scholarly journals Engineering of a Xylose Metabolic Pathway in Corynebacterium glutamicum

2006 ◽  
Vol 72 (5) ◽  
pp. 3418-3428 ◽  
Author(s):  
Hideo Kawaguchi ◽  
Alain A. Vert�s ◽  
Shohei Okino ◽  
Masayuki Inui ◽  
Hideaki Yukawa
Keyword(s):  
Carbon Source ◽  
Corynebacterium Glutamicum ◽  
Xylose Isomerase ◽  
Mineral Medium ◽  
Gene Encoding ◽  
Xylose Consumption ◽  
E Coli ◽  
High Copy Number Plasmid ◽  
Sugar Mixture ◽  
Pentose Sugar

ABSTRACT The aerobic microorganism Corynebacterium glutamicum was metabolically engineered to broaden its substrate utilization range to include the pentose sugar xylose, which is commonly found in agricultural residues and other lignocellulosic biomass. We demonstrated the functionality of the corynebacterial xylB gene encoding xylulokinase and constructed two recombinant C. glutamicum strains capable of utilizing xylose by cloning the Escherichia coli gene xylA encoding xylose isomerase, either alone (strain CRX1) or in combination with the E. coli gene xylB (strain CRX2). These genes were provided on a high-copy-number plasmid and were under the control of the constitutive promoter trc derived from plasmid pTrc99A. Both recombinant strains were able to grow in mineral medium containing xylose as the sole carbon source, but strain CRX2 grew faster on xylose than strain CRX1. We previously reported the use of oxygen deprivation conditions to arrest cell replication in C. glutamicum and divert carbon source utilization towards product production rather than towards vegetative functions (M. Inui, S. Murakami, S. Okino, H. Kawaguchi, A. A. Vert�s, and H. Yukawa, J. Mol. Microbiol. Biotechnol. 7:182-196, 2004). Under these conditions, strain CRX2 efficiently consumed xylose and produced predominantly lactic and succinic acids without growth. Moreover, in mineral medium containing a sugar mixture of 5% glucose and 2.5% xylose, oxygen-deprived strain CRX2 cells simultaneously consumed both sugars, demonstrating the absence of diauxic phenomena relative to the new xylA-xylB construct, albeit glucose-mediated regulation still exerted a measurable influence on xylose consumption kinetics.

Characterization and Functional Expression of Xylose Isomerase from Thermus thermophilus

2013 ◽  
Vol 641-642 ◽  
pp. 919-922
Author(s):  
An Gen Lu ◽  
Ze Xi Yang ◽  
Fei Wang ◽  
Lang Xu ◽  
Wen Ying Deng ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Specific Activity ◽  
Thermus Thermophilus ◽  
Xylose Isomerase ◽  
Functional Expression ◽  
Future Application ◽  
Gene Encoding ◽  
E Coli ◽  
Rate Limiting ◽  
Pentose Sugars

Ethanol produced from hexose and pentose sugars hydrolysated by lignocellulose is an environment-friendly alternative to fossil fuels. Xylose isomerase is the major rate-limiting enzyme in the ethanol synthesis biologically pathway of xylose fermentation. In present study, xylA gene encoding xylose isomerase was cloned from Thermus thermophilus and overexpressed in E. coli BL21. Purified recombinant enzyme was used to study the enzymatic characterization. Specific activity of recombinant PDOR was 19.6 U/mg. Optimal temperature and pH were 80 °C, 8.0, respectively. Km and Vmax values were 15.9 mM, 22.8 U/mg. This research may form a basis for the future application of xylose isomerase.

Cloning and analysis of the aroB gene encoding dehydroquinate synthase from Corynebacterium glutamicum

1999 ◽  
Vol 45 (10) ◽  
pp. 885-890 ◽  
Author(s):  
Min-Ah Han ◽  
Heung-Shick Lee ◽  
Choong-Ill Cheon ◽  
Kyung-Hee Min ◽  
Myeong-Sok Lee
Keyword(s):  
Escherichia Coli ◽  
Corynebacterium Glutamicum ◽  
Auxotrophic Mutant ◽  
Gene Products ◽  
Gene Encoding ◽  
Reading Frame ◽  
E Coli ◽  
Dna Library ◽  
Genomic Dna Library ◽  
Dehydroquinate Synthase

The aroB gene encoding dehydroquinate synthase of Corynebacterium glutamicum has been cloned by complementation of an aro auxotrophic mutant of Escherichia coli with the genomic DNA library. The recombinant plasmid contained a 1.4-kb fragment that complemented the Escherichia coli dehydroquinate-synthase-deficient mutant. The nucleotide sequences of the subcloned DNA has been determined. The sequences contain an open reading frame of 360 codons, from which a protein with a molecular mass of about 38 kDa could be predicted. This is consistent with the size of the AroB protein expressed in E. coli. Alignment of different prokaryotic and eukaryotic aroB gene products reveals an overall identity ranging from 29 to 57% and the presence of several highly conserved regions.Key words: Corynebacterium glutamicum, aromatic amino acid biosynthetic gene, dehydroquinate synthase, aroB gene.

scholarly journals Xylulokinase Overexpression in Two Strains ofSaccharomyces cerevisiae Also Expressing Xylose Reductase and Xylitol Dehydrogenase and Its Effect on Fermentation of Xylose and Lignocellulosic Hydrolysate

2001 ◽  
Vol 67 (9) ◽  
pp. 4249-4255 ◽  
Author(s):  
Björn Johansson ◽  
Camilla Christensson ◽  
Timothy Hobley ◽  
Bärbel Hahn-Hägerdal
Keyword(s):  
Ethanol Yield ◽  
Xylose Reductase ◽  
Xylitol Dehydrogenase ◽  
Host Strain ◽  
Lignocellulosic Hydrolysate ◽  
Xylose Consumption ◽  
Sugar Mixture ◽  
Pentose Sugar ◽  
Ethanol Yields ◽  
Ethanol Producer

ABSTRACT Fermentation of the pentose sugar xylose to ethanol in lignocellulosic biomass would make bioethanol production economically more competitive. Saccharomyces cerevisiae, an efficient ethanol producer, can utilize xylose only when expressing the heterologous genes XYL1 (xylose reductase) andXYL2 (xylitol dehydrogenase). Xylose reductase and xylitol dehydrogenase convert xylose to its isomer xylulose. The geneXKS1 encodes the xylulose-phosphorylating enzyme xylulokinase. In this study, we determined the effect ofXKS1 overexpression on two different S. cerevisiae host strains, H158 and CEN.PK, also expressingXYL1 and XYL2. H158 has been previously used as a host strain for the construction of recombinant xylose-utilizing S. cerevisiae strains. CEN.PK is a new strain specifically developed to serve as a host strain for the development of metabolic engineering strategies. Fermentation was carried out in defined and complex media containing a hexose and pentose sugar mixture or a birch wood lignocellulosic hydrolysate.XKS1 overexpression increased the ethanol yield by a factor of 2 and reduced the xylitol yield by 70 to 100% and the final acetate concentrations by 50 to 100%. However, XKS1overexpression reduced the total xylose consumption by half for CEN.PK and to as little as one-fifth for H158. Yeast extract and peptone partly restored sugar consumption in hydrolysate medium. CEN.PK consumed more xylose but produced more xylitol than H158 and thus gave lower ethanol yields on consumed xylose. The results demonstrate that strain background and modulation of XKS1 expression are important for generating an efficient xylose-fermenting recombinant strain of S. cerevisiae.

scholarly journals Efficient anaerobic consumption of D-xylose by E. coli BL21(DE3) via xylR adaptive mutation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jung Min Heo ◽  
Hyun Ju Kim ◽  
Sang Jun Lee
Keyword(s):  
Consumption Rate ◽  
Xylose Isomerase ◽  
Fold Increase ◽  
Adaptive Mutation ◽  
Growth Media ◽  
Missense Mutations ◽  
Xylose Consumption ◽  
E Coli ◽  
Fermentation Technology ◽  
Xylose Transporter

Abstract Background Microorganisms can prioritize the uptake of different sugars depending on their metabolic needs and preferences. When both D-glucose and D-xylose are present in growth media, E. coli cells typically consume D-glucose first and then D-xylose. Similarly, when E. coli BL21(DE3) is provided with both D-glucose and D-xylose under anaerobic conditions, glucose is consumed first, whereas D-xylose is consumed very slowly. Results When BL21(DE3) was adaptively evolved via subculture, the consumption rate of D-xylose increased gradually. Strains JH001 and JH019, whose D-xylose consumption rate was faster, were isolated after subculture. Genome analysis of the JH001 and JH019 strains revealed that C91A (Q31K) and C740T (A247V) missense mutations in the xylR gene (which encodes the XylR transcriptional activator), respectively, controlled the expression of the xyl operon. RT-qPCR analyses demonstrated that the XylR mutation caused a 10.9-fold and 3.5-fold increase in the expression of the xylA (xylose isomerase) and xylF (xylose transporter) genes, respectively, in the adaptively evolved JH001 and JH019 strains. A C91A adaptive mutation was introduced into a new BL21(DE3) background via single-base genome editing, resulting in immediate and efficient D-xylose consumption. Conclusions Anaerobically-adapted BL21(DE3) cells were obtained through short-term adaptive evolution and xylR mutations responsible for faster D-xylose consumption were identified, which may aid in the improvement of microbial fermentation technology.

scholarly journals Exploring the Potential of Corynebacterium glutamicum to Produce the Compatible Solute Mannosylglycerate

2021 ◽  
Vol 9 ◽  
Author(s):  
Andreas Schwentner ◽  
Heiko Neugebauer ◽  
Serin Weinmann ◽  
Helena Santos ◽  
Bernhard J. Eikmanns
Keyword(s):  
Carbon Source ◽  
Corynebacterium Glutamicum ◽  
Freeze Drying ◽  
Cold Water ◽  
Dry Weight ◽  
Compatible Solute ◽  
Protein Stabilization ◽  
Gene Encoding ◽  
Dehalococcoides Mccartyi ◽  
Growth Production

The compatible solute mannosylglycerate (MG) has exceptional properties in terms of protein stabilization and protection under salt, heat, and freeze-drying stresses as well as against protein aggregation. Due to these characteristics, MG possesses large potential for clinical and biotechnological applications. To achieve efficient MG production, Corynebacterium glutamicum was equipped with a bifunctional MG synthase (encoded by mgsD and catalyzing the condensation of 3-phosphoglycerate and GDP-mannose to MG) from Dehalococcoides mccartyi. The resulting strain C. glutamicum (pEKEx3 mgsD) intracellularly accumulated about 111 mM MG (60 ± 9 mg gCDW−1) with 2% glucose as a carbon source. To enable efficient mannose metabolization, the native manA gene, encoding mannose 6-phosphate isomerase, was overexpressed. Combined overexpression of manA and mgsD from two plasmids in C. glutamicum resulted in intracellular MG accumulation of up to ca. 329 mM [corresponding to 177 mg g cell dry weight (CDW)−1] with glucose, 314 mM (168 mg gCDW−1) with glucose plus mannose, and 328 mM (176 mg gCDW−1) with mannose as carbon source(s), respectively. The product was successfully extracted from cells by using a cold water shock, resulting in up to 5.5 mM MG (1.48 g L−1) in supernatants. The two-plasmid system was improved by integrating the mgsD gene into the manA-bearing plasmid and the resulting strain showed comparable production but faster growth. Repeated cycles of growth/production and extraction of MG in a bacterial milking-like experiment showed that cells could be recycled, which led to a cumulative MG production of 19.9 mM (5.34 g L−1). The results show that the newly constructed C. glutamicum strain produces MG from glucose and mannose and that a cold water shock enables extraction of MG from the cytosol into the medium.

scholarly journals Molecular Cloning and Functional Expression inLactobacillus plantarum 80 of xylT, Encoding thed-Xylose–H+ Symporter ofLactobacillus brevis

1998 ◽  
Vol 64 (12) ◽  
pp. 4720-4728 ◽  
Author(s):  
Stéphane Chaillou ◽  
Yeou-Cherng Bor ◽  
Carl A. Batt ◽  
Pieter W. Postma ◽  
Peter H. Pouwels
Keyword(s):  
Xylose Isomerase ◽  
Proton Motive Force ◽  
Motive Force ◽  
Affinity Constant ◽  
Transport Activity ◽  
Gene Encoding ◽  
Kinase Gene ◽  
E Coli ◽  
Xylose Transport ◽  
Xylulose Kinase

ABSTRACT A 3-kb region, located downstream of the Lactobacillus brevis xylA gene (encoding d-xylose isomerase), was cloned in Escherichia coli TG1. The sequence revealed two open reading frames which could code for the d-xylulose kinase gene (xylB) and another gene (xylT) encoding a protein of 457 amino acids with significant similarity to thed-xylose–H+ symporters of E. coli, XylE (57%), and Bacillus megaterium, XylT (58%), to the d-xylose–Na+ symporter ofTetragenococcus halophila, XylE (57%), and to thel-arabinose–H+ symporter of E. coli, AraE (60%). The L. brevis xylABT genes showed an arrangement similar to that of the B. megaterium xylABT operon and the T. halophila xylABE operon. Southern hybridization performed with the Lactobacillus pentosus xylR gene (encoding the d-xylose repressor protein) as a probe revealed the existence of a xylR homologue inL. brevis which is not located with thexyABT locus. The existence of a functional XylR was further suggested by the presence of xylO sequences upstream ofxylA and xylT and by the requirement ofd-xylose for the induction of d-xylose isomerase, d-xylulose kinase, and d-xylose transport activities in L. brevis. When L. brevis was cultivated in a mixture of d-glucose andd-xylose, the d-xylose isomerase andd-xylulose kinase activities were reduced fourfold and thed-xylose transport activity was reduced by sixfold, suggesting catabolite repression by d-glucose ofd-xylose assimilation. The xylT gene was functionally expressed in Lactobacillus plantarum 80, a strain which lacks proton motive force-linked d-xylose transport activity. The role of the XylT protein was confirmed by the accumulation of d-xylose in L. plantarum80 cells, and this accumulation was dependent on the proton motive force generated by either malolactic fermentation or by the metabolism of d-glucose. The apparent affinity constant of XylT ford-xylose was approximately 215 μM, and the maximal initial velocity of transport was 35 nmol/min per mg (dry weight). Furthermore, of a number of sugars tested, only 6-deoxy-d-glucose inhibited the transport ofd-xylose by XylT competitively, with aKi of 220 μM.

scholarly journals A novel d-xylose isomerase from the gut of the wood feeding beetle Odontotaenius disjunctus efficiently expressed in Saccharomyces cerevisiae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paulo César Silva ◽  
Javier A. Ceja-Navarro ◽  
Flávio Azevedo ◽  
Ulas Karaoz ◽  
Eoin L. Brodie ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Specific Activity ◽  
Xylose Isomerase ◽  
Maximal Activity ◽  
Primary Sources ◽  
Xylose Consumption ◽  
Renewable Fuel ◽  
Bulk Chemicals ◽  
Pentose Sugar ◽  
New Gene

AbstractCarbohydrate rich substrates such as lignocellulosic hydrolysates remain one of the primary sources of potentially renewable fuel and bulk chemicals. The pentose sugar d-xylose is often present in significant amounts along with hexoses. Saccharomyces cerevisiae can acquire the ability to metabolize d-xylose through expression of heterologous d-xylose isomerase (XI). This enzyme is notoriously difficult to express in S. cerevisiae and only fourteen XIs have been reported to be active so far. We cloned a new d-xylose isomerase derived from microorganisms in the gut of the wood-feeding beetle Odontotaenius disjunctus. Although somewhat homologous to the XI from Piromyces sp. E2, the new gene was identified as bacterial in origin and the host as a Parabacteroides sp. Expression of the new XI in S. cerevisiae resulted in faster aerobic growth than the XI from Piromyces on d-xylose media. The d-xylose isomerization rate conferred by the new XI was also 72% higher, while absolute xylitol production was identical in both strains. Interestingly, increasing concentrations of xylitol (up to 8 g L−1) appeared not to inhibit d-xylose consumption. The newly described XI displayed 2.6 times higher specific activity, 37% lower KM for d-xylose, and exhibited higher activity over a broader temperature range, retaining 51% of maximal activity at 30 °C compared with only 29% activity for the Piromyces XI.

scholarly journals Efficient Anaerobic Consumption of D-xylose by E. coli BL21(DE3) via xylR Adaptive Mutation

2021 ◽  
Author(s):  
Jung Min Heo ◽  
Hyun Ju Kim ◽  
Sang Jun Lee
Keyword(s):  
Consumption Rate ◽  
Xylose Isomerase ◽  
Fold Increase ◽  
Adaptive Mutation ◽  
Growth Media ◽  
Missense Mutations ◽  
Xylose Consumption ◽  
E Coli ◽  
Fermentation Technology ◽  
Xylose Transporter

Abstract Background: Microorganisms can prioritize the uptake of different sugars depending on their metabolic needs and preferences. When both D-glucose and D-xylose are present in growth media, E. coli cells typically consume D-glucose first and then D-xylose. Similarly, when E. coli BL21(DE3) is provided with both glucose and xylose under anaerobic conditions, glucose is consumed first, whereas xylose is consumed very slowly.Results: When BL21(DE3) was adaptively evolved via subculture, the consumption rate of D-xylose increased gradually. Strains JH001 and JH019, whose D-xylose consumption rate was faster, were isolated after subculture. Genome analysis of the JH001 and JH019 strains revealed that C91A (Q31K) and C740T (A247V) missense mutations in the xylR gene (which encodes the XylR transcriptional activator), respectively, controlled the expression of the xyl operon. RT-qPCR analyses demonstrated that the XylR mutation caused a 10.9-fold and 3.5-fold increase in the expression of the xylA (xylose isomerase) and xylF (xylose transporter) genes, respectively, in the adaptively evolved JH001 and JH019 strains. A C91A adaptive mutation was introduced into a new BL21(DE3) background via single-base genome editing, resulting in immediate and efficient D-xylose consumption. Conclusions: We obtained anaerobically-adapted BL21(DE3) cells through short-term adaptive evolution and identified xylR mutations responsible for faster xylose consumption, which may facilitate the improvement of microbial fermentation technology.

scholarly journals Development and Application of an Arabinose-Inducible Expression System by Facilitating Inducer Uptake in Corynebacterium glutamicum

2012 ◽  
Vol 78 (16) ◽  
pp. 5831-5838 ◽  
Author(s):  
Yun Zhang ◽  
Xiuling Shang ◽  
Shujuan Lai ◽  
Guoqiang Zhang ◽  
Yong Liang ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Fluorescent Protein ◽  
Expression System ◽  
Carbon Sources ◽  
Inducible Expression ◽  
Gene Encoding ◽  
Content Type ◽  
E Coli ◽  
Inducible Expression System ◽  
Green Fluorescent

ABSTRACTCorynebacterium glutamicumis currently used for the industrial production of a variety of biological materials. Many available inducible expression systems in this species uselac-derived promoters fromEscherichia colithat exhibit much lower levels of inducible expression and leaky basal expression. We developed an arabinose-inducible expression system that contains thel-arabinose regulator AraC, thePBADpromoter from thearaBADoperon, and thel-arabinose transporter AraE, all of which are derived fromE. coli. The level of induciblePBAD-based expression could be modulated over a wide concentration range from 0.001 to 0.4%l-arabinose. This system tightly controlled the expression of the uracil phosphoribosyltransferase without leaky expression. When the gene encoding green fluorescent protein (GFP) was under the control ofPBADpromoter, flow cytometry analysis showed that GFP was expressed in a highly homogeneous profile throughout the cell population. In contrast to the case inE. coli,PBADinduction was not significantly affected in the presence of different carbon sources inC. glutamicum, which makes it useful in fermentation applications. We used this system to regulate the expression of theodhIgene fromC. glutamicum, which encodes an inhibitor of α-oxoglutarate dehydrogenase, resulting in high levels of glutamate production (up to 13.7 mM) under biotin nonlimiting conditions. This system provides an efficient tool available for molecular biology and metabolic engineering ofC. glutamicum.

scholarly journals Dynamic Co-Cultivation Process of Corynebacterium glutamicum Strains for the Fermentative Production of Riboflavin

Fermentation ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 11
Author(s):  
Fernando Pérez-García ◽  
Arthur Burgardt ◽  
Dina R. Kallman ◽  
Volker F. Wendisch ◽  
Nadav Bar
Keyword(s):  
Corynebacterium Glutamicum ◽  
Xanthomonas Campestris ◽  
Product Formation ◽  
Volumetric Productivity ◽  
Riboflavin Production ◽  
Xylose Consumption ◽  
Single Strain ◽  
Sugar Mixtures ◽  
Fed Batch Fermentation ◽  
Overexpressing Strain

Residual streams from lignocellulosic processes contain sugar mixtures of glucose, xylose, and mannose. Here, the industrial workhorse Corynebacterium glutamicum was explored as a research platform for the rational utilization of a multiple sugar substrate. The endogenous manA gene was overexpressed to enhance mannose utilization. The overexpression of the xylA gene from Xanthomonas campestris in combination with the endogenous xylB gene enabled xylose consumption by C. glutamicum. Furthermore, riboflavin production was triggered by overexpressing the sigH gene from C. glutamicum. The resulting strains were studied during batch fermentations in flasks and 2 L lab-scale bioreactors separately using glucose, mannose, xylose, and a mixture of these three sugars as a carbon source. The production of riboflavin and consumption of sugars were improved during fed-batch fermentation thanks to a dynamic inoculation strategy of manA overexpressing strain and xylAB overexpressing strain. The final riboflavin titer, yield, and volumetric productivity from the sugar mixture were 27 mg L−1, 0.52 mg g−1, and 0.25 mg L−1 h−1, respectively. It reached a 56% higher volumetric productivity with 45% less by-product formation compared with an equivalent process inoculated with a single strain overexpressing the genes xylAB and manA combined. The results indicate the advantages of dynamic multi strains processes for the conversion of sugar mixtures.

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