yu Tae-Bin Yim Ki-Yong Lee Tae-Ryeon Heo 《Biotechnology and Bioprocess Engineering》2001,6(2):133-138
In this study, an attempt was made to increase the survival rate of bifidobacteria entrapped in alginate in the gastrointestinal
tract, and to investigate the potential industrial applications, for example lyophilized capsules and yogurt. First, the protective
effect of various food additives on bifidobacterial survivability was determined after exposure to simulated gastric juices
and bile salts. The additives used in this study were skim milk (SM), poly dextrose (PD), soy fiber (SF), yeast extract (YE),
chitosan (CS), κ-carageenan (κ-C) and whey, which were added at 0.6% concentration (w/v) to 3% alginate-bifidobacterial solution.
In the simulated gastric juices and bile salts, the protective effect of 0.6% skim milk-3% alginate (SM-A) beads on the survival
rate of bifidobacteria proved to be higher than the other additives. Second, the hydrogen ion permeation was detected through
SM-A vessel without bifidobacterial cells at different SM concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%). There were no
differences in terms of the pH decrease in SM-A vessels at 0.6%, 0.8%, and 1.0% (w/v) SM concentrations. The survival rate
of bifidobacteria in SM-A beads would appear to be related to the SM buffering capacity against hydrogen ions and its tendency
to reduce the pore size of bead. In this experiment, the survival rate of bifidobacteria entrapped in beads containing 0.6%
SM showed the highest viability after exposure to simulated gastric juices for 3 h, thereby indicating that 0.6% SM is the
optimum concentration for 3% alginate bead preparation. Third, the effect of SM-A beads on the freeze-drying and yogurt storage
for 10 days was investigated. SM-A beads were found to be more efficient for freeze drying and yogurt storage than untrapped
cells and the alginate bead. Consequently, the survival rate of bifidobacteria entrapped in SM-A beads was increased in simulated
gastric juices, bile salts and probiotic products such as lyophilized capsules and yogurt, SM-A beads can be expected to produce
high value probiotic products. 相似文献
20.
Protoplasts were isolated from cell suspensions derived from cotyledon and hypocotyl Gentiana kurroo (Royle). Cell walls were digested with an enzyme cocktail containing cellulase, macerozyme, driselase, hemicellulase and
pectolyase in CPW solution. Protoplast viability ranged from 88 to 96%. Three techniques of culture and six media were evaluated
in terms of their efficiency in producing viable cultures and regenerating whole plants. With liquid culture, cell division
occurred in only a low number of the protoplasts isolated, and no plant regeneration was successful. Cell division occurred
within 2 or 3 days in case of agarose solidified media. After 10 days of culture, the number of dividing cells was the highest
with modified MS medium in which NH4NO3 was replaced with 3.0 g l−1 glutamine. The best results were obtained with agarose bead cultures: plating efficiency was 68.7% and 58.1% for protoplasts
isolated from cotyledon and hypocotyl derived suspensions, respectively. The results were achieved with using medium containing
0.5 mg l−1 2,4-D + 1.0 mg l−1 kinetin or 2.0 mg l−1 BAP + 1.0 mg l−1 dicamba + 0.1 mg l−1 NAA + 80 mg l−1 adenine sulfate. Protocalluses transferred on the following composition of plant growth regulators: 0.5 mg l−1 2,4-D + 1.0 mg l−1 kinetin or 1.0 mg l−1 kinetin + 0.5 mg l−1 GA3 + 80.0 mg l−1 adenine sulfate developed in embryogenic cultures. However, the best embryo production occurred with the first one. Later
embryos were transferred to half-strength MS mineral salts to promote plants formation. Flow cytometry studies revealed increased
amounts of DNA in about one third of the regenerants. 相似文献