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1.
Summary Roquefortine synthesis with free and Ca-alginate immobilized Penicillium roqueforti cells was investigated under different culture conditions. Decreasing Ca-alginate concentration was related to increasing roquefortine production; free cells gave the best results. Formation of roquefortine was three times higher with mannitol and succinate than with sucrose as the carbon source; phosphate inhibited its biosynthesis in free cells by 23% to 32%. Relationships between cell density, 14C-tryptophan content of cells and roquefortine synthesis were shown. The special morphology of immobilized mycelia was demonstrated. 相似文献
2.
Michael Lohmeyer Wilfried Dierkes Hans-Jürgen Rehm 《Applied microbiology and biotechnology》1990,33(2):196-201
Summary The influence of inorganic phosphate and immobilization on cells of Claviceps purpurea strain 1029/N5 producing ergot peptides in shake culture was examined. Immobilization in Ca-alginate beads resulted in a marked reduction of some metabolic activities, i.e. the periods of alkaloid formation and cell growth were prolonged. High concentrations of inorganic phosphate (1 g/l KH2PO4) could reduce or stop alkaloid formation both by free and immobilized cells at any time during fermentation. The optimum phosphate concentration for alkaloid production by immobilized cells (about 0.5 mM) was a quarter of that required by free cells. This optimum shift was attributed to (i) the diminished phosphate demand of immobilized cells, due to their reduced metabolic activities, and (ii) the phosphate-dependent morphological behaviour of the biocatalyst. The observed decrease in alkaloid concentrations during later periods of the fermentation supported the idea of alkaloid-degradative enzymes, activated by high phosphate concentrations. Immobilization showed an advantageous influence on this undesirable effect.
Offprint requests to: H.J. Rehm 相似文献
3.
This research studied the effects of inorganic nutrient removal by free and immobilized Scenedesmus bijugatus cells, measured by algal growth (i.e., the chlorophyll a concentration) and the efficiency of the uptake of inorganic nutrients by the cells (uptake rate (b) and removal percentage) in water samples from the organically polluted Pinang River estuary (PRE). Water samples from the PRE were collected during low and high tide. S. bijugatus cells had a higher growth rate when incubated in low tide PRE water samples compared to high tide PRE water samples, with a growth rate of 0.29 µgml?1d?1 and 0.06 µgml?1d?1 for free and immobilized cells, respectively. S. bijugatus was able to more efficiently remove nitrogen, especially ammonium (81–94%), compared to phosphate (62–88%) from both low and high tide water samples. S. bijugatus cells in low tide PRE water samples recorded highest phosphate (0.36 mgL?1d?1 and 0.25 mgL?1d?1 for free and immobilized cells, respectively) and ammonium uptake rates (0.44 mgL?1d?1 and 0.29 mgL?1d?1 for free and immobilized cells respectively). Both inorganic nutrient removal and microalgal cell growth were not significantly different between free and immobilized S. bijugatus (p > 0.05). The data obtained indicated that the removal of nutrients by microalgae was affected by salinity and the immobilization technique applied may have good potential for bioremediation. 相似文献
4.
The effect of population size, redox potential, exogenous ATP and complexing agents on Cu uptake by free and immobilized cyanobacteriumNostoc calcicola
Bréb. has been studied. Cu uptake was regulated by the population size. In such comparisons, the immobilized cells had a greater
longevity. Low pH conditions enhanced Cu uptake. Exogenous ATP (10 μmol/L) supplied to dark-grown free and immobilized cells
did not support Cu uptake to the extent of light-grown cells. Experiments involving natural as well as synthetic complexing
agents clearly established the superiority of soil extract and spent medium over EDTA (10 μmol/L), in sequestering Cu in free
as well as immobilized cells. 相似文献
5.
In order to better understand the high plasmid stability in immobilized recombinant E. coli cells, the effects of dilution rate on the pTG201 plasmid stability, the copy number, and the catechol 2,3-dioxygenase (encoded by XyIE gene) production were, at first, studied in free E. coli W3101 continuous cultures in minimal media. It was found that decreasing specific growth rate increased the plasmid copy number and the catechol 2,3-dioxygenase activity but the stability decreased. In continuous culture with immobilized cells, an increase was shown in plasmid copy number and catechol 2,3-dioxygenase activity probably due to the distribution of growth in the gel beads. Besides mechanical properties of gel beads which may allow limited cell divisions, the increase in plasmid copy number is involved in enhanced plasmid stability in immobilized cells. In the same way, an experiment conducted in LB medium dealing with competition between pTG201-free and pTG201-containing E. coli B cells was described. It was shown that the competition was not more pronounced in gel bead compared to a free system. The effects of nutritional limitations on pTG201 plasmid stability and catechol 2,3-dioxygenase activity during chemostat cultivations in free and immobilized E. coli B cells were also investigated. It was found that immobilization of cells increased the stability of pTG201 even under glucose, nitrogen, or phosphate limited cultures. However in the case of magnesium depleted culture, pTG201 was shown to be relatively instable and a decrease in viable cell number during the immobilized continuous culture was observed. By contrast to the free system, the catechol 2,3-dioxygenase activity increased in immobilized cells under all culture conditions used. 相似文献
6.
Ana M. Anselmo Joaquim M. S. Cabral Júlio M. Novais 《Applied microbiology and biotechnology》1989,31(2):200-203
Summary Spores of Fusarium flocciferum were inserted in porous celite beads. The effects of bead size, adsorption time course, washing cycle and spore concentration on spore loading were investigated. Cell loadings up to 50% (dry weight/beads) were obtained. The degradation of phenol using adsorbed cells was studied in batch experiments. The immobilized cell system was shown to efficiently degrade high concentrations of the substrate (up to 2.0 g/l) and to remain active for more than 2 motths. The oxygen uptake rate of free and immobilized cells was determined at various concentrations of phenol. The kinetic constants K
s=85 mg/l, K
i=345 mg/l and SMI=170 mg/l were estimated from the experimental data by linearization of the Haldane function for the free cells. The uptake rates exhibited by the confined cells were lower (30%) than those obtained for free cells and no significant differences were found for phenol concentrations between 150 and 1200 mg/l. 相似文献
7.
The effect of chitosan immobilization of Scenedesmus spp. cells on its viability, growth and nitrate and phosphate uptake was investigated. Scenedesmus sp. (strains 1 and 2) and Scenedesmus obliquus immobilized in chitosan beads showed high viability after the immobilization process. Immobilized Scenedesmus sp. strain 1 had a higher growth rate than its free living counterpart. Nitrate and phosphate uptake by immobilized cells of Scenedesmus sp. (strain 1), freely suspended cells and blank chitosan beads (without cells) were evaluated. Immobilized cells accomplished a 70% nitrate and 94% phosphate removal within 12h of incubation while free-living cells removed 20% nitrate and 30% phosphate within 36 h of treatment. Blank chitosan beads were responsible for up to 20% nitrate and 60% phosphate uptake at the end of the experiment. Chitosan is a suitable matrix for immobilization of microalgae, particularly Scenedesmus sp., but this system should be improved before its application for water quality control. 相似文献
8.
This study investigated the growth rate of chitosan-immobilized cells of the marine cyanobacterium Synechococcus elongatus and its potential application in the removal of nitrogen and phosphorus for wastewater treatment. Immobilized cell cultures
had a lag phase of growth due to the immobilization method, and their growth rate was similar to that of free-living cell
cultures. Ammonia removal was higher in free cells (54%) than in immobilized cells (29%), but nitrate removal was similar
in immobilized (38%) and free cells (44%); phosphorus removal was more efficient in free cells (88%) than in immobilized cells
(77%). Chlorophyll a and protein content were higher in immobilized cells. Our study demonstrates that S. elongatus immobilized into chitosan capsules can remove nutrients and is able to maintain a growth rate comparable to that of free
cells in culture. 相似文献
9.
Octavio Perez‐Garcia Luz E. De‐Bashan Juan‐Pablo Hernandez Yoav Bashan 《Journal of phycology》2010,46(4):800-812
Heterotrophic growth of microalgae presents significant economic advantages over the more common autotrophic cultivation. The efficiency of growth and nitrogen, phosphorus, and glucose uptake from synthetic wastewater was compared under heterotrophic, autotrophic, and mixotrophic regimes of Chlorella vulgaris Beij. immobilized in alginate beads, either alone or with the bacterium Azospirillum brasilense. Heterotrophic cultivation of C. vulgaris growing alone was superior to autotrophic cultivation. The added bacteria enhanced growth only under autotrophic and mixotrophic cultivations. Uptake of ammonium by the culture, yield of cells per ammonium unit, and total volumetric productivity of the culture were the highest under heterotrophic conditions when the microalga grew without the bacterium. Uptake of phosphate was higher under autotrophic conditions and similar under the other two regimes. Positive influence of the addition of A. brasilense was found only when light was supplied (autotrophic and mixotrophic), where affinity to phosphate and yield per phosphate unit were the highest under heterotrophic conditions. The pH of the culture was significantly reduced in all regimes where glucose was consumed, similarly in heterotrophic and mixotrophic cultures. It was concluded that the heterotrophic regime, using glucose, is superior to autotrophic and mixotrophic regimes for the uptake of ammonium and phosphate. Addition of A. brasilense positively affects the nutrient uptake only in the two regimes supplied with light. 相似文献
10.
Summary
Dactylium dendroides cells were immobilized with calcium alginate, calcium pectate and k-carrageenan. Alginate immobilized cells produced relatively
small amounts of (D-galactose: O2 oxidoreductase, EC 1.1.3.9, GOase). Pectate immobilized cells gave the best yield of GOase, which was comparable with that
obtained with free cells, and productivity could be extended up to 28 days (7 cycles). Controlled dosage of phosphate to the
medium markedly improved GOase production with higher yields per cycle than with free cells. 相似文献
11.
A mathematical model of the biodegradation of xenobiotics by microbial cells attached to particles of granulated activated
carbon was developed. The model allowed the quantitative evaluation of different characteristics of the biofilm behavior:
retarded microbial growth, increased concentration of immobilized cells compared to suspended cultures, potential cell detachment
from the solid support and consequent independent growth of free cells. The applicability of the model was demonstrated for
our own experimental data for 1,2- dichloroethane (DCA) biodegradation by Klebsiella oxytoca VA 8391 cells attached to granulated activated carbon. Two types of reactors, recirculated batch and continuous flow bioreactor,
were studied. It was shown that in all investigated cases, the major contribution to DCA biodegradation was provided by the
immobilized cells. Furthermore, immobilized cells were found to tolerate much higher substrate concentration and dilution
rates in continuous culture than the free cells. 相似文献
12.
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
13.
We studied the enhanced production of high quality biomass, δ-aminolevulinic acid (δ-ALA), bilipigments, and antioxidants
from five tropical blue green algae (cyanobacteria) in a full factorial design using free and immobilized cells in batch culture.
Production of nutraceuticals was high in spray dried powder prepared from immobilized cell cultures. Nostochopsis lobatus showed superiority over rest of the species with respect to bilipigments, δ-ALA, nutritive value, antioxidant capacity, and
ascorbate oxidase (APX) activity. Antioxidative capacity of phycobiliproteins extracted from these cyanobacteria (121.15 μM
TE/g, Nostoc verrucosum to 217.62 μM TE/g, Nostochopsis lobatus) was invariably higher than those observed for higher plant sources and substantially increased under immobilized cell culture
condition. Antioxidative enzyme, ascorbate oxidase remained stable in dry food preparations with considerably high activity
under immobilized cell preparations (APXmax, 3.40 μmol/min/mg chlorophyll). These observations have important connotations in light of upcoming food and nutraceutical
industries in the global market. Use of immobilized cells in batch culture could be an effective approach for scaling up production
for commercial use. 相似文献
14.
A. S. Abdel-Razek T. M. Abdel-Ghany S. A. Mahmoud H. H. El-Sheikh M. S. Mahmoud 《World journal of microbiology & biotechnology》2009,25(12):2137-2145
This paper discusses the possible application to use free and immobilized Cunninghamella elegans for the removal of cobalt from aqueous waste solutions. Results indicated that the maximum uptake occurred at; pH 4.0–5.5 ± 0.2,
temperature range between 15 and 50°C and stirring rate 250 rpm. The uptake increased with the increase of metal ion concentration
up to 40 ppm. Also, it was found that the best biomass weights used for biosorption were 0.25 and 0.5 g for both free and
immobilized biomass. The reuse of control alginate beads, alive and dead immobilized Cunninghamella elegans beads was investigated for five cycles. Results showed that the percent uptake decreased slightly after the first cycle.
While, in the case of alginate beads there was increase in the second cycle then returned to the same level of uptake. The
uptake of cobalt in the presence of Cr(VI) and Cd(II) at different mixture concentrations 40, 50 and 60 ppm was investigated.
The results showed that the uptake amount of Co(II) in the presence of other metal ions was lower than Co(II) alone except
for Ca-alginate beads. SEM studies for control alginate beads, alive and dead immobilized Cunninghamella elegans beads were conducted to investigate the beads before and after the accumulation of cobalt ions. 相似文献
15.
Motoki Fujimura Jyoji Kato Tetsuya Tosa Ichiro Chibata 《Applied microbiology and biotechnology》1984,19(2):79-84
Summary The immobilized growing cell system using Serratia marcescens was applied to continuous L-arginine production. From the determination of oxygen uptake rate, it was shown that the cells entrapped in carrageenan gel were in an oxygen-limited state due to the diffusion barrier to oxygen transport created by the gel layer. This limited state in gel was relieved by supply of oxygen-enriched gas instead of air into the medium. The maximum population of immobilized cells increased to five times that of free cells with the supply of pure oxygen gas. The L-arginine-producing activity of the immobilized growing cells was proportional to the concentration of oxygen gas supplied and was 6 mg/h per millilitre in gel supplied with pure oxyges gas. The continuous L-arginine containing production was constantly maintained by controlling the medium penicillin G at pH 6.5 and more than 10 mg/ml of L-arginine were obtained at 10h of residence time for at least 12 days. 相似文献
16.
A unicellular green microalga, Chlorella sorokiniana, was immobilized on loofa (Luffa cylindrica) sponge and successfully used as a new biosorption system for the removal of lead(II) ions from aqueous solutions. The biosorption of lead(II) ions on both free and immobilized biomass of C. sorokiniana was investigated using aqueous solutions in the concentration range of 10–300 mg/L. The biosorption of lead(II) ions by C. sorokiniana biomass increased as the initial concentration of lead(II) ions increased in the medium. The maximum biosorption capacity for free and immobilized biomass of C. sorokiniana was found to be 108.04 and 123.67 mg lead(II)/g biomass, respectively. The biosorption kinetics were found to be fast, with 96 % of adsorption within the first 5 min and equilibrium reached at 15 min. The adsorption of lead(II) both by free and immobilized C. sorokiniana biomass followed the Langmuir isotherm. The biosorption capacities were detected to be dependent on the pH of the solution; and the maximum adsorption was obtained at a solution pH of about 5. The effect of light metal ions on lead(II) uptake was also studied and it was shown that the presence of light metal ions did not significantly affect lead(II) uptake. The loofa sponge‐immobilized C. sorokiniana biomass could be regenerated using 0.1 M HCl, with up to 99 % recovery. The desorbed biomass was used in five biosorption‐desorption cycles, and no noticeable loss in the biosorption capacity was observed. In addition, fixed bed breakthrough curves for lead(II) removal were presented. These studies demonstrated that loofa sponge‐immobilized biomass of C. sorokiniana could be used as an efficient biosorbent for the treatment of lead(II) containing wastewater. 相似文献
17.
A bacterial consortium able to mineralize two herbicides, glyphosate (Pseudomonas 4ASW) and diuron (Arthrobacter sp. N4 and Delftia acidovorans), was cultivated in both a synthetic culture medium without phosphate and a sediment extract medium. In the aim at optimizing
glyphosate and diuron mineralization, all the combinations, i.e., free and/or immobilized cells in Ca-alginate beads were
tested. With the synthetic medium, the simultaneous mineralization of glyphosate and diuron required at least the immobilization
of Pseudomonas 4ASW. Conversely, with the sediment extract medium, only the mineralization of diuron was observed, most probably, because
of both nutrient deficiency and phosphate in the sediment extract medium. 相似文献
18.
Copper uptake by free and immobilized cyanobacterium 总被引:1,自引:0,他引:1
Abstract Copper uptake in free and immobilized cells of the cyanobacterium Nostoc calcicola has been examined. The immobilized cells invariably maintained a higher profile of Cu intake rate (12.7 nmol mg−1 protein min−1 ) over the free cells (6.0 nmol mg−1 protein min−1 ). The total Cu uptake in immobilized cells was almost two and a half-times more than their free cell counterpart under identical experimental conditions. Also, the immobilized cells showed a stronger positive correlation between Cu adsorption and uptake. The results have been discussed in terms of improved metabolic efficiency of immobilized cells. 相似文献
19.
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
20.
Neelakanteshwar K. Patil T. B. Karegoudar 《World journal of microbiology & biotechnology》2005,21(8-9):1493-1498
Summary Di-n-butylphthalate (DBP) is one of the phthalate esters (PAEs) used in the manufacture of plasticizers, insect repellents and
synthetic fibres and contributes to environmental pollution. We report a novel bacterium belonging to the genus, Bacillus (NCIM 5220), which has the ability to utilize DBP as the sole source of carbon and energy. This bacterium was immobilized
in alginate. The degradation of DBP by immobilized cells was compared with free cells. The effects on the degradation of DBP
of different factors like gel (alginate) concentration, gel bead size, temperature, and pH were investigated. Oxygen uptake
in the presence of DBP by free and immobilized cells was also studied. The results showed that the degradation of DBP by immobilized
cells was more efficient than by free cells. Further, the effect of various factors tested on the degradation of DBP by alginate-immobilized
cells showed that the degradation of DBP was remarkably affected by alginate concentration between 2 and 5% and drastically
decreased between bead size 2 and 5 mm. A change of 10 °C of reaction temperature from 30 to 40 °C did not alter the degradation
of DBP, and maximum degradation was appeared to be favoured over a broad pH range of 6.5–7.5 for immobilized cells as compared
to free cells, which showed an optimum temperature of about 35 °C and pH of 7.0. The immobilized cells showed higher oxidation
of DBP than free cells. Thus more efficient degradation of DBP could be achieved by immobilizing Bacillus sp. in alginate beads. 相似文献