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1.
Gopinath V Murali A Dhar KS Nampoothiri KM 《Applied microbiology and biotechnology》2012,93(1):95-106
Corynebacterium glutamicum, the industrial microbe traditionally used for the production of amino acids, proved its value for the fermentative production
of diverse products through genetic/metabolic engineering. A successful demonstration of the heterologous expression of arabinose
and xylose utilization genes made them interesting biocatalysts for pentose fermentation, which are the main components in
lignocellulosic hydrolysates. Its ability to withstand substantial amount of general growth inhibitors like furfurals, hydroxyl
methyl furfurals and organic acids generated from the acid/alkali hydrolysis of lignocellulosics in growth arrested conditions
and its ability to produce amino acids like glutamate and lysine in acid hydrolysates of rice straw and wheat bran, indicate
the future prospective of this bacterium as a potent biocatalyst in fermentation biotechnology. However, the efforts so far
on these lines have not yet been reviewed, and hence an attempt is made to look into the efficacy and prospects of C. glutamicum to utilize the normally non-fermentable pentose sugars from lignocellulosic biomass for the production of commodity chemicals. 相似文献
2.
K. Sonntag J. Schwinde A. A. de Graaf A. Marx B. J. Eikmanns W. Wiechert H. Sahm 《Applied microbiology and biotechnology》1995,44(3-4):489-495
The carbon flux distribution in the central metabolism of Corynebacterium glutamicum was studied in batch cultures using [1-13C]- and [6-13C]glucose as substrate during exponential growth as well as during overproduction of l-lysine and l-glutamate. Using the 13C NMR data in conjunction with stoichiometric metabolite balances, molar fluxes were quantified and normalised to the glucose uptake rate, which was set to 100. The normalised molar flux via the hexose monophosphate pathway was 40 during exponential growth, whereas it was only 17 during l-glutamate production. During l-lysine production, the normalised hexose monophosphate pathway flux was elevated to 47. Thus, the carbon flux via this pathway correlated with the NADPH demand for bacterial growth and l-lysine overproduction. The normalised molar flux in the tricarboxylic acid cycle at the level of 2-oxoglutarate dehydrogenase was 100 during exponential growth and 103 during l-lysine secretion. During l-glutamate formation, the normalised flux through the tricarboxylic acid cycle was reduced to 60. In contrast to earlier NMR studies with C. glutamicum, no significant activity of the glyoxylate pathway could be detected. All experiments indicated a strong in vivo flux from oxaloacetate back to phosphoenolpyruvate and/or pyruvate, which might be due to phosphoenolpyruvate carboxykinase activity in C. glutamicum. 相似文献
3.
4.
In order to improve the production rate of l-lysine, a mutant of Corynebacterium glutamicum ATCC 21513 was cultivated in complex medium with gluconate and glucose as mixed carbon sources. In a batch culture, this
strain was found to consume gluconate and glucose simultaneously. In continuous culture at dilution rates ranging from 0.2
h−1 to 0.25 h−1, the specific l-lysine production rate increased to 0.12 g g−1 h−1 from 0.1 g g−1 h−1, the rate obtained with glucose as the sole carbon source [Lee et al. (1995) Appl Microbiol Biotechnol 43:1019–1027]. It
is notable that l-lysine production was observed at higher dilution rates than 0.4 h−1, which was not observed when glucose was the sole carbon source. The positive effect of gluconate was confirmed in the shift
of the carbon source from glucose to gluconate. The metabolic transition, which has been characterized by decreased l-lysine production at the higher glucose uptake rates, was not observed when gluconate was added. These results demonstrate
that the utilization of gluconate as a secondary carbon source improves the maximum l-lysine production rate in the threonine-limited continuous culture, probably by relieving the limiting factors in the lysine
synthesis rate such as NADPH supply and/or phosphoenolpyruvate availability.
Received: 16 May 1997 / Received revision: 28 August 1997 / Accepted: 29 August 1997 相似文献
5.
Blombach B Schreiner ME Moch M Oldiges M Eikmanns BJ 《Applied microbiology and biotechnology》2007,76(3):615-623
Intracellular precursor supply is a critical factor for amino acid productivity of Corynebacterium glutamicum. To test for the effect of improved pyruvate availability on l-lysine production, we deleted the aceE gene encoding the E1p enzyme of the pyruvate dehydrogenase complex (PDHC) in the l-lysine-producer C. glutamicum DM1729 and characterised the resulting strain DM1729-BB1 for growth and l-lysine production. Compared to the host strain, C. glutamicum DM1729-BB1 showed no PDHC activity, was acetate auxotrophic and, after complete consumption of the available carbon sources
glucose and acetate, showed a more than 50% lower substrate-specific biomass yield (0.14 vs 0.33 mol C/mol C), an about fourfold
higher biomass-specific l-lysine yield (5.27 vs 1.23 mmol/g cell dry weight) and a more than 40% higher substrate-specific l-lysine yield (0.13 vs 0.09 mol C/mol C). Overexpression of the pyruvate carboxylase or diaminopimelate dehydrogenase genes
in C. glutamicum DM1729-BB1 resulted in a further increase in the biomass-specific l-lysine yield by 6 and 56%, respectively. In addition to l-lysine, significant amounts of pyruvate, l-alanine and l-valine were produced by C. glutamicum DM1729-BB1 and its derivatives, suggesting a surplus of precursor availability and a further potential to improve l-lysine production by engineering the l-lysine biosynthetic pathway.
This study is dedicated to Prof. Dr. Hermann Sahm on the occasion of his 65th birthday. 相似文献
6.
H. Sahm 《Folia microbiologica》1995,40(1):23-30
The Gram-positive bacteriumCorynebacterium glutamicum is used for the industrial production of amino acids,e.g. ofl-glutamate andl-lysine. By cloning and expressing the various genes of thel-lysine pathway inC. glutamicum we could demonstrate that an increase of the flux ofl-4-aspartaldehydate tol-lysine could be obtained in strains with increased dihydro-dipicolinate synthase activity. Recently we detected that inC. glutamicum two pathways exist for the synthesis ofdl-2,6-diaminopimelate andl-lysine. Mutants defective in one pathway are still able to synthesize enoughl-lysine for growth but thel-lysine secretion is reduced to 50–70%. Using NMR-spectroscopy we could calculate how much of thel-lysine secreted into the medium is synthesizedvia the one and the other pathway. Amplification of the feedback-inhibition-insensitive-homoserine dehydrogenase and homoserine
kinase in a highl-lysine-overproducing strain made it possible to channell of the carbon flow from the intermediate 4-aspartaldehydate toward
homoserine, resulting in a high accumulation ofl-threonine. For a further flux froml-threonine tol-isoleucine the allosteric control of threonine dehydratase was eliminated.
Dedicated to Dr. Z. Vaněk on the occasion of his 70th birthday
Presented at theIUMS Congresses '94-7th International Congress of Bacteriology and Applied Microbiology Division, Prague, July 3–8, 1994 (Bacteriological Symposium BS-12Regulation of Microbial Product Overproduction). 相似文献
7.
Lactic acid production from xylose by the fungus Rhizopus oryzae 总被引:1,自引:1,他引:0
Lignocellulosic biomass is considered nowadays to be an economically attractive carbohydrate feedstock for large-scale fermentation of bulk chemicals such as lactic acid. The filamentous fungus Rhizopus oryzae is able to grow in mineral medium with glucose as sole carbon source and to produce optically pure l(+)-lactic acid. Less is known about the conversion by R. oryzae of pentose sugars such as xylose, which is abundantly present in lignocellulosic hydrolysates. This paper describes the conversion of xylose in synthetic media into lactic acid by ten R. oryzae strains resulting in yields between 0.41 and 0.71 g g−1. By-products were fungal biomass, xylitol, glycerol, ethanol and carbon dioxide. The growth of R. oryzae CBS 112.07 in media with initial xylose concentrations above 40 g l−1 showed inhibition of substrate consumption and lactic acid production rates. In case of mixed substrates, diauxic growth was observed where consumption of glucose and xylose occurred subsequently. Sugar consumption rate and lactic acid production rate were significantly higher during glucose consumption phase compared to xylose consumption phase. Available xylose (10.3 g l−1) and glucose (19.2 g l−1) present in a mild-temperature alkaline treated wheat straw hydrolysate was converted subsequently by R. oryzae with rates of 2.2 g glucose l−1 h−1 and 0.5 g xylose l−1 h−1. This resulted mainly into the product lactic acid (6.8 g l−1) and ethanol (5.7 g l−1). 相似文献
8.
Carbohydrates exclusively serve as feedstock for industrial amino acid production with Corynebacterium glutamicum. Due to the industrial interest, knowledge about the pathways for carbohydrate metabolization in C. glutamicum steadily increases, enabling the rational design of optimized strains and production processes. In this review, we provide
an overview of the metabolic pathways for utilization of hexoses (glucose, fructose), disaccharides (sucrose, maltose), pentoses
(d-ribose, l-arabinose, d-xylose), gluconate, and β-glucosides present in C. glutamicum. Recent approaches of metabolic engineering of l-lysine production strains based on the known pathways are described and evaluated with respect to l-lysine yields. 相似文献
9.
We engineered a Corynebacterium glutamicum strain displaying α-amylase from Streptococcus bovis 148 (AmyA) on its cell surface to produce amino acids directly from starch. We used PgsA from Bacillus subtilis as an anchor protein, and the N-terminus of α-amylase was fused to the PgsA. The genes of the fusion protein were integrated
into the homoserine dehydrogenase gene locus on the chromosome by homologous recombination. l-Lysine fermentation was carried out using C. glutamicum displaying AmyA in the growth medium containing 50 g/l soluble starch as the sole carbon source. We performed l-lysine fermentation at various temperatures (30–40°C) and pHs (6.0–7.0), as the optimal temperatures and pHs of AmyA and
C. glutamicum differ significantly. The highest l-lysine yield was recorded at 30°C and pH 7.0. The amount of soluble starch was reduced to 18.29 g/l, and 6.04 g/l l-lysine was produced in 24 h. The l-lysine yield obtained using soluble starch as the sole carbon source was higher than that using glucose as the sole carbon
source after 24 h when the same amount of substrates was added. The results shown in the current study demonstrate that C. glutamicum displaying α-amylase has a potential to directly convert soluble starch to amino acids. 相似文献
10.
Trametes versicolor was shown to produce extracellular laccase during surface cultivation on glucose, wheat straw and beech wood. Growth on both
wheat straw and beech wood led to an increase as high as 3.5-fold in extracellular laccase activity, in comparison with growth
on glucose. The corresponding yields in fungal biomass reached only about 20% of the value obtained on glucose. Manganese
peroxidase activity␣appeared during growth on wheat straw and beech wood. Mycelia grown on glucose, wheat straw and beech
wood also showed intracellular laccase activities, monitored with 2,6-dimethoxyphenol, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic
acid), 4-hydroxy-3,5-dimethoxybenzaldehyde azine (syringaldazine) and 3,4-dihydroxyphenylalanine (l-DOPA). Assaying intracellular laccase with 2,6-dimethoxyphenol, syringaldazine and l-DOPA showed the maximum oxidation rates to be at pH values different from those producing maximum oxidation rates with extracellular
laccase. In each case most of the total laccase activity was recovered from the culture filtrates. Growth on wheat straw and
beech wood led to increased values for both extra- and intracellular laccase activities, based on fungal dry weight, in comparison
with growth on glucose.
Received: 18 July 1996 / Received revision: 19 November 1996 / Accepted: 23 November 1996 相似文献
11.
Xylose utilisation by recombinant strains of Saccharomyces cerevisiae on different carbon sources 总被引:1,自引:0,他引:1
van Zyl WH Eliasson A Hobley T Hahn-Hägerdal B 《Applied microbiology and biotechnology》1999,52(6):829-833
Autoselective xylose-utilising strains of Saccharomyces cerevisiae expressing the xylose reductase (XYL1) and xylitol dehydrogenase (XYL2) genes of Pichia stipitis were constructed by replacing the chromosomal FUR1 gene with a disrupted fur1::LEU2 allele. Anaerobic fermentations with 80 g l−1
d-xylose as substrate showed a twofold higher consumption of xylose in complex medium compared to defined medium. The xylose
consumption rate increased a further threefold when 20 g l−1
d-glucose or raffinose was used as co-substrate together with 50 g l−1
d-xylose. Xylose consumption was higher with raffinose as co-substrate than with glucose (85% versus 71%, respectively) after
82 h fermentations. A high initial ethanol concentration and moderate levels of glycerol and acetic acid accompanied glucose
as co-substrate, whereas the ethanol concentration gradually increased with raffinose as co-substrate with no glycerol and
much less acetic acid formation.
Received: 12 March 1999 / Received revision: 31 June 1999 / Accepted: 5 July 1999 相似文献
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13.
Yang Guo Qiaojuan Yan Zhengqiang Jiang Chao Teng Xinlei Wang 《Journal of industrial microbiology & biotechnology》2010,37(11):1137-1143
The aim of this study is to investigate production of l-lactic acid from sucrose and corncob hydrolysate by the newly isolated R. oryzae GY18. R. oryzae GY18 was capable of utilizing sucrose as a sole source, producing 97.5 g l−1
l-lactic acid from 120 g l−1 sucrose. In addition, the strain was also efficiently able to utilize glucose and/or xylose to produce high yields of l-lactic acid. It was capable of producing up to 115 and 54.2 g l−1 lactic acid with yields of up to 0.81 g g−1 glucose and 0.90 g g−1 xylose, respectively. Corncob hydrolysates obtained by dilute acid hydrolysis and enzymatic hydrolysis of the cellulose-enriched
residue were used for lactic acid production by R. oryzae GY18. A yield of 355 g lactic acid per kg corncobs was obtained after 72 h incubation. Therefore, sucrose and corncobs could
serve as potential sources of raw materials for efficient production of lactic acid by R. oryzae GY18. 相似文献
14.
Microbial production of L -glutamate and L -glutamine by recombinant Corynebacterium glutamicum harboring Vitreoscilla hemoglobin gene vgb 总被引:1,自引:0,他引:1
Liu Q Zhang J Wei XX Ouyang SP Wu Q Chen GQ 《Applied microbiology and biotechnology》2008,77(6):1297-1304
Vitreoscilla hemoglobin (VHb) gene vgb equipped with a native promoter Pvgb or a tac promoter Ptac was introduced into Corynebacterium glutamicum ATCC14067, respectively. Ptac was proven to be more suitable for expressing VHb protein in higher concentration in both Escherichia coli and C. glutamicum strains compared with the native vgb promoter Pvgb. VHb-expressing C. glutamicum exhibited higher oxygen uptake rate and enhanced cell growth. Recombinant C. glutamicum harboring vgb gene equipped with Ptac promoter produced 23% more l-glutamate in shake-flask culture and grew to 30% more cell density and formed 22% more l-glutamate in fermentor studies compared with the wild-type strain. When a site-directed mutagenesis in which Tyr405 was replaced
by a phenylalanine residue (Y405F) was performed on glutamine synthesis gene, recombinant C. glutamicum overexpressing the mutated gene glnA′ was able to produce l-glutamine effectively. Co-expression of vgb and glnA′ genes in C. glutamicum produced 17 g/l l-glutamine in shake flask culture, approximately 30% more than that produced by the recombinant harboring only glnA′ gene. In fermentor cultivation, the recombinant yielded 25% more cells and produced 40.5 g/l l-glutamine. In this study, it was clearly demonstrated that VHb significantly enhanced cell growth, l-glutamate, and l-glutamine production by recombinant C. glutamicum. 相似文献
15.
16.
Wenjuan Yao Xiaozhao Deng Hui Zhong Miao Liu Pu Zheng Zhihao Sun Yun Zhang 《Journal of industrial microbiology & biotechnology》2009,36(7):911-921
Corynebacterium glutamicum strains are used for the fermentative production of l-glutamate. Five C. glutamicum deletion mutants were isolated by two rounds of selection for homologous recombination and identified by Southern blot analysis.
The growth, glucose consumption and glutamate production of the mutants were analyzed and compared with the wild-type ATCC
13032 strain. Double disruption of dtsR1 (encoding a subunit of acetyl-CoA carboxylase complex) and pyc (encoding pyruvate carboxylase) caused efficient overproduction of l-glutamate in C. glutamicum; production was much higher than that of the wild-type strain and ΔdtsR1 strain under glutamate-inducing conditions. In the absence of any inducing conditions, the amount of glutamate produced by
the double-deletion strain ΔdtsR1Δpyc was more than that of the mutant ΔdtsR1. The activity of phosphoenolpyruvate carboxylase (PEPC) was found to be higher in the ΔdtsR1Δpyc strain than in the ΔdtsR1 strain and the wild-type strain. Therefore, PEPC appears to be an important anaplerotic enzyme for glutamate synthesis in
ΔdtsR1 derivatives. Moreover, this conclusion was confirmed by overexpression of ppc and pyc in the two double-deletion strains (ΔdtsR1Δppc and ΔdtsR1Δpyc), respectively. Based on the data generated in this investigation, we suggest a new method that will improve glutamate production
strains and provide a better understanding of the interaction(s) between the anaplerotic pathway and fatty acid synthesis. 相似文献
17.
J. Custot Jean-Luc Boucher Sandrine Vadon Catherine Guedes Sylvie Dijols Marcel Delaforge Daniel Mansuy 《Journal of biological inorganic chemistry》1996,1(1):73-82
The effects of various compounds bearing an N-OH group such as N-hydroxy-guanidines, amidoximes, and hydroxylamines, on bovine and rat liver arginases was studied. Some of these compounds
with an l-α-amino acid function at an appropriate distance from the N-OH group acted as strong competitive liver arginase inhibitors,
displaying Ki values between 4 and 150 μM. Two compounds, N
ε-hydroxy-l-lysine and N
ω-hydroxy-d,l-indospicine, which exhibited Ki values of 4 and 20 μM (at pH 7.4), were the most potent inhibitors of arginase described
to date. The distance between the α-amino acid and N-OH functions appeared to be crucial for potent inhibition of arginase,
as N
δ-hydroxy-l-ornithine, which has one -CH2 group less than N
ε-hydroxy-l-lysine, exhibited a 37-fold higher Ki value than N
ε-hydroxy-l-lysine. Based on these results, a model for the interaction of N
ω-hydroxyamino-l-α-amino acids with the arginase active site is proposed. This model involves the binding of the N-OH group of the inhibitors
to the arginase Mn(II) center and suggests that N
ε-hydroxy-l-lysine is a good transition state analog of arginase. 相似文献
18.
Mohamed Guerfali Moncef Chaabouni Ali Gargouri Hafedh Belghith 《Applied microbiology and biotechnology》2010,85(5):1361-1372
This study is an application of an experimental design methodology for the optimization of the culture conditions of α-l-arabinofuranosidase production by Talaromyces thermophilus. Wheat bran and yeast extract were first selected as the best carbon and nitrogen sources, respectively, for enzyme production.
A Plackett–Burman design was then used to evaluate the effects of eight variables. Statistical analyses showed that while
pH had a negative effect on α-l-arabinofuranosidase production, wheat bran and MgSO4 had a significantly positive effect. The values of the latter three parameters were further optimised using a central composite
design and a response surface methodology. The experimental results were fitted to a second-order polynomial model that yielded
a determination coefficient of R
2 = 0.91. The statistical output showed that the linear and quadric terms of the three variables had significant effects. Using
optimal conditions, the experimental value of α-l-arabinofuranosidase activity produced was very close to the model-predicted value. The optimal temperature and pH of enzyme
activity were 55 °C and 7.0, respectively. This enzyme was very stable over a considerable pH range from 4 to 9. The crude
enzyme of T. thermophilus rich in α-l-arabinofuranosidase was also used for saccharification of lignocellulosic materials and arabinose production. 相似文献
19.
Okino S Suda M Fujikura K Inui M Yukawa H 《Applied microbiology and biotechnology》2008,78(3):449-454
In mineral salts medium under oxygen deprivation, Corynebacterium glutamicum exhibits high productivity of l-lactic acid accompanied with succinic and acetic acids. In taking advantage of this elevated productivity, C. glutamicum was genetically modified to produce d-lactic acid. The modification involved expression of fermentative d-lactate dehydrogenase (d-LDH)-encoding genes from Escherichia coli and Lactobacillus delbrueckii in l-lactate dehydrogenase (l-LDH)-encoding ldhA-null C. glutamicum mutants to yield strains C. glutamicum ΔldhA/pCRB201 and C. glutamicum ΔldhA/pCRB204, respectively. The productivity of C. glutamicum ΔldhA/pCRB204 was fivefold higher than that of C. glutamicum ΔldhA/pCRB201. By using C. glutamicum ΔldhA/pCRB204 cells packed to a high density in mineral salts medium, up to 1,336 mM (120 g l−1) of d-lactic acid of greater than 99.9% optical purity was produced within 30 h. 相似文献
20.