scholarly journals Engineering redox-balanced ethanol production in the cellulolytic and extremely thermophilic bacterium, Caldicellulosiruptor bescii

2018 ◽  
Vol 7 ◽  
pp. e00073 ◽  
Author(s):  
Amanda M. Williams-Rhaesa ◽  
Gabriel M. Rubinstein ◽  
Israel M. Scott ◽  
Gina L. Lipscomb ◽  
Farris L. Poole, II ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Thermophilic Bacterium ◽  
Caldicellulosiruptor Bescii

scholarly journals Molecular and Biochemical Analyses of the GH44 Module of CbMan5B/Cel44A, a Bifunctional Enzyme from the Hyperthermophilic Bacterium Caldicellulosiruptor bescii

2012 ◽  
Vol 78 (19) ◽  
pp. 7048-7059 ◽  
Author(s):  
Libin Ye ◽  
Xiaoyun Su ◽  
George E. Schmitz ◽  
Young Hwan Moon ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Specific Activity ◽  
Cellulose Hydrolysis ◽  
Thermophilic Bacterium ◽  
Carbohydrate Binding ◽  
Content Type ◽  
Caldicellulosiruptor Bescii ◽  
C Terminus ◽  
Carbohydrate Binding Modules ◽  
Β Sheets ◽  
Biochemical Analyses

ABSTRACTA large polypeptide encoded in the genome of the thermophilic bacteriumCaldicellulosiruptor besciiwas determined to consist of two glycoside hydrolase (GH) modules separated by two carbohydrate-binding modules (CBMs). Based on the detection of mannanase and endoglucanase activities in the N-terminal GH5 and the C-terminal GH44 module, respectively, the protein was designated CbMan5B/Cel44A. A GH5 module with >99% identity from the same organism was characterized previously (X. Su, R. I. Mackie, and I. K. Cann, Appl. Environ. Microbiol.78:2230-2240, 2012); therefore, attention was focused on CbMan5A/Cel44A-TM2 (or TM2), which harbors the GH44 module and the two CBMs. On cellulosic substrates, TM2 had an optimal temperature and pH of 85°C and 5.0, respectively. Although the amino acid sequence of the GH44 module of TM2 was similar to those of other GH44 modules that hydrolyzed cello-oligosaccharides, cellulose, lichenan, and xyloglucan, it was unique that TM2 also displayed modest activity on mannose-configured substrates and xylan. The TM2 protein also degraded Avicel with higher specific activity than activities reported for its homologs. The GH44 catalytic module is composed of a TIM-like domain and a β-sandwich domain, which consists of one β-sheet at the N terminus and nine β-sheets at the C terminus. Deletion of one or more β-sheets from the β-sandwich domain resulted in insoluble proteins, suggesting that the β-sandwich domain is essential for proper folding of the polypeptide. Combining TM2 with three other endoglucanases fromC. besciiled to modest synergistic activities during degradation of cellulose, and based on our results, we propose a model for cellulose hydrolysis and utilization byC. bescii.

scholarly journals The N-Terminal GH10 Domain of a Multimodular Protein from Caldicellulosiruptor bescii Is a Versatile Xylanase/β-Glucanase That Can Degrade Crystalline Cellulose

2015 ◽  
Vol 81 (11) ◽  
pp. 3823-3833 ◽  
Author(s):  
Xianli Xue ◽  
Rong Wang ◽  
Tao Tu ◽  
Pengjun Shi ◽  
Rui Ma ◽  
...  
Keyword(s):  
Thermophilic Bacterium ◽  
Crystalline Cellulose ◽  
Content Type ◽  
Multiple Substrates ◽  
Caldicellulosiruptor Bescii ◽  
Truncation Mutant ◽  
Interesting Candidate ◽  
High Sequence Homology ◽  
Novel Strategy ◽  
Cellulose Binding

ABSTRACTThe genome of the thermophilic bacteriumCaldicellulosiruptor besciiencodes three multimodular enzymes with identical C-terminal domain organizations containing two consecutive CBM3b modules and one glycoside hydrolase (GH) family 48 (GH48) catalytic module. However, the three proteins differ much in their N termini. Among these proteins, CelA (orC. besciiCel9A [CbCel9A]/Cel48A) with a GH9/CBM3c binary partner in the N terminus has been shown to use a novel strategy to degrade crystalline cellulose, which leads to its outstanding cellulose-cleaving activity. Here we show thatC. besciiXyn10C (CbXyn10C), the N-terminal GH10 domain from CbXyn10C/Cel48B, can also degrade crystalline cellulose, in addition to heterogeneous xylans and barley β-glucan. The data from substrate competition assays, mutational studies, molecular modeling, and docking point analyses point to the existence of only one catalytic center in the bifunctional xylanase/β-glucanase. The specific activities of the recombinant CbXyn10C on Avicel and filter paper were comparable to those of GH9/CBM3c of the robust CelA expressed inEscherichia coli. Appending one or two cellulose-binding CBM3bs enhanced the activities of CbXyn10C in degrading crystalline celluloses, which were again comparable to those of the GH9/CBM3c-CBM3b-CBM3b truncation mutant of CelA. Since CbXyn10C/Cel48B and CelA have similar domain organizations and high sequence homology, the endocellulase activity observed in CbXyn10C leads us to speculate that CbXyn10C/Cel48B may use the same strategy that CelA uses to hydrolyze crystalline cellulose, thus helping the excellent crystalline cellulose degraderC. besciiacquire energy from the environment. In addition, we also demonstrate that CbXyn10C may be an interesting candidate enzyme for biotechnology due to its versatility in hydrolyzing multiple substrates with different glycosidic linkages.

scholarly journals Insights into plant biomass conversion from the genome of the anaerobic thermophilic bacterium Caldicellulosiruptor bescii DSM 6725

2011 ◽  
Vol 39 (8) ◽  
pp. 3240-3254 ◽  
Author(s):  
Phuongan Dam ◽  
Irina Kataeva ◽  
Sung-Jae Yang ◽  
Fengfeng Zhou ◽  
Yanbin Yin ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Biomass Conversion ◽  
Thermophilic Bacterium ◽  
Caldicellulosiruptor Bescii

Native xylose-inducible promoter expands the genetic tools for the biomass-degrading, extremely thermophilic bacterium Caldicellulosiruptor bescii

Extremophiles ◽  
2018 ◽  
Vol 22 (4) ◽  
pp. 629-638 ◽  
Author(s):  
Amanda M. Williams-Rhaesa ◽  
Nanaakua K. Awuku ◽  
Gina L. Lipscomb ◽  
Farris L. Poole ◽  
Gabriel M. Rubinstein ◽  
...  
Keyword(s):  
Inducible Promoter ◽  
Thermophilic Bacterium ◽  
Genetic Tools ◽  
Caldicellulosiruptor Bescii

scholarly journals Two pectate lyases from Caldicellulosiruptor bescii with the same CALG domain had distinct properties on plant biomass degradation

2020 ◽  
Author(s):  
Hamed I. Hamouda ◽  
Nasir Ali ◽  
Hang Su ◽  
Jie Feng ◽  
Ming Lu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plant Biomass ◽  
Degradation Products ◽  
Amino Acid Identity ◽  
Thermophilic Bacterium ◽  
Carbohydrate Binding ◽  
Carbohydrate Binding Module ◽  
Acid Identity ◽  
Pectate Lyases ◽  
Caldicellulosiruptor Bescii

AbstractPectin deconstruction is the initial step in breaking the recalcitrance of plant biomass by using selected microorganisms that carry pectinolytic enzymes. Pectate lyases that cleave α-1,4-galacturonosidic linkage of pectin are widely used in industries, such as paper making and fruit softening. However, reports on pectate lyases with high thermostability are few. Two pectate lyases (CbPL3 and CbPL9) from a thermophilic bacterium Caldicellulosiruptor bescii were investigated. Although these two enzymes belonged to different families of polysaccharide lyase, both were Ca2+-dependent. Similar biochemical properties were shown under optimized conditions 80 °C–85 °C and pH 8–9. However, the degradation products on pectin and polygalacturonic acids (pGA) were different, revealing the distinct mode of action. A concanavalin A-like lectin/glucanase (CALG) domain, located in the N-terminus of two CbPLs, shares 100% amino acid identity. CALG-truncated mutant of CbPL9 showed lower activities than the wild-type, whereas the CbPL3 with CALG knock-out portion was reported with enhanced activities, thereby revealing the different roles of CALG in two CbPLs. I-TASSER predicted that the CALG in two CbPLs is structurally close to the family 66 carbohydrate binding module (CBM66). Furthermore, substrate-binding assay indicated that the catalytic domains in two CbPLs had strong affinities on pectate-related substrates, but CALG showed weak interaction with a number of lignocellulosic carbohydrates, except sodium carboxymethyl cellulose and sodium alginate. Finally, scanning electron microscope analysis and total reducing sugar assay showed that the two enzymes could improve the saccharification of switchgrass. The two CbPLs are impressive sources for degradation of plant biomass.ImportanceThermophilic proteins could be implemented in diverse industrial applications. We sought to characterize two pectate lyases, CbPL3 and CbPL9, from a thermophilic bacterium Caldicellulosiruptor bescii. The two enzymes had high optimum temperature, low optimum pH, and good thermostability at evaluated temperature. A family-66 carbohydrate binding module (CBM66) was identified in two CbPLs with sharing 100% amino acid identity. Deletion of CBM66 obviously decreased the activity of CbPL9, but increase the activity and thermostability of CbPL3, suggesting the different roles of CBM66 in two enzymes. Moreover, the degradation products by two CbPLs were different. These results revealed these enzymes could represent a potential pectate lyase for applications in paper and textile industries.

scholarly journals Cellulosic ethanol production via consolidated bioprocessing at 75 °C by engineered Caldicellulosiruptor bescii

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Daehwan Chung ◽  
Minseok Cha ◽  
Elise N. Snyder ◽  
James G. Elkins ◽  
Adam M. Guss ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Cellulosic Ethanol ◽  
Consolidated Bioprocessing ◽  
Caldicellulosiruptor Bescii

Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium

2011 ◽  
Vol 64 (2) ◽  
pp. 341-347 ◽  
Author(s):  
Ana F. Tomas ◽  
Dimitar Karakashev ◽  
Irini Angelidaki
Keyword(s):  
Production Process ◽  
Ethanol Production ◽  
Yeast Extract ◽  
Ethanol Yield ◽  
Thermophilic Bacterium ◽  
Promising Candidate ◽  
Theoretical Yield ◽  
Ethanol Yields ◽  
Nutrients Concentration ◽  
Xylose Concentration

An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixed culture, originally isolated from a hydrogen producing reactor operated at 70 °C. Ethanol yields were assessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to grow without nutrient addition (yeast extract, peptone and vitamins) was also assessed. The maximum ethanol yield achieved was 1.28 molethanol/molxylose consumed (77% of the theoretical yield), at 2 g/l of initial xylose concentration. The isolate was able to grow and produce ethanol as the main fermentation product under most of the conditions tested, including in media lacking vitamins, peptone and yeast extract. The results indicate that this new organism is a promising candidate for the development of a second generation bio-ethanol production process.

Sign in / Sign up

Export Citation Format

Share Document