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1.
A spiral packed-bed bioreactor inoculated with microorganisms obtained from activated sludge was used to conduct a feasibility
study for phenol removal. The reactor was operated continuously at various phenol loadings ranging from 53 to 201.4 g m−3 h−1, and at different hydraulic retention times (HRT) in the range of 20–180 min to estimate the performance of the device. The
results indicated that phenol removal efficiency ranging from 82.9 to 100% can be reached when the reactor is operated at
an HRT of 1 h and a phenol loading of less than 111.9 g m−3 h−1. At an influent phenol concentration of 201.4 g m−3, the removal efficiency increased from 18.6 to 76.9% with an increase in the HRT (20–120 min). For treatment of phenol in
the reactor, the maximum biodegradation rate (V
m) was 1.82 mg l−1 min−1; the half-saturation constant (K
s), 34.95 mg l−1. 相似文献
2.
Granular activated carbon (GAC) was incorporated into hollow fiber membrane bioreactors for the biodegradation of 1,000 mg
phenol l−1 through immobilization of Pseudomonas
putida. The phenol was removed within 25 h in the hybrid bioreactor, comparing with 31 h for a GAC-free bioreactor. Sorption, biodegradation,
desorption, and bioregeneration were four steps for the phenol removal during batch operation. 相似文献
3.
Covalent immobilization of Aspergillus awamori NRRL 3112 was conducted onto modified polyacrylonitrile membrane with glutaraldehyde as a coupling agent. The polymer carrier
was preliminarily modified in an aqueous solution of NaOH and 1,2-diaminoethane. The content of amino groups was determined
to be 0.58 mgeq g−1. Two ways of immobilization were used—in the presence of 0.2 g l−1 phenol and without phenol. The capability of two immobilized system to degrade phenol (concentration—0.5 g l−1) as a sole carbon and energy source was investigated in batch experiments. Seven cycles of phenol biodegradation were conducted.
Better results were obtained with the immobilized system prepared in the presence of phenol, regarding degradation time and
phenol biodegradation rate. Scanning electron micrographs of the polyacrylonitrile membrane/immobilized Aspergillus awamori NRRL at the beginning of repeated batch cultivation and after the 7th cycle were compared. After the 7th cycle of cultivation
the observations showed large groups of cells. The results from the batch experiments with immobilized system were compared
to the results produced by the free strain. Phenol biodegradation experiments were carried out also in a bioreactor with spirally
wound membrane with bound Aspergillus awamori NRRL 3112 in a regime of recirculation. 10 cycles of 0.5 g l−1 phenol biodegradation were run consecutively to determine the degradation time and rate for each cycle. The design of the
bioreactor appeared to be quite effective, providing large membrane surface to bind the strain. 相似文献
4.
Phenol is one of the major toxic pollutants in the wastes generated by a number of industries and needs to be eliminated before
their discharge. Although microbial degradation is a preferred method of waste treatment for phenol removal, the general inability
of the degrading strains to tolerate higher substrate concentrations has been a bottleneck. Immobilization of the microorganism
in suitable matrices has been shown to circumvent this problem to some extent. In this study, cells of Pseudomonas sp. CP4, a laboratory isolate that degrades phenol, cresols, and other aromatics, were immobilized by entrapment in Ca-alginate
and agar gel beads, separately and their performance in a fluidized bed bioreactor was compared. In batch runs, with an aeration
rate of 1 vol−1 vol−1 min−1, at 30°C and pH 7.0 ± 0.2, agar-encapsulated cells degraded up to 3000 mg l−1 of phenol as compared to 1500 mg l−1 by Ca-alginate-entrapped cells whereas free cells could tolerate only 1000 mg l−1. In a continuous process with Ca-alginate entrapped cells a degradation rate of 200 mg phenol l−1 h−1 was obtained while agar-entrapped cells were far superior and could withstand and degrade up to 4000 mg phenol l−1 in the feed with a maximum degradation rate of 400 mg phenol l−1 h−1. The results indicate a clear possibility of development of an efficient treatment technology for phenol containing waste
waters with the agar-entrapped bacterial strain, Pseudomonas sp. CP4. 相似文献
5.
Combining chemical and biological treatments is a potentially economic approach to remove high concentration of recalcitrant
compounds from wastewaters. In the present study, the biodegradation of 1,4-benzoquinone, an intermediate compound formed
during phenol oxidation by chlorine dioxide, was investigated using Pseudomonas putida (ATCC 17484) in batch and continuous bioreactors. Batch experiments were conducted to determine the effects of 1,4-benzoquinone
concentration and temperature on the microbial activity and biodegradation kinetics. Using the generated data, the maximum
specific growth rate and biodegradation rate were determined as 0.94 h−1 and 6.71 mg of 1,4-benzoquinone l−1 h−1. Biodegradation in a continuous bioreactor indicated a linear relationship between substrate loading and biodegradation rates
prior to wash out of the cells, with a maximum biodegradation rate of 246 mg l−1 h−1 observed at a loading rate of 275 mg l−1 h−1 (residence time: 1.82 h). Biokinetic parameters were also determined using the steady state substrate and biomass concentrations
at various dilution rates and compared to those obtained in batch cultures. 相似文献
6.
SA Ahmad NA Shamaan NM Arif GB Koon MY Shukor MA Syed 《World journal of microbiology & biotechnology》2012,28(1):347-352
A locally isolated Acinetobacter sp. Strain AQ5NOL 1 was encapsulated in gellan gum and its ability to degrade phenol was compared with the free cells. Optimal
phenol degradation was achieved at gellan gum concentration of 0.75% (w/v), bead size of 3 mm diameter (estimated surface
area of 28.26 mm2) and bead number of 300 per 100 ml medium. At phenol concentration of 100 mg l−1, both free and immobilized bacteria exhibited similar rates of phenol degradation but at higher phenol concentrations, the
immobilized bacteria exhibited a higher rate of degradation of phenol. The immobilized cells completely degrade phenol within
108, 216 and 240 h at 1,100, 1,500 and 1,900 mg l−1 phenol, respectively, whereas free cells took 240 h to completely degrade phenol at 1,100 mg l−1. However, the free cells were unable to completely degrade phenol at higher concentrations. Overall, the rates of phenol
degradation by both immobilized and free bacteria decreased gradually as the phenol concentration was increased. The immobilized
cells showed no loss in phenol degrading activity after being used repeatedly for 45 cycles of 18 h cycle. However, phenol
degrading activity of the immobilized bacteria experienced 10 and 38% losses after the 46 and 47th cycles, respectively. The
study has shown an increased efficiency of phenol degradation when the cells are encapsulated in gellan gum. 相似文献
7.
Toxic at low concentrations, phenol is one of the most common organic pollutants in air and water. In this work, phenol biodegradation
was studied in extreme conditions (80°C, pH = 3.2) in a 2.7 l bioreactor with the thermoacidophilic archaeon Sulfolobus solfataricus 98/2. The strain was first acclimatized to phenol on a mixture of glucose (2000 mg l−1) and phenol (94 mg l−1) at a constant dissolved oxygen concentration of 1.5 mg l−1. After a short lag-phase, only glucose was consumed. Phenol degradation then began while glucose was still present in the
reactor. When glucose was exhausted, phenol was used for respiration and then for biomass build-up. After several batch runs
(phenol < 365 mg l−1), specific growth rate (μX) was 0.034 ± 0.001 h−1, specific phenol degradation rate (qP) was 57.5 ± 2 mg g−1 h−1, biomass yield (YX/P) was 52.2 ± 1.1 g mol−1, and oxygen yield factor
( \textY\textX/\textO 2 ) \left( {{\text{Y}}_{{{\text{X}}/{\text{O}}_{ 2} }} } \right) was 9.2 ± 0.2 g mol−1. A carbon recovery close to 100% suggested that phenol was exclusively transformed into biomass (35%) and CO2 (65%). Molar phenol oxidation constant
( \textY\textO 2 /\textP ) \left( {{\text{Y}}_{{{\text{O}}_{ 2} /{\text{P}}}} } \right) was calculated from stoichiometry of phenol oxidation and introducing experimental biomass and CO2 conversion yields on phenol, leading to values varying between 4.78 and 5.22 mol mol−1. Respiratory quotient was about 0.84 mol mol−1, very close to theoretical value (0.87 mol mol−1). Carbon dioxide production, oxygen demand and redox potential, monitored on-line, were good indicators of growth, substrate
consumption and exhaustion, and can therefore be usefully employed for industrial phenol bioremediation in extreme environments. 相似文献
8.
Isoflavonoid production in cell cultures of Pueraria tuberosa as influenced by an angiospermic parasite, Cuscuta reflexa, was studied. During the time course, maximum isoflavonoid content was recorded when Cuscuta elicitor was added on day 15 of culture. Among various concentrations of elicitor tried, 1 g l−1 of Cuscuta elicitor was found to be the most effective. The optimized elicitation conditions were used in vessels of varying capacity
where maximum yield of ~91 mg l−1 of isoflavonoid was recorded in a 2-l bioreactor which was about 19% higher than the control cultures. In this case, puerarin
content increased up to 11 mg l−1 which was 580% higher that the value recorded in the control cultures. In the bioreactor, 8 days of elicitation was optimal
for the high accumulation of isoflavonoid, giving productivity of ~4 mg l−1 day−1. The study showed persistent high isoflavonoid yield even during scale-up. Use of a preparation of Cuscuta reflexa as an elicitor is reported for the first time. The increase in isoflavonoid content was elicitor dose-dependent and can be
explored to trigger high yields of isoflavonoid/secondary metabolites in production. 相似文献
9.
Xiangyuan Deng Song Qin Qun Zhang Peng Jiang Yulin Cui Xiaokun Li 《Plant Cell, Tissue and Organ Culture》2009,97(3):253-261
A human acidic fibroblast growth factor gene, hafgf, was successfully transferred into Laminaria japonica (kelp) gametophytes via microprojectile bombardment using the biolistic PDS-1000/He gene gun. Following phosphinothricin
screening, PCR detection and Southern blot analysis, transgenic L. japonica gametophytes were cultivated in an illuminated bubble-column bioreactor to optimize growth conditions. A maximal final dry
cell density of 1,695 mg l−1 was obtained in a batch culture having an initial dry cell density of 129.75 mg l−1. This was achieved using an aeration rate of 1.08 l air min−1 l−1 culture in a medium containing 1.5 mM inorganic nitrate and 0.15 mM phosphate. In addition, the relationship between different
nitrogen sources and growth of transgenic gametophytes indicated that both urea and sodium nitrate were effective nitrogen
sources for cell growth, while ammonium ions inhibited growth of these gametophytes. 相似文献
10.
Single-culture aerobic granules with <Emphasis Type="Italic">Acinetobacter calcoaceticus</Emphasis> 总被引:1,自引:0,他引:1
Aerobic granules are cultivated by a single bacterial strain, Acinetobacter calcoaceticus, in a sequencing batch reactor (SBR). This strain presents as a good phenol reducer and an efficient auto coagulator in the
presence of phenol, mediated by heat-sensitive adhesins proteins. Stable 2.3-mm granules were formed in the SBR following
a 7-week cultivation. These granules exhibit excellent settling attributes and degrade phenol efficiently at concentrations
of 250–2,000 mg l−1. The corresponding phenol degradation rate reached 993.6 mg phenol g−1 volatile suspended solids (VSS) day−1 at 250 mg l−1 phenol and 519.3 mg phenol g−1 VSS day−1 at 2,000 mg l−1 phenol concentration. Meanwhile, free A. calcoaceticus cells were fully inhibited at phenol >1,500 mg l−1. Denaturing gradient gel electrophoresis fingerprint profile demonstrated no genetic modification in the strain during aerobic
granulation. The present single-strain granules showed long-term structural stability and performed high phenol degrading
capacity and high phenol tolerance. The confocal laser scanning microscopic test revealed that live A. calcoaceticus cells principally distributed at 200–250 μm beneath the outer surface, with an extracellular polymeric substance layer covering
them to defend phenol toxicity. Autoaggregation assay tests demonstrated the possibly significant role of secreted proteins
on the formation of single-culture A. calcoaceticus granules. 相似文献
11.
Jing Wang Hua Yang Hong Lu Jiti Zhou Jing Wang Chunli Zheng 《World journal of microbiology & biotechnology》2009,25(5):875-881
An aerobic microbial consortium constructed by the combination of Rhodotorula mucilaginosa Z1, Streptomyces albidoflavus Z2 and Micrococcus luteus Z3 was immobilized in polyurethane foam and its ability to degrade nitrobenzene was investigated. Batch experimental results
showed that polyurethane-foam-immobilized cells (PFIC) more efficiently degrade 200–400 mg l−1 nitrobenzene than freely suspended cells (FSC). Kinetics of nitrobenzene degradation by PFIC was well described by the Andrews
equation. Compared with FSC, PFIC exhibited better reusability (over 100 times) and tolerated higher shock-loadings of nitrobenzene
(1,000 mg l−1). Moreover, In the presence of salinity (≤5% NaCl, w/v), phenol (≤150 mg l−1) and aniline (≤50 mg l−1), respectively, degradation efficiency of nitrobenzene by PFIC reached over 95%. Even in the presence of both 100 mg l−1 phenol and 50 mg l−1 aniline, over 75% nitrobenzene was removed by PFIC in 36 h. Therefore, the immobilization of the defined consortium in polyurethane
foam has application potential for removing nitrobenzene in industrial wastewater treatment system. 相似文献
12.
Start-up and inhibition analysis of the Anammox process seeded with anaerobic granular sludge 总被引:4,自引:0,他引:4
Chong-jian Tang Ping Zheng Qaisar Mahmood Jian-wei Chen 《Journal of industrial microbiology & biotechnology》2009,36(8):1093-1100
The longer start-up period of the Anammox process is due to the very low cellular yield and growth rates of Anammox bacteria.
Nitrite inhibition is considered to be the key factor in the instability of the Anammox process during the operation. However,
little attention was paid to the inhibitory effect of pH and free ammonia. This paper presents start-up and inhibition analysis
of an Anammox biofilm reactor seeded with anaerobic granular sludge. Results showed that the start-up period could be divided
into the sludge lysis phase, lag phase, propagation phase, stationary phase and inhibition phase. Optimization control could
be implemented correspondingly to accelerate the start-up of Anammox bioreactors. Effluent pH increased to 8.7–9.1 when the
nitrogen removal rate was higher than 1,200 mg l−1 day−1. The free ammonia concentration was accompanied with a higher level of 64–73 mg l−1. Inhibitory effects of high pH and free ammonia on Anammox bacteria contributed to the destabilization of the Anammox bioreactor
during the first 125 days with influent KHCO3 of 0.5 g l−1. Increasing the suffering capacity in the inlet by dosing 1.25 g KHCO3 l−1 effectively reduced the pH variation, and the nitrogen removal performance of the reactor was further developed. 相似文献
13.
Ethrel treatment enhanced isoflavonoids accumulation in cell suspension cultures of Pueraria tuberosa, a woody legume 总被引:1,自引:0,他引:1
The cell cultures of Pueraria tuberosa, a perennial leguminous lianas, were maintained in modified MS medium (KNO3 475 mg l−1, thiamine 1 mg l−1, biotin 1 mg l−1, calcium pantothenate 1 mg l−1) containing 0.1 mg l−1 2,4,5-trichloroacetic acid and 0.1 mg l−1 kinetin. Isoflavonoids (puerarin, genistin, daidzein, genistein) accumulation in cell suspension cultures was increased by
14-fold to ~12 mg l−1 after 48 h of adding 100 μM ethrel. Ethrel inhibitors (silver nitrate and silver thiosulfate) completely inhibited this effect
in the presence of ethrel and isoflavonoids were not detected in the spent medium. The increase was dose dependent and can
be explored to trigger high yield of isoflavonoids production. 相似文献
14.
Results of this study describe the feasibility of anaerobic treatment of highly concentrated phenol synthetic wastewater using
an anaerobic fluidized bed reactor (AFBR) in both continuous and batch modes. Wastewater with a maximum load of 2,100 mg C·l−1 was prepared using phenol (maximum concentration of 1,600 mg C·l−1) as substrate and a mixture of acetic, propionic and butyric acids (500 mg C·l−1) as co-substrate. AFBR reached total organic carbon (TOC) and phenol removal efficiency over 95% treating the highest organic
loading rate (OLR) containing phenol studied for this kind of reactor (5.03 g C·l−1·d−1). The phenol loading rate rise caused volumetric biogas rate increase up to 4.4 l·l−1·d−1 (average yield of 0.28 l CH4·g−1 CODremoved) as well as variation in the biogas composition; the CO2 percentage increased while the CH4 percentage decreased. Morphological examination of the bioparticles at 4.10 g C·l−1·d−1, revealed significant differences in the biofilm structure, microbial colonization and bacterial morphological type development.
The five batch assays showed that phenol degradation may be favoured by the presence of volatile fatty acids (VFAs) (co-metabolism),
whereas VFAs degradation may be inhibited by phenol. AFBR reached initial phenol degradation velocity of 0.25 mg C·l−1·min−1. 相似文献
15.
Cell cultures of Cayratia trifolia (Vitaceae), a tropical lianas, were maintained in Murashige and Skoog’s medium containing 0.25 mg l−1 NAA, 0.2 mg l−1 kinetin and casein hydrolysate 250 mg l−1. Cell suspension cultures of C. trifolia accumulate stilbenes (piceid, resveratrol, viniferin, ampelopsin), which on elicitation by any of 500 μM salicylic acid,
100 μM methyl jasmonate, 500 μM ethrel and 500 mg l−1 yeast extract, added on the 7th day, were enhanced by 3- to 6-fold (5–11 mg l−1) by the 15th day. 相似文献
16.
Yantree Devi Sankar-Thomas Katja Saare-Surminski Reinhard Lieberei 《Plant Cell, Tissue and Organ Culture》2008,95(2):163-173
The present study describes a protocol for plant regeneration via somatic embryogenesis in temporary immersion system (TIS)
for Camptotheca acuminata. Somatic embryos were induced by culturing hypocotyl segments from 14-day-old in vitro grown C. acuminata seedlings in TIS. Hypocotyl segments were placed in culture vessels modified with a mechanical device to support the fixation
of explants. Cultures were maintained under a 16 h photoperiod with a light intensity of 60 μmol m−2 s−1 PPF at 25 ± 1°C. After 16 weeks of incubation embryogenic calli were formed above the edge of the mechanical device in the
basal Murashige and Skoog (MS) medium containing 35 g l−1 sucrose and without hormonal supplementation. For plantlet regeneration, somatic embryos at cotyledonary stage were cultured
in three different concentrations of 6-benzylamino-purine (0.5, 1.0 and 1.5 mg l−1 BAP) and in plant growth regulator (PGR) free medium. In general, 0.5 mg l−1 BAP was found to be the most effective concentration for growth and development of Camptotheca embryos in TIS. Conversion of somatic embryos into plantlets was also successfully achieved on sterile substrates moistened
with 0.5 mg l−1 BAP. Plantlets derived from cotyledonary embryos were rooted in vitro with 0.5 mg l−1 indole-3-butyric acid (IBA) before transfer to ex vitro conditions. 相似文献
17.
François Coutte Didier Lecouturier Saliha Ait Yahia Valérie Leclère Max Béchet Philippe Jacques Pascal Dhulster 《Applied microbiology and biotechnology》2010,87(2):499-507
Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air–liquid contactor to prevent foam formation. Three different configurations
were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a
submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen
uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory
bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume
was in the same range: 242, 230, and 188 mg l−1 for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l−1 for BB1, 207 mg l−1 for BB2, and 393 mg l−1 for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer
coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with
the submerged polypropylene membrane. 相似文献
18.
Michael Pescheck Marco Antonio Mirata Bianca Brauer Ulrich Krings Ralf Günter Berger Jens Schrader 《Journal of industrial microbiology & biotechnology》2009,36(6):827-836
A closed gas loop bioprocess was developed to improve fungal biotransformation of monoterpenes. By circulating monoterpene-saturated
process gas, the evaporative loss of the volatile precursor from the medium during the biotransformation was avoided. Penicillium solitum, isolated from kiwi, turned out to be highly tolerant towards monoterpenes and to convert α-pinene to a range of products
including verbenone, a valuable aroma compound. The gas loop was mandatory to reproduce the production of 35 mg L−1 verbenone obtained in shake flasks and also in the bioreactor. Penicillium digitatum DSM 62840 regioselectively converted (+)-limonene to the aroma compound α-terpineol, but shake flask cultures revealed a
pronounced growth inhibition when initial concentrations exceeded 1.9 mM. In the bioreactor, toxic effects on P. digitatum during biotransformation were alleviated by starting a sequential feeding of non-toxic limonene portions after a preceding
growth phase. Closing the precursor-saturated gas loop during the biotransformation allowed for an additional replenishment
of limonene via the gas phase. The gas loop system led to a maximum α-terpineol concentration of 1,009 mg L−1 and an average productivity of 8–9 mg L−1 h−1 which represents a doubling of the respective values previously reported. Furthermore, a molar conversion yield of up to
63% was achieved.
M. Pescheck and M. A. Mirata have contributed equally to this work. 相似文献
19.
Maizirwan Mel Abdul Rafiz Abdul Rahman Mohamad Ramlan Mohamed Salleh Yumi Zuhanis Has-Yun Hashim 《World journal of microbiology & biotechnology》2008,24(9):1923-1927
The study was done to improve the viability of the RC1 hybridoma cell in order to produce more amount of monoclonal antibody
(mAb). By using the optimized media, the cell had been cultured in two bioreactor systems which were the MiniPerm and Stirred
Tank bioreactor (ST bioreactor), and the results were compared to the one obtained by using the T-Flask bioreactor which was
used as a standard. The results showed that the ST bioreactor was able to improve the viability of the cell to the value of
91.8% which was a little bit better than the one obtained by the MiniPerm bioreactor (88.6%) and far better than that of achieved
by the T-Flask bioreactor (76.4%). This was well correlated with the good growth performance of the cell in the ST bioreactor
with the specific growth rate (μ) value of 0.0289 h−1 followed by MiniPerm bioreactor with the value of 0.0243 h−1 and then the T-Flask with the value of 0.0151 h−1. The low value of doubling time (t
d
) obtained in the ST bioreactor (24 h) compared to the one obtained in the MiniPerm (29 h) and T-Flask bioreactor (46 h) had
also contributed to the higher value of cell viability. As a result a higher concentration of mAb was able to be produced
by the ST bioreactor (0.42 g l−1) compared to that of the MiniPerm (0.37 g l−1) and T-Flask bioreactor (0.23 g l−1). 相似文献
20.
Phenol biodegradation in a continuous system of immobilized Candida tropicalis NCIM 3556 was studied. The bioreactor was simple, it had a feed inlet from the bottom and the effluent outlet from top, no
supplementary oxygen was supplied, the reactor was operated continuously for 116 days. Initially the column was run continuously
with a feed concentration of 2 g l−1 for 42 days whence a degradation of >97% was achieved. The feed concentration was then increased to 3 g l−1, for which a ~80% biodegradation was sustained for 90 days after which there was a steady decrease in the performance. When
the phenol degradation was reduced to ~50% in 116 days, the reactor was stopped. The efficiency of free cells recycled every
24 h and immobilized cells were compared; it was estimated that repeated reuse of free cells in batch mode gave an overall
efficiency of 0.102 g phenol degradation g−1 cell wet weight in 12 days. In contrast, the immobilized system of the same biomass had a longer working lifetime of ~4 months
indicating an efficiency of 3.72 g phenol g−1 cell wet wt. 相似文献