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1.
Effect of carbon starvation on the rate of dihexylsulfosuccinate (DHSS) biotransformation byComamonas terrigena was determined. The protein content during the starvation was stable in all variants and did not change during the transformation
cycle. All starved cultures exhibited a higher biotransformation rate than a non-starved control. Cells ofC. terrigena exposed for 16 h in media with no C source showed the highest specific biotransformation rate (144% of the non-starved culture).
Extension of the starvation to 2 d led to a decrease of the rate to close to that found in non-starved cells. 相似文献
2.
Starvation for carbon and energy sources accelerated the biotransformation of the anion-active surfactant dihexyl sulfosuccinate
(DHS) byComamonas terrigena cells. Cloramphenicol (Cm) added at different time intervals to non-starved cells inhibited the DHS transformation. The largest
difference between cells treated and non-treated by Cm was observed for a 16-h-starvation period. Protein synthesisde novo during starvation enhanced the DHS biotransformation efficiency. A partial transformation of DHS in the presence of Cm indicated
the constitutive character of enzymes involved in primary DHS biodegradation. 相似文献
3.
Takatoshi Kimura Chihiro Ishikawa Antonio Osorio-Lozada Karen T. Robins Makoto Hibi 《Bioscience, biotechnology, and biochemistry》2013,77(10):1772-1776
Rhodococcus rubropertinctus N82 possesses unique regiospecific hydroxylation activity in biotransformation of compounds. In this study, the ability of whole cells of the strain R. rubropertinctus N82 in biotransformation was studied. The hydroxylation activity resulted in transforming 6,7-dihydro-4H-thieno[3,2-c]-pyridine-5-carboxylic acid tert-butyl ester (LS1) into 2-hydroxy-6,7-dihydro-4H-thieno[3,2-c]-pyridine-5-carboxylic acid tert-butyl ester (LP1), a pharmaceutical intermediate. By optimizing conditions for the hydroxylating biotransformation using whole cells of R. rubropertinctus N82 as biocatalyst, 3.3?mM LP1 was successfully produced from 4?mM LS1 with a molar yield of 83%. Thus, effective method was newly developed to produce LP1, which is a synthetic intermediate of a platelet inhibitor active pharmaceutical ingredient drug, prasugrel. 相似文献
4.
The biotransformation of racemic 1-phenylethanol (30 mg) with plant cultured cells of basil (Ocimum basilicum cv. Purpurascens, 5 g wet wt) by shaking 120 rpm at 25°C for 7 days in the dark gave (R)-(+)-1-phenylethanol and acetophenone in 34 and 24% yields, respectively. The biotransformation can be applied to other 1-arylethanols
and basil cells oxidized the (S)-alcohols to the corresponding ketones remaining the (R)-alcohols in excellent ee. 相似文献
5.
Shanmugam B Luckman S Summers M Bernan V Greenstein M 《Journal of industrial microbiology & biotechnology》2003,30(5):308-314
The possibility of using solid supports and intermittent substrate feeding to manipulate biotransformation by fungi was examined,
with amoxapine as a model compound. Cunninghamella elegans ATCC 8688a grown as free cells in six-well plates showed 7-hydroxyamoxapine as the major metabolite of amoxapine biotransformation.
However, when cells were grown in the presence of activated carbon, N-formyl-7-hydroxyamoxapine was formed as the major metabolite. Intermittent feeding of amoxapine also favored the formation
of N-formyl-7-hydroxyamoxapine. 相似文献
6.
Gluconobacter oxydans is widely used in several biotechnological applications, where sorbitol or mannitol is commonly used as carbon source at
high concentration. In this study, a membrane-bound glucose dehydrogenase-deficient strain (GDHK) was constructed to eliminate
growth problems on glucose caused by direct oxidation of glucose in the medium. To achieve improved growth properties for
the GDHK strain on glucose, a laboratory adaptive evolution experiment was performed with glucose as the sole carbon source.
Results indicated evident, albeit modest, improvements in cell growth after a 50-day (about 430 generations) experimental
evolution on glucose. The maximum specific growth rate and biomass yield of the resulting GDHE50 strain were increased around
1.35- to 1.4-fold compared with those of the GDHK strain. Meanwhile, two types of biotransformation reactions using resting
cells of G. oxydans were investigated. Significant elevations in biotransformation performance of the GHDE50 strain were observed in comparison
with that of the wild-type strain. In addition, resting cells of the GDHE50 strain grown on a relatively low concentration
of glucose (10 g/l) could catalyze the biotransformation of glycerol to dihydroxyacetone and ethylene glycol to glycolic acid
as efficient as the wild-type G. oxydans cultured on higher concentration of sorbitol or other carbon sources. These results suggest very favorable prospects of using
glucose to lower production cost in many important industrial biocatalysis and biotransformation processes. 相似文献
7.
L-Phenylacetylcarbinol (L-PAC), an important drug intermediate, can be produced by biotransformation of benzaldehyde, mainly
by yeast cultures but also by Zymomonas mobilis. The biotransformation by free cells, immobilized cells, mutant organisms, purified pyruvate decarboxylase as well as the
use of bioreactors, the downstream processing of L-PAC and the industrial applications have been reviewed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Calcium is a known signalling molecule in eukaryotic cells and plays a central role in the regulation of many cellular processes.
In the following study, we report on the effect of external calcium treatments on the biotransformation of ginsenoside Rb1
to ginsenoside Rd by Paecilomyces bainier 229-7. We observed that the intracellular calcium content of P. bainier 229-7 mycelia was increased in response to exposure to high external Ca2+ concentrations. Both ginsenoside Rd biotransformation and β-glucosidase activity were both found to be dependent on the external
calcium concentration. At an optimal Ca2+ concentration of 45 mM, maximal ginsenoside Rd bioconversion rate of 92.44% was observed and maximal β-glucosidase activity
of 0.1778 U was reached in a 72-h biotransformation. The Ca2+ channel blocker Verapamil blocked the trans-membrane influx of calcium and decreased ginsenoside Rd biotransformatiom. In
addition, β-glucosidase activity and ginsenoside Rd content decreased by 36.0 and 29.2% respectively after a 72-h incubation
in the presence of 0.05 mM Calmodulin (CaM) antagonist Perphenazine. These results suggest that both Ca2+ channels and CaM are involved in ginsenoside Rd biotransformation via regulation of β-glucosidase activity. This is the first
report regarding the effects of calcium signal transduction on biotransformation and enzyme activity in fungi. 相似文献
9.
The biotransformation of decanones with immobilized cells of Nicotiana tabacum led to the formation of their corresponding alcohols of high optical purity. 相似文献
10.
ABSTRACTThe biotransformation of citral, an industrially important monoterpenoid, has been extensively studied using many microbial biocatalysts. However, the metabolic pathways involved in its biotransformation are still unclear, because citral is a mixture of the trans-isomer geranial and the cis-isomer neral. Here, we applied the heterologous expression of geoA, a gene encoding geraniol dehydrogenase that specifically converts geraniol to geranial and nerol to neral, to identify the metabolic pathways involved in the biotransformation of citral. Acinetobacter sp. Tol 5 was employed in order to demonstrate the utility of this methodology. Tol 5 transformed citral to (1R,3R,4R)-1-methyl-4-(1-methylethenyl)-1,3-cyclohexanediol and geranic acid. Biotransformation of citral precursors (geraniol and nerol) by Tol 5 transformant cells expressing geoA revealed that these compounds were transformed specifically from geranial. Our methodology is expected to facilitate a better understanding of the metabolic pathways involved in the biotransformation of substrates that are unstable and include geometric isomers. 相似文献
11.
André L. Patrício Silva Poliane K. Batista Augusto D. Filho Claudionor S. do Nascimento Junior Julio S. Rebouças 《Biocatalysis and Biotransformation》2017,35(3):185-190
?-Caprolactone (?-CL) was obtained with excellent conversion and short reaction times from the substrates cyclohexenone, cyclohexanone and cyclohexanol using whole cells of Brazilian Geotrichum candidum (CCT 1205). The reactions were monitored over time by gas chromatography, and the intermediates of the one-pot cascade biotransformation involving reductions of C=C and C=O bonds as well as the Baeyer–Villiger oxidation were identified and quantified. The Baeyer–Villiger monooxygenase (BVMO) enzyme was predominant, and all three substrates were completely converted into ?-CL. Furthermore, the whole cells of Geotrichum candidum were recycled and reutilized in the biotransformation of cyclohexanone, producing ?-CL at least six consecutive times without a significant loss of activity, reaction yields or product purity. 相似文献
12.
Shaofeng Rong Shulin Yang Baoguo Cai Shimin Guan Jingwen Wang 《Biocatalysis and Biotransformation》2017,35(2):96-102
A number of yeast species can transform ricinoleic acid into γ-decalactone, a high-value compound with fruity aroma, through β-oxidation. This study investigated the effect of l-carnitine on γ-decalactone production by Saccharomyces cerevisiae MF013 to increase the β-oxidation rate. Results showed that l-carnitine shortened the biotransformation period by approximately 10?h and increased γ-decalactone production by 19.5%. γ-Caprolactone, γ-octalactone, and γ-dodecalactone were separately added to the medium to prevent γ-decalactone degradation by yeast cells at the end of biotransformation. γ-Octalactone competitively inhibited γ-decalactone from binding to lactonase, resulting in an 11% increase in γ-decalactone production. This research proposed an effective approach to improve the γ-decalactone production rate, shorten the biotransformation period, and suppress the γ-decalactone degradation in S. cerevisiae. 相似文献
13.
Y G Garza M G Rodríguez C L Hernández J M Rodríguez 《Journal of industrial microbiology & biotechnology》2000,25(5):225-228
In an attempt to clarify the function of l-aspartic acid and culture conditions in aspartate ammonia lyase induction, experiments were carried out on aspartase formation
in Bacillus cereus cells. The enzyme was produced by microorganisms in response to l-aspartic acid, which is catabolized by direct deamination to fumarate. Enzyme synthesis by B. cereus was associated with physiological growth stages, which was confirmed by use of the protein synthesis inhibitor, chloramphenicol,
whereas it did not influence synthesis when it was added directly to the reactor batch containing a biotransformation system.
Aspartase activity was evaluated in a batch reactor by biotransformation of fumaric acid into l-aspartic acid catalyzed by whole B. cereus cells. The culture medium for the strain was optimized, which increased the initial aspartase activity threefold. B. cereus cells showed optimal aspartase activity at late log phase. Journal of Industrial Microbiology & Biotechnology (2000) 25, 225–228.
Received 02 December 1999/ Accepted in revised form 09 August 2000 相似文献
14.
Kinetic model for biotransformation of digitoxin in plant cell suspension culture ofDigitalis lanata
Jeong-Woo Choi Young-Kee Kim Hyun-Kyu Park Won Hong Lee Dong-Il Kim 《Biotechnology and Bioprocess Engineering》1999,4(4):281-286
Batch suspension cultures ofDigitalis lanata plant cell were performed to investigate the biotransformation of digitoxin.Digitalis lanata K3OHD plant cells were used to biotransform digitoxin into deacetyllanatoside C. A kinetic model was proposed to describe
cell growth, substrate consumption, depletion of digitoxin, formation and depletion of digoxin and purpureaglycoside A, and
formation of deacetyllanatoside C. The digoxin and purpureaglycoside A are intermediates of deacetyllanatoside C formation
from digitoxin. Interactions between extracellular and intracellular compounds were considered. The proposed model could accurately
predict cell growth, substrate consumption and product synthesis. And it can provide a useful framework for quantitative analysis
of biotransformation in a plant cell culture system. 相似文献
15.
Giovanni Gontijo de Souza Cleber Paulo Andrada Anconi Sjef Cornelissen Wagner Batista De Almeida Hélio Ferreira Dos Santos Isabel Cristina Pereira Fortes Jacqueline Aparecida Takahashi 《Journal of industrial microbiology & biotechnology》2009,36(8):1023-1027
The biotransformation of 1R-(−)-camphorquinone, achieved by growing cells of four fungi species isolated from soil (Mucor plumbeus, Lecanicillium muscarium, Thamnostylum sp. and Syncephalastrum racemosum), was investigated in optimized culture media for each species. Fungi were grown aerobically under shaking and their activities
with respect to camphorquinone were monitored for 20 days by gas chromatography coupled to mass spectrometry (GCMS). Camphorquinone
was found to be stable in control flasks throughout the experiment. The most interesting results were found for M. plumbeus, which was only able to perform monoreduction of camphorquinone when cultivated on a glucose–peptone–yeast extract medium.
Large-scale experiments were set up and the camphorquinone biotransformation products formed by M. plumbeus were purified by column chromatography and identified by 1H and 13C nuclear magnetic resonance (NMR). Theoretical calculations were employed as a complementary technique to unambiguously identify
the biotransformation products. These findings suggest that M. plumbeus could be of great use for the selective reduction of camphorquinone and related compounds. 相似文献
16.
Whole‐cell biotransformation of oleanolic acid by free and immobilized cells of Nocardia iowensis: Characterization of new metabolites
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Benjamin Ludwig Doris Geib Christiane Haas Juliane Steingroewer Thomas Bley Kai Muffler Roland Ulber 《Engineering in Life Science》2015,15(1):108-115
In this study, Nocardia iowensis was used to transform oleanolic acid (OA) into oleanane derivatives. The first derivative, which was found after 24 h of cultivation, was the known and already described OA methyl ester. After 1 week, two other derivatives (oleanonic acid methyl ester and an unknown metabolite) were identified as new products of a biotransformation by N. iowensis. These oleanane metabolites were characterized by HPLC, HPLC‐ESI‐MS, and HPLC‐1H NMR spectroscopy. The biotransformation was performed by suspended and immobilized cells (ICs) of N. iowensis. Cells immobilized in alginate beads were used in order to prepare a continuous process. The substrate uptake of free and ICs was similar, whereas the peak area of OA methyl ester of the ICs was only about 10% of the native cells. However, the final product (oleanonic acid methyl ester) concentrations were similar in both approaches, whereas the unknown metabolite 3 was only detected transiently in the medium of ICs. Based on these results, a new biosynthetic pathway for the biotechnological production of oleanonic acid methyl ester is proposed. 相似文献
17.
Natural products and enzymes from plant cell cultures 总被引:3,自引:0,他引:3
J. Stöckigt P. Obitz H. Falkenhagen R. Lutterbach S. Endreß 《Plant Cell, Tissue and Organ Culture》1995,43(2):97-109
Plants represent an unlimited source of natural products. Many of the recently detected phytochemicals exhibit remarkable bioactivities, ranging from anticancer activity, phosphodiesterase inhibition to cytotoxicity against HIV-infected cells. Cultivated plant cells produce at their unorganized, dedifferentiated stage secondary metabolites, but in very different amounts in so far as new compounds are concerned. In fact, more than 140 novel natural products are presently known from plant cell cultures, which also include new metabolites formed by biotransformation. The biotransformation capacity of suspended cells is described and recent high yielding transformations, like the formation of arbutin by hydroquinone-transformation withRauwolfia cells are discussed. As an example of alkaloid production by cell suspensions, the pattern of monoterpenoid indole alkaloids of the Indian medicinal plantRauwolfia serpentina Benth. is described and the so far 30 identified compounds are divided into eight groups which are biosynthetically closely related. Some of the key biosynthetic reactions leading to theRauwolfia alkaloids are discussed and an overview of the enzymes involved in the formation of the alkaloid ajmaline and proteins catalyzing side reactions of the ajmaline pathway are given. 相似文献
18.
The biotransformation of 6,7-epoxygeraniol by resting cells of selected fungi was investigated. The main product obtained from the transformation in Rhodotorula glutinis and R. marina cultures was 6,7-epoxynerol (5–48% of chloroform extracts), whereas Saccharomyces cerevisiae, Candida parapsilosis and C. kefyr reduced this substrate to 6,7-epoxycitronellol (30–33% of chloroform extracts). Cultures of Yarrowia lipolytica, Botrytis cinerea and S. cerevisiae promoted the cyclisation of 6,7-epoxygeraniol to 2-methyl-2-(2-hydroxyethyl)-5-(2-hydroxyprop-2-yl)tetrahydrofuran (11–99% of chloroform extracts). The biotransformation of 6,7-epoxynerol was also investigated. However, none of the tested micro-organisms converted this compound. 相似文献
19.
The increasing commercial demand for L-carnitine has led to a multiplication of efforts to improve its production with bacteria.
The use of different cell environments, such as growing, resting, permeabilized, dried, osmotically stressed, freely suspended
and immobilized cells, to maintain enzymes sufficiently active for L-carnitine production is discussed in the text. The different
cell states of enterobacteria, such as Escherichia coli and Proteus sp., which can be used to produce L-carnitine from crotonobetaine or D-carnitine as substrate, are analyzed. Moreover, the combined
application of both bioprocess and metabolic engineering has allowed a deeper understanding of the main factors controlling
the production process, such as energy depletion and the alteration of the acetyl-CoA/CoA ratio which are coupled to the end
of the biotransformation. Furthermore, the profiles of key central metabolic activities such as the TCA cycle, the glyoxylate
shunt and the acetate metabolism are seen to be closely interrelated and affect the biotransformation efficiency. Although
genetically modified strains have been obtained, new strain improvement strategies are still needed, especially in Escherichia coli as a model organism for molecular biology studies. This review aims to summarize and update the state of the art in L-carnitine
production using E. coli and Proteus sp, emphasizing the importance of proper reactor design and operation strategies, together with metabolic engineering aspects
and the need for feed-back between wet and in silico work to optimize this biotransformation. 相似文献
20.
Kirsten Schroer Bruno Zelic Marco Oldiges Stephan Lütz 《Biotechnology and bioengineering》2009,104(2):251-260
For redox reactions catalyzed by microbial cells the analysis of involved cofactors is of special interest since the availability of cofactors such as NADH or NADPH is often limiting and crucial for the biotransformation efficiency. The measurement of these cofactors has usually been carried out using spectrophotometric cycling assays. Today LC‐MS/MS methods have become a valuable tool for the identification and quantification of intracellular metabolites. This technology has been adapted to measure all four nicotinamide cofactors (NAD, NADP, NADH, and NADPH) during a whole cell biotransformation process catalyzed by recombinant Escherichia coli cells. The cells overexpressing an alcohol dehydrogenase from Lactobacillus brevis were used for the reduction of methyl acetoacetate (MAA) with substrate‐coupled cofactor regeneration by oxidation of 2‐propanol. To test the reliability of the measurement the data were evaluated using a process model. This model was derived using the measured concentrations of reactants and cofactors for initiation as well as the kinetic constants from in vitro measurements of the isolated enzyme. This model proves to be highly effective in the process development for a whole cell redox biotransformation in predicting both the right concentrations of cofactors and reactants in a batch and in a CSTR process as well as the right in vivo expression level of the enzyme. Moreover, a sensitivity analysis identifies the cofactor regeneration reaction as the limiting step in case for the reduction of MAA to the corresponding product (R)‐methyl 3‐hydroxybutyrate. Using the combination of in vitro enzyme kinetic measurements, measurements of cofactors and reactants and an adequate model initiated by intracellular concentrations of all involved reactants and cofactors the whole cell biotransformation process can be understood quantitatively. Biotechnol. Bioeng. 2009; 104: 251–260 © 2009 Wiley Periodicals, Inc. 相似文献