51
|
Abstract
Cellulose is an abundant and renewable biopolymer that can be used for biofuel generation; however, structural entrapment with other cell wall components hinders enzyme-substrate interactions, a key bottleneck for ethanol production. Biomass is routinely subjected to treatments that facilitate cellulase-cellulose contacts. Cellulases and glucosidases act by hydrolyzing glycosidic bonds of linear glucose β-1,4-linked polymers, producing glucose. Here we describe eight high-temperature-operating cellulases (TCel enzymes) identified from a survey of thermobacterial and archaeal genomes. Three TCel enzymes preferentially hydrolyzed soluble cellulose, while two preferred insoluble cellulose such as cotton linters and filter paper. TCel enzymes had temperature optima ranging from 85°C to 102°C. TCel enzymes were stable, retaining 80% of initial activity after 120 h at 85°C. Two modes of cellulose breakdown, i.e., with endo- and exo-acting glucanases, were detected, and with two-enzyme combinations at 85°C, synergistic cellulase activity was observed for some enzyme combinations.
Collapse
|
52
|
Cloning, expression and characterization of an acidic endo-polygalacturonase from Bispora sp. MEY-1 and its potential application in juice clarification. Process Biochem 2011. [DOI: 10.1016/j.procbio.2010.08.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
53
|
Teng Y, Yin Q, ding M, Zhao F. Purification and characterization of a novel endo-β-1,4-glucanases , AfEG22, from the giant snail, Achatina fulica frussac. Acta Biochim Biophys Sin (Shanghai) 2010; 42:729-34. [PMID: 20870931 DOI: 10.1093/abbs/gmq083] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, we confirmed that at least three endo-β-1,4-glucanases existed in the digestive juice of the giant snail, Achatina fulica ferussac, by Congo red staining assay. One of these enzymes, a novel endo-β-1,4-glucanase (AfEG22), was purified 29.5-fold by gel filtration, anion exchange, and hydrophobic interaction chromatography. The carboxymethyl cellulose (CMC) hydrolytic activity of the purified enzyme was 12.3 U/mg protein. The molecular mass of AfEG22 was 22081 Da determined by MALDI-TOF. N-terminal amino acid sequencing revealed a sequence of EQRCTNQGGILKYYNT, which did not have significant homology with any proteins in BLAST database. The optimal pH and temperature for hydrolytic activity toward CMC were pH 4.0 and 50°C, respectively. AfEG22 was stable between pH 3.0 and pH 12.0 when incubated at 4°C for 3 h or at 37°C for 1 h. The enzyme remained more than 80% activity between pH 4.5 and pH 7.0 after incubation at 50°C for 1 h. AfEG22 possessed excellent thermostability as more than 70% activity was remained after incubation at 60°C for 3 h. Substrate specific analysis revealed that AfEG22 was a typical endo-β-1,4-glucanase. This is the first time to report a novel endo-β-1,4-glucanase with high stability from the digestive juice of A. fulica.
Collapse
Affiliation(s)
- Yigang Teng
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China
| | | | | | | |
Collapse
|
54
|
Miller PS, Blum PH. Extremophile-inspired strategies for enzymatic biomass saccharification. ENVIRONMENTAL TECHNOLOGY 2010; 31:1005-1015. [PMID: 20662388 DOI: 10.1080/09593330903536113] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Domestic ethanol production in the USA relies on starch feedstocks using a first generation bioprocess. Enzymes that contribute to this industry remain of critical value in new and established markets as commodity additives and for in planta production. A transition to non-food feedstocks is both desirable and essential to enable larger scale production. This objective would relieve dependence on foreign oil and strengthen the national economy. Feedstocks derived from corn stover, wheat straw, perennial grasses and timber require pretreatment to increase the accessibility of the cellulosic and hemicellulosic substrates to commodity enzymes for saccharification, which is followed by fermentation-based conversion of monosaccharides to ethanol. Hot acid pretreatment is the industrial standard method used to achieve deconstruction of lignocellulosic biomass. Therefore, enzymes that tolerate both acid and heat may contribute toward the improvement of lignocellulosic biomass processing. These enzymes are produced naturally by extremely thermophilic microbes, sometimes called extremophiles. This review summarizes information on enzymes from selected (acido)thermophiles that mediate saccharification of alpha- and beta-linked carbohydrates of relevance to biomass processing.
Collapse
Affiliation(s)
- P S Miller
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | |
Collapse
|
55
|
Cobucci-Ponzano B, Aurilia V, Riccio G, Henrissat B, Coutinho PM, Strazzulli A, Padula A, Corsaro MM, Pieretti G, Pocsfalvi G, Fiume I, Cannio R, Rossi M, Moracci M. A new archaeal beta-glycosidase from Sulfolobus solfataricus: seeding a novel retaining beta-glycan-specific glycoside hydrolase family along with the human non-lysosomal glucosylceramidase GBA2. J Biol Chem 2010; 285:20691-703. [PMID: 20427274 DOI: 10.1074/jbc.m109.086470] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carbohydrate active enzymes (CAZymes) are a large class of enzymes, which build and breakdown the complex carbohydrates of the cell. On the basis of their amino acid sequences they are classified in families and clans that show conserved catalytic mechanism, structure, and active site residues, but may vary in substrate specificity. We report here the identification and the detailed molecular characterization of a novel glycoside hydrolase encoded from the gene sso1353 of the hyperthermophilic archaeon Sulfolobus solfataricus. This enzyme hydrolyzes aryl beta-gluco- and beta-xylosides and the observation of transxylosylation reactions products demonstrates that SSO1353 operates via a retaining reaction mechanism. The catalytic nucleophile (Glu-335) was identified through trapping of the 2-deoxy-2-fluoroglucosyl enzyme intermediate and subsequent peptide mapping, while the general acid/base was identified as Asp-462 through detailed mechanistic analysis of a mutant at that position, including azide rescue experiments. SSO1353 has detectable homologs of unknown specificity among Archaea, Bacteria, and Eukarya and shows distant similarity to the non-lysosomal bile acid beta-glucosidase GBA2 also known as glucocerebrosidase. On the basis of our findings we propose that SSO1353 and its homologs are classified in a new CAZy family, named GH116, which so far includes beta-glucosidases (EC 3.2.1.21), beta-xylosidases (EC 3.2.1.37), and glucocerebrosidases (EC 3.2.1.45) as known enzyme activities.
Collapse
|
56
|
Zhao J, Shi P, Luo H, Yang P, Zhao H, Bai Y, Huang H, Wang H, Yao B. An acidophilic and acid-stable beta-mannanase from phialophora sp. p13 with high mannan hydrolysis activity under simulated gastric conditions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:3184-3190. [PMID: 20143777 DOI: 10.1021/jf904367r] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A beta-mannanase gene, man5AP13, was cloned from Phialophora sp. P13 and expressed in Pichia pastoris. The deduced amino acid sequence of the mature enzyme, MAN5AP13, had highest identity (53%) with the glycoside hydrolase family 5 beta-mannanase from Bispora sp. MEY-1. The purified recombinant beta-mannanase was acidophilic and acid stable, exhibiting maximal activity at pH 1.5 and retaining >60% of the initial activity over the pH range 1.5-7.0. The optimum temperature was 60 degrees C. The specific activity, K(m) and V(max) for locust bean gum substrate were 851 U/mg, 2.5 mg/mL, and 1667.7 U/min.mg, respectively. The enzyme had excellent activity and stability under simulated gastric conditions, and the released reducing sugar of locust bean gum was significantly enhanced by one-fold in simulated gastric fluid containing pepsin in contrast to that without pepsin. All these properties make MAN5AP13 a potential additive for use in the food and feed industries.
Collapse
Affiliation(s)
- Junqi Zhao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
| | | | | | | | | | | | | | | | | |
Collapse
|
57
|
Yeoman CJ, Han Y, Dodd D, Schroeder CM, Mackie RI, Cann IKO. Thermostable enzymes as biocatalysts in the biofuel industry. ADVANCES IN APPLIED MICROBIOLOGY 2010; 70:1-55. [PMID: 20359453 DOI: 10.1016/s0065-2164(10)70001-0] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Lignocellulose is the most abundant carbohydrate source in nature and represents an ideal renewable energy source. Thermostable enzymes that hydrolyze lignocellulose to its component sugars have significant advantages for improving the conversion rate of biomass over their mesophilic counterparts. We review here the recent literature on the development and use of thermostable enzymes for the depolymerization of lignocellulosic feedstocks for biofuel production. Furthermore, we discuss the protein structure, mechanisms of thermostability, and specific strategies that can be used to improve the thermal stability of lignocellulosic biocatalysts.
Collapse
Affiliation(s)
- Carl J Yeoman
- Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
| | | | | | | | | | | |
Collapse
|
58
|
Rastegari AA, Bordbar AK, Taheri-Kafrani A. Interaction of cellulase with cationic surfactants: Using surfactant membrane selective electrodes and fluorescence spectroscopy. Colloids Surf B Biointerfaces 2009; 73:132-9. [DOI: 10.1016/j.colsurfb.2009.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 05/07/2009] [Accepted: 05/12/2009] [Indexed: 11/17/2022]
|
59
|
Belien T, Joye IJ, Delcour JA, Courtin CM. Computational design-based molecular engineering of the glycosyl hydrolase family 11 B. subtilis XynA endoxylanase improves its acid stability. Protein Eng Des Sel 2009; 22:587-96. [DOI: 10.1093/protein/gzp024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
60
|
A novel highly acidic β-mannanase from the acidophilic fungus Bispora sp. MEY-1: gene cloning and overexpression in Pichia pastoris. Appl Microbiol Biotechnol 2009; 82:453-61. [DOI: 10.1007/s00253-008-1766-x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 10/22/2008] [Accepted: 10/22/2008] [Indexed: 11/25/2022]
|
61
|
Zheng B, Yang W, Wang Y, Feng Y, Lou Z. Crystallization and preliminary crystallographic analysis of thermophilic cellulase from Fervidobacterium nodosum Rt17-B1. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:219-22. [PMID: 19255469 DOI: 10.1107/s1744309109001316] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 01/12/2009] [Indexed: 11/10/2022]
Abstract
FnCel5A, a thermostable endoglucanase, is a member of glycohydrolase family 5 which catalyzes the hydrolysis of cellulose to glucose in the thermophilic bacterium Fervidobacterium nodosum Rt17-B1. FnCel5A is particularly interesting because of its high thermostability (T(opt) = 353 K, half-life 48 h) and its high specific activity towards carboxymethylcellulose. These properties make FnCel5A an attractive target for protein engineering to improve cellulase activity. In order to resolve the crystal structure of FnCel5A and to gain a better understanding of its biological function, recombinant FnCel5A was expressed, purified and crystallized at 291 K using NaH(2)PO(4)/KH(2)PO(4) as a precipitant. A 2.4 A resolution native data set was collected from a single flash-cooled crystal (100 K) using 20%(v/v) glycerol as a cryoprotectant. These crystals belonged to space group P2(1)2(1)2, with unit-cell parameters a = 53.5, b = 81.7, c = 85.2 A, alpha = beta = gamma = 90 degrees . One molecule is assumed to be present per asymmetric unit, which gives a Matthews coefficient of 2.5 A(3) Da(-1). A data set was also collected to 1.7 A resolution from a selenomethionyl derivative; it belonged to space group P2(1)2(1)2(1) with the same unit-cell parameters as the native crystals.
Collapse
Affiliation(s)
- Baisong Zheng
- Tsinghua University, Beijing, People's Republic of China
| | | | | | | | | |
Collapse
|
62
|
Evidence that the xylanase activity from Sulfolobus solfataricus Oα is encoded by the endoglucanase precursor gene (sso1354) and characterization of the associated cellulase activity. Extremophiles 2008; 12:689-700. [DOI: 10.1007/s00792-008-0175-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 05/26/2008] [Indexed: 10/22/2022]
|
63
|
Gao J, Weng H, Xi Y, Zhu D, Han S. Purification and characterization of a novel endo-beta-1,4-glucanase from the thermoacidophilic Aspergillus terreus. Biotechnol Lett 2007; 30:323-7. [PMID: 17928959 DOI: 10.1007/s10529-007-9536-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 09/04/2007] [Accepted: 09/04/2007] [Indexed: 11/29/2022]
Abstract
An endo-beta-1,4-glucanase from a thermoacidophilic fungus, Aspergillus terreus M11, was purified 18-fold with 14% yield and a specific activity of 67 U mg(-1) protein. The optimal pH was 2 and the cellulase was stable from pH 2 to 5. The cellulase had a temperature optimum of 60 degrees C measured over 30 min and retained more than 60% of its activity after heating at 70 degrees C for 1 h. The molecular mass of the cellulase was about 25 kDa. Its activity was inhibited by 77% by Hg(2+) (2 mM) and by 59% by Cu(2+) (2 mM).
Collapse
Affiliation(s)
- Jianmin Gao
- Department of Bioengineering, Zhengzhou University, 100 Kexue Road, Zhengzhou 450001, PR China
| | | | | | | | | |
Collapse
|
64
|
Bryant P, Kriek M, Wood RJ, Roach PL. The activity of a thermostable lipoyl synthase from Sulfolobus solfataricus with a synthetic octanoyl substrate. Anal Biochem 2006; 351:44-9. [PMID: 16500612 DOI: 10.1016/j.ab.2006.01.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 12/06/2005] [Accepted: 01/11/2006] [Indexed: 11/25/2022]
Abstract
The protein lipoyl synthase (LipA) is essential for lipoic acid biosynthesis via sulfur insertions into a protein-bound octanoyl group. We have developed an in vitro assay for LipA using a synthetic tetrapeptide substrate, containing an N(epsilon)-octanoyl lysine residue, corresponding in sequence to the lipoyl binding domain of the E2 subunit of pyruvate dehydrogenase. A putative LipA from the hypothermophilic archaea Sulfolobus solfataricus was expressed in Escherichia coli and purified, and the activity was measured using this novel assay. The optimal temperature for the S. solfataricus LipA-dependent formation of the lipoyl group was found to be 60 degrees C.
Collapse
Affiliation(s)
- Penny Bryant
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | | | | | | |
Collapse
|