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1.
The transformation of fluorobenzene (FB) by whole cell expressing toluene-4-monooxygenase (T4MO) resulted in the formation
of various hydroxylated products. The predominant product was either 4-fluorophenol (4FP) or 4-fluorocatechol (4Fcat) depending
on the ratio of biocatalyst to substrate concentration. The transformation of 1 mM FB by whole cells (1.5 mg CDW/ml) gave
a 52% yield of 4Fcat as a single product. The yield of 4Fcat was improved 1.6-fold (80%) by adding 10 mM ascorbic acid to
the biotransformations. A combination of two biocatalysts (whole cells expressing T4MO and cell free mushroom tyrosinase)
also resulted in the transformation of FB (5 mM) to higher concentrations of 4Fcat (1.8 mM) compared to a whole cell biotransformation
alone. However, mixed products were formed and the yield of 4Fcat from FB was lower using the two-step (tandem) method (27%)
compared to the use of whole cells of P. mendocina KR1 alone (80%). 相似文献
2.
Biotransformation of halophenols using crude cell extracts of<Emphasis Type="Italic"> Pseudomonas putida</Emphasis> F6 总被引:1,自引:0,他引:1
Brooks SJ Doyle EM Hewage C Malthouse JP Duetz W O' Connor KE 《Applied microbiology and biotechnology》2004,64(4):486-492
Crude cell extracts of Pseudomonas putida F6 transformed 4-substituted fluoro-, chloro-, bromo- and iodo-phenol without the exogenous addition of cofactors. The rate of substrate consumption decreased with increasing substituent size (F>Cl>Br>I). Biotransformations resulted in greater than 95% utilisation of the halogenated substrate. Product accumulation was observed in incubations with 4-chloro, 4-bromo- and 4-iodo-phenol. These products were identified as the corresponding 4-substituted catechols. Transformation of 4-fluorophenol did not result in the accumulation of the corresponding catechol; however, manipulation of the reaction conditions by incorporation of ascorbic acid culminated in the formation of 4-fluorocatechol. Cell extracts of P. putida F6 also showed activity towards a 3-substituted phenol, namely 3-fluorophenol, resulting in the formation of a single product, 4-fluorocatechol. 相似文献
3.
Alberto Domínguez Francisco J. Deive Lorenzo Pastrana Maria L. Rúa Maria A. Longo M. Angeles Sanroman 《Bioprocess and biosystems engineering》2010,33(3):347-354
Several studies in laboratory-scale bioreactors are undertaken in order to verify the beneficial effect of thermal spring
water in the culture medium of Thermus thermophilus HB27. Two bioreactor configurations, stirred tank and airlift, are investigated to determine the most suitable one to develop
a continuous process. Water mineral composition affects the lipolytic enzyme secretion and growth of T. thermophilus HB27 in both bioreactor configurations. Furthermore, the lipolytic activity is strongly enhanced when stirred tank bioreactor
is used. Moreover, operation in a stirred tank at an agitation rate of 650 rpm leads to the highest total lipolytic activity
(intra- and extracellular enzyme) around 280 U/L after 32 h. Continuous cultures operating in the optimised conditions determined
in batch cultures are carried out. It is noticeable that the stirred tank bioreactor was able to operate in a continuous flow
mode without operational problems. In addition, the lipolytic activity obtained is about 2-fold higher than that attained
in batch cultures. 相似文献
4.
High cell density cultivation of recombinant yeasts and bacteria under non-pressurized and pressurized conditions in stirred tank bioreactors 总被引:1,自引:0,他引:1
Knoll A Bartsch S Husemann B Engel P Schroer K Ribeiro B Stöckmann C Seletzky J Büchs J 《Journal of biotechnology》2007,132(2):167-179
This study demonstrates the applicability of pressurized stirred tank bioreactors for oxygen transfer enhancement in aerobic cultivation processes. The specific power input and the reactor pressure was employed as process variable. As model organism Escherichia coli, Arxula adeninivorans, Saccharomyces cerevisiae and Corynebacterium glutamicum were cultivated to high cell densities. By applying specific power inputs of approx. 48kWm(-3) the oxygen transfer rate of a E. coli culture in the non-pressurized stirred tank bioreactor was lifted up to values of 0.51moll(-1)h(-1). When a reactor pressure up to 10bar was applied, the oxygen transfer rate of a pressurized stirred tank bioreactor was lifted up to values of 0.89moll(-1)h(-1). The non-pressurized stirred tank bioreactor was able to support non-oxygen limited growth of cell densities of more than 40gl(-1) cell dry weight (CDW) of E. coli, whereas the pressurized stirred tank bioreactor was able to support non-oxygen limited growth of cell densities up to 225gl(-1) CDW of A. adeninivorans, 89gl(-1) CDW of S. cerevisiae, 226gl(-1) CDW of C. glutamicum and 110gl(-1) CDW of E. coli. Compared to literature data, some of these cell densities are the highest values ever achieved in high cell density cultivation of microorganisms in stirred tank bioreactors. By comparing the specific power inputs as well as the k(L)a values of both systems, it is demonstrated that only the pressure is a scaleable tool for oxygen transfer enhancement in industrial stirred tank bioreactors. Furthermore, it was shown that increased carbon dioxide partial pressures did not remarkably inhibit the growth of the investigated model organisms. 相似文献
5.
The thermophilic Bacillus sp. A2 transformed various halophenols. 2-Chlorophenol, 2-bromophenol, 3-bromophenol and 2-fluorophenol were transformed under resting cell conditions at 60°C to 3-chlorocatechol, 3-bromocatechol, 4-bromocatechol and 3-fluorocatechol, respectively. The hydroxylation of 3-bromophenol occurred at the proximal and distal position relative to the halogen substituent. In complex medium this strain completely transformed 2-chlorophenol and 2-bromophenol at concentrations up to 1 mM. Concomitantly, an accumulation of oxygen-and temperature sensitive halocatechols was observed. 3-Chlorocatechol possesses a half-life of 11.5 h at 60°C and is therefore readily decomposed during incubation. The hydroxylating system was present in phenolgrown cells but not in glucose-grown cells. The hydroxylase activity could also be induced by 2-chlorophenol. The product, 3-chlorocatechol, is not a substrate for the catechol 2,3-dioxygenase.Abbreviations 2-CP
2-chlorophenol
- DCP
dichlorophenol
- TCP
trichlorophenol
- tetraCP
tetrachlorophenol
- MIC
minimal inhibitory concentration
- CF
chloride-free
- CFG
chloride-free plus glucose
- CFGY
chloride-free plus glycerol
- CFP
chloride-free plus phenol
- CAM
chloramphenicol 相似文献
6.
Eun-Ju Kim Jong-Rok Jeon Young-Mo Kim Kumarasamy Murugesan Yoon-Seok Chang 《Applied microbiology and biotechnology》2010,87(4):1569-1577
The aerobic metabolism of monofluorophenols (mono-FPs) by the actinomycete, Pseudonocardia benzenivorans, was studied. This strain was able to grow on 4-fluorophenol (4-FP) and readily transform 2- and 3-fluorophenol to the corresponding
metabolites. The detailed mechanism of mono-FPs degradation by P. benzenivorans was elucidated from enzymatic assays and the identification of reaction intermediates by high-performance liquid chromatography
(HPLC) and gas chromatography–mass spectrometry. Two types of fluorocatechols (i.e., 3- and 4-fluorocatechol) were identified
as the key transformation products. During 4-FP degradation, only 4-fluorocatechol was detected, and a stoichiometric level
of fluoride was released. Both fluorocatechols were observed together in cultures containing 3-fluorophenol (3-FP), while
only 3-fluorocatechol was found to accumulate in 2-fluorophenol (2-FP)-containing cultures. Whole-cell extracts of P. benzenivorans expressed catechol 1,2-dioxygenase activity, indicating that the transformation of the three tested mono-FPs proceeded via
ortho-cleavage pathway. The results presented in this paper provide comprehensive information regarding the metabolism of mono-FPs
by a single bacterium. 相似文献
7.
Michelin M Polizeli Mde L Silva DP Ruzene DS Vicente AA Jorge JA Terenzi HF Teixeira JA 《Journal of industrial microbiology & biotechnology》2011,38(12):1979-1984
Fungi producing high xylanase levels have attracted considerable attention because of their potential industrial applications.
Batch cultivations of Aspergillus terricola fungus were evaluated in stirred tank and airlift bioreactors, by using wheat bran particles suspended in the cultivation
medium as substrate for xylanase and β-xylosidase production. In the stirred tank bioreactor, in physical conditions of 30°C,
300 rpm, and aeration of 1 vvm (1 l min−1), with direct inoculation of fungal spores, 7,475 U l−1 xylanase was obtained after 36 h of operation, remaining constant after 24 h. In the absence of air injection in the stirred
tank reactor, limited xylanase production was observed (final concentration 740 U l−1). When the fermentation process was realized in the airlift bioreactor, xylanase production was higher than that observed
in the stirred tank bioreactor, being 9,265 U l−1 at 0.07 vvm (0.4 l min−1) and 12,845 U l−1 at 0.17 vvm (1 l min−1) aeration rate. 相似文献
8.
《Process Biochemistry》2007,42(1):93-97
Successful scale-up of Azadirachta indica suspension culture for azadirachtin production was done in stirred tank bioreactor with two different impellers. The kinetics of biomass accumulation, nutrient consumption and azadirachtin production of A. indica cell suspension culture were studied in a stirred tank bioreactor equipped with centrifugal impeller and compared with similar bioreactor with a setric impeller to investigate the role of O2 transfer efficiency of centrifugal impeller bioreactor on overall culture metabolism. The maximum cell mass for centrifugal impeller bioreactor and stirred tank bioreactor (with setric impeller) were 18.7 and 15.5 g/L (by dry cell weight) and corresponding azadirachtin concentrations were 0.071 and 0.05 g/L, respectively. Glucose and phosphate were identified as the major growth-limiting nutrients during the bioreactor cultivation. The centrifugal impeller bioreactor demonstrated less shearing and improved O2 transfer than the stirred tank bioreactor equipped with setric impeller with respect to biomass and azadirachtin production. 相似文献
9.
Trejo-Tapia G Cerda-García-Rojas CM Rodríguez-Monroy M Ramos-Valdivia AC 《Biotechnology progress》2005,21(3):786-792
Cell growth, monoterpenoid oxindole alkaloid (MOA) production, and morphological properties of Uncaria tomentosa cell suspension cultures in a 2-L stirred tank bioreactor were investigated. U. tomentosa (cell line green Uth-3) was able to grow in a stirred tank at an impeller tip speed of 95 cm/s (agitation speed of 400 rpm), showing a maximum biomass yield of 11.9 +/- 0.6 g DW/L and a specific growth rate of 0.102 d(-1). U. tomentosa cells growing in a stirred tank achieved maximum volumetric and specific MOA concentration (467.7 +/- 40.0 microg/L, 44.6 +/- 5.2 microg/g DW) at 16 days of culture. MOA chemical profile of cell suspension cultures growing in a stirred tank resembled that of the plant. Depending on culture time, from the total MOA produced, 37-100% was found in the medium in the bioreactor culture. MOA concentration achieved in a stirred tank was up to 10-fold higher than that obtained in Erlenmeyer flasks (agitated at 110 rpm). In a stirred tank, average area of the single cells of U. tomentosa increased up to 4-fold, and elliptical form factor increased from 1.40 to 2.55, indicating enlargement of U. tomentosa single cells. This work presents the first report of U. tomentosa green cell suspension cultures that grow and produce MOA in a stirred tank bioreactor. 相似文献
10.
The possibility of using in situ addition of anion-exchange resin for the removal of acetate in the culture aimed at improving growth of E. coli and expression of periplasmic human interferon-α2b (PrIFN-α2b) was studied in shake flask culture and stirred tank bioreactor. Different types of anion-exchange resin were evaluated and the concentration of anion-exchange resin was optimized using response surface methodology. The addition of anion-exchange resins reduced acetate accumulation in the culture, which in turn, improved growth of E. coli and enhanced PrIFN-α2b expression. The presence of anion-exchange resins did not influence the physiology of the cells. The weak base anion-exchange resins, which have higher affinity towards acetate, yielded higher PrIFN-α2b expression as compared to strong anion-exchange resins. High concentrations of anion-exchange resin showed inhibitory effect towards growth of E. coli as well as the expression of PrIFN-α2b. The maximum yield of PrIFN-α2b in shake flask culture (501.8 μg/L) and stirred tank bioreactor (578.8 μg/L) was obtained at ion exchange resin (WA 30) concentration of 12.2 g/L. The production of PrIFN-α2b in stirred tank bioreactor with the addition of ion exchange resin was about 1.8-fold higher than that obtained in fermentation without ion exchange resin (318.4 μg/L). 相似文献
11.
Summary The degradation rate of hydrocarbons in oily sludge obtained from a flotation unit by free and immobilized cells in shaking flasks and in a stirred tank reactor was investigated. For the biodegration of 3.3% hydrocarbons free cells and cells immobilized on granular clay were used. Free cells needed 7–8 weeks to use 30% of the 3.3% hydrocarbons, whereas with immobilized cells the same result was obtained after 3–4 weeks only. In shaken flasks with high hydrocarbon concentrations (8%), immobilized Candida parapsilosis degraded 90% of the hydrocarbons in the oily sludge within 3 weeks, while free cells degraded only 27.5% in the same period. In degradation experiments with a bioreactor, free and immobilized cells of the isolate ISO-OS BÜ 20 showed better results compared to cultures in shaken flasks due to better aeration and mixing. Free cells degraded 50% of the 5% hydrocarbon-containing oily sludge in 7 weeks, whereas immobilized cells gave the same result after only 4 weeks.Offprint requests to: H.-J. Rehm 相似文献
12.
Ducros E Ferrari M Pellegrino M Raspanti C Bogni C 《Bioprocess and biosystems engineering》2009,32(1):143-148
The modified rotating simplex method has been successfully used to determine the best combination of agitation rate and aeration
rate for maximum production of extracellular proteases by Staphylococcus aureus mutant RC128, in a stirred tank bioreactor operated in a discontinuous way. This mutant has shown altered exoprotein production,
specially enhanced protease production. Maximum production of proteases (15.28 UP/ml), measured using azocasein as a substrate,
was obtained at exponential growth phase when the bioreactor was operated at 300 rpm and at 2 vvm with a volumetric oxygen
transfer coefficient (K
L
a) of 175.75 h−1. These conditions were found to be more suitable for protease production. 相似文献
13.
Moonen MJ Rietjens IM van Berkel WJ 《Journal of industrial microbiology & biotechnology》2001,26(1-2):35-42
The biological Baeyer–Villiger oxidation of acetophenones was studied by 19F nuclear magnetic resonance (NMR). The 19F NMR method was used to characterise the time-dependent conversion of various fluorinated acetophenones in either whole cells
of Pseudomonas fluorescens ACB or in incubations with purified 4′-hydroxyacetophenone monooxygenase (HAPMO). Whole cells of P. fluorescens ACB converted 4′-fluoroacetophenone to 4-fluorophenol and 4′-fluoro-2′-hydroxyacetophenone to 4-fluorocatechol without the
accumulation of 4′-fluorophenyl acetates. In contrast to 4-fluorophenol, 4-fluorocatechol was further degraded as evidenced
by the formation of stoichiometric amounts of fluoride anion. Purified HAPMO catalysed the strictly NADPH-dependent conversion
of fluorinated acetophenones to fluorophenyl acetates. Incubations with HAPMO at pH 6 and 8 showed that the enzymatic Baeyer–Villiger
oxidation occurred faster at pH 8 but that the phenyl acetates produced were better stabilised at pH 6. Quantum mechanical
characteristics explained why 4′-fluoro-2′-hydroxyphenyl acetate was more sensitive to base-catalysed hydrolysis than 4′-fluorophenyl
acetate. All together, 19F NMR proved to be a valid method to evaluate the biological conversion of ring-substituted acetophenones to the corresponding
phenyl acetates, which can serve as valuable synthons for further production of industrially relevant chemicals. Journal of Industrial Microbiology & Biotechnology (2001) 26, 35–42.
Received 20 April 2000/ Accepted in revised form 16 September 2000 相似文献
14.
Nawakorn Chotisubha-anandha Sitanan Thitiprasert Vasana Tolieng Nuttha Thongchul 《Bioprocess and biosystems engineering》2011,34(2):163-172
Rhizopus oryzae was immobilized on a cotton matrix in a static bed bioreactor. Compared with free cells in a stirred tank bioreactor, immobilized
R. oryzae in this bioreactor gave higher lactic acid production but lower ethanol production. The highest lactic acid production rate
(2.09 g/L h) with the final concentration of 37.83 g/L from 70 g/L glucose was achieved when operating the bioreactor at 700 rpm
and 0.5 vvm air. To better understand the relationship between shear effects (agitation and aeration) and R. oryzae morphology and metabolism, oxygen transfer rate, fermentation kinetics, and lactate dehydrogenase activity were determined.
In immobilized cell culture, higher oxygen transfer rate and lactic acid production were achieved but lower lactate dehydrogenase
activity was found as compared with those in free cell culture operated at the same conditions. These results clearly imply
that mass transport was the rate controlling step in lactic acid fermentation by R. oryzae. 相似文献
15.
Sang-Yoon Lee Won Hur Gyu Heon Cho Dong-Il Kim 《Biotechnology and Bioprocess Engineering》2001,6(1):72-74
TransgenicNicotiana tabacum cells were cultivated for the production of murine granulocyte macrophage-colony stimulating factor (mGM-CSF) in both a stirred,
tank biore|actor and an airlift bioreactor with draft tube. Cell growth and mGM-CSF production in the airlift bioreactor were
found to be better than those achieved in the stirred tank bioreactor. In the airlift bioreactor. 9.0 g/L of cells and 2.2
ng/mL of mGM-CSF were obtained (11.0 g/L and 2.4 ng/mL, respectively in shake flasks). Although the lag period was prolonged
and mGM-CSF production was lowered by 33% in the stirred tank bioreactor as compared to the control culture, the maximum cell
density was increased up to 12.0 g/L due to better mixing by agitation at the higher cell density. 相似文献
16.
A Gram-positive bacterial strain capable of aerobic biodegradation of 4-fluorophenol (4-FP) as the sole source of carbon and
energy was isolated by selective enrichment from soil samples collected near an industrial site. The organism, designated
strain IF1, was identified as a member of the genus Arthrobacter on the basis of 16S ribosomal RNA gene sequence analysis. Arthrobacter strain IF1 was able to mineralize 4-FP up to concentrations of 5 mM in batch culture. Stoichiometric release of fluoride
ions was observed, suggesting that there is no formation of halogenated dead-end products during 4-FP metabolism. The degradative
pathway of 4-FP was investigated using enzyme assays and identification of intermediates by gas chromatography (GC), GC–mass
spectrometry (MS), high-performance liquid chromatography, and liquid chromatography–MS. Cell-free extracts of 4-FP-grown
cells contained no activity for catechol 1,2-dioxygenase or catechol 2,3-dioxygenase, which indicates that the pathway does
not proceed through a catechol intermediate. Cells grown on 4-FP oxidized 4-FP, hydroquinone, and hydroxyquinol but not 4-fluorocatechol.
During 4-FP metabolism, hydroquinone accumulated as a product. Hydroquinone could be converted to hydroxyquinol, which was
further transformed into maleylacetic acid and β-ketoadipic acid. These results indicate that the biodegradation of 4-FP starts
with a 4-FP monooxygenase reaction that yields benzoquinone, which is reduced to hydroquinone and further metabolized via
the β-ketoadipic acid pathway. 相似文献
17.
Joo Shun Tan Tau Chuan Ling Shuhaimi Mustafa Yew Joon Tam Ramakrishnan Nagasundara Ramanan Arbakariya B. Ariff 《Process Biochemistry》2013,48(4):551-558
A stirred tank bioreactor (STB) integrated with an expanded bed adsorption (EBA) system containing anion-exchange resin (Diaion WA30) was developed for in situ removal of acetate to increase the production of α-interferon-2b (α-PrIFN-2b) by Escherichia coli (E. coli). Although the total acetate (9.79 g/L) secreted by E. coli in the integrated STB/EBA system was higher than that in a bioreactor with dispersed resin or a conventional batch bioreactor, cell growth (14.97 g/L) and α-PrIFN-2b production (867.4 μg/L) were significantly improved owing to the high efficiency of acetate removal from the culture. The production of α-PrIFN-2b in the integrated STB/EBA system was improved by 3-fold and 1.4-fold over that obtained in a conventional batch bioreactor and a bioreactor containing dispersed resins, respectively. 相似文献
18.
Hollow-fiber membrane bioreactors were developed with granular activated carbon (GAC) for the biodegradation of phenol using
Pseudomonas putida. Hollow fibers showed similar structure with/without GAC incorporated; while GAC hollow fiber had a stronger phenol adsorption
capacity. In batch biotransformation experiments, complete depletion of 1000 mg phenol l−1 (at which concentration free cells cannot grow) was accomplished in the reactor within 18 h in the hybrid bioreactor, comparing
with 23 h in the GAC free bioreactor. Desorption and bioregeneration of the hollow-fiber membrane were believed to be the
key for the enhancement of bioreactor performance. At continuous running, the GAC bioreactor showed its superiority over the
GAC free bioreactor during start-up and elevated loading phase. More than 90% of the phenol was transformed in the GAC bioreactor
when the phenol loading was <24 mg h−1. The better bioreactor performance may be due to the enhanced mass transportation and adsorption capacity with the incorporation
of GAC. 相似文献
19.
A comparison of orbitally‐shaken and stirred‐tank bioreactors: pH modulation and bioreactor type affect CHO cell growth and protein glycosylation
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Dominique T. Monteil Valentin Juvet Jonathan Paz Marc Moniatte Lucia Baldi David L. Hacker Florian M. Wurm 《Biotechnology progress》2016,32(5):1174-1180
Orbitally shaken bioreactors (OSRs) support the suspension cultivation of animal cells at volumetric scales up to 200 L and are a potential alternative to stirred‐tank bioreactors (STRs) due to their rapid and homogeneous mixing and high oxygen transfer rate. In this study, a Chinese hamster ovary cell line producing a recombinant antibody was cultivated in a 5 L OSR and a 3 L STR, both operated with or without pH control. Effects of bioreactor type and pH control on cell growth and metabolism and on recombinant protein production and glycosylation were determined. In pH‐controlled bioreactors, the glucose consumption and lactate production rates were higher relative to cultures grown in bioreactors without pH control. The cell density and viability were higher in the OSRs than in the STRs, either with or without pH control. Volumetric recombinant antibody yields were not affected by the process conditions, and a glycan analysis of the antibody by mass spectrometry did not reveal major process‐dependent differences in the galactosylation index. The results demonstrated that OSRs are suitable for recombinant protein production from suspension‐adapted animal cells. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1174–1180, 2016 相似文献
20.
Pedro Nuno de Sousa Sampaio Hélia Neto Pedro Poejo Susana Maria T. Serrazina Maria Salomé Soares Pais 《Plant Cell, Tissue and Organ Culture》2010,101(3):311-321
Cynara cardunculus suspension cells were transformed by particle bombardment to overexpress the cypro11 gene coding for cyprosin B. Green fluorescent protein, used as a visual reporter through mgfp4-ER gene, facilitates the screening of transformed cells at the initial stages when antibiotics cause generalized cell death.
mgfp4-ER lacks a cryptic intron and has an endoplasmic reticulum target sequence, these traits conferring an adequate use as screenable
marker for transformed cells. Selected transformed cells, grown in a bioreactor, produced 3.8 g dcw l−1 of biomass, 80 mg l−1 of total protein and 2,060 U ml−1 of enzymatic activity. Specific activity of cyprosin B, purified by anionic-exchange chromatography, was 215 U mg−1 with a purification degree of 8.3-fold. The cyprosin B activity is optimal at 42°C for pH 5.1 and is inhibited by pepstatin
A. The results encourage the overexpression of cypro11 gene in transformed C. cardunculus cells leading to high yields of cyprosin B production in bioreactor, which can be considered adequate for industrial production. 相似文献