Xylanase genes, cloning

The literature contains numerous examples of cloning xylanase genes with bacterial gene donors and acceptors (Table II). In most cases strains of Escherichia... 

Special attention has been paid by sevo groups to cloning xylanase genes from thermophilic microorganisms as a source of thermostable xylanases. Cloning of such genes in mesophilic recepients offers a convenient way to purify xylanases simply by a heat denaturation of the more heat-labile proteins of the host (54). Applications are limited to those enzymes that possess thermostability considerably higher than the majority of the host cell proteins. 

Similar approaches to cloning of bacterial xylanases have been used for genes from Clostridium acetobutylicum (30), Bacillus polymyxa (31), Bacteroides succinogenes (32), Clostridium thermocellum (33) and Pseudomonas fluorescens subsp. cellulosa (34). In each case the xylanases were predominantly located intracellularly and the levels of xylanases produced from cloned systems were, in general, very low in comparison to yeast and fungal systems. A comparison of the production yields and extent of extracellular production for various cloned xylanase genes is found in Table... 

Cybinski, D. H., Layton, I., Lowry, J. B., and Dalrymple, B. P., An acetylxylan esterase and a xylanase expressed from genes cloned from the ruminal fungus Neocallimastix patriciarum act synergistically to degrade acetylated xylans. Appl Microbiol Biotechnol 1999, 52 (2), 221-5. 

Sipat, A., Taylor, K. A., Lo, R. Y., Forsberg, C. W., and Krell, P. J., Molecular cloning of a xylanase gene from Bacteroides succinogenes and its expression in Escherichia coli. Appl Environ Microbiol 1987, 53 (3), 477-81. 

Whitehead, T. R. and Hespell, R. B., Cloning and expression in Escherichia coli of a xylanase gene from Bacteroides ruminicola 23. Appl Environ Microbiol 1989, 55 (4), 893-6. 

Recombinant DNA techniques offer the means to not only enhance xylanase production but also to improve the stability and activity of the enzymes. Xylanase genes have been cloned from different microbial genera into various suitable hosts, of which E. coli features most commonly. The expression in E. coli is generally found to be lower than the parent organism, and confined to the cytoplasmic or periplasmic fractions. The absence of post-translational modifications such as glycosylation in E. coli and the intracellular accumulation of the recombinant xylanases have been suggested to be the key reasons for low levels of activity (3). 

Tian B, Xu Y, Cai W, Huang Q, Gao Y, Li X, Huang J. (2013). Molecular cloning and overexpression of an endo- 3-l,4-xylanase gene from Aspergillus niger in industrial Saccharomyces cerevisiae YS2 strain. Appl Biochem Biotechnol, 170(2), 320-328. 

Zappe H, Jones DT, Woods DR (1987) Cloning and expression of a xylanase gene from Clostridium acetobutylicum P262 in Escherichia coli. Appl Microbiol Biotechnol 27 57-63... 

Bulk Enzymes. Enzymes such as proteases, amylases, glucose isomerases, and rennin are used in food processing. Similarly proteases and Hpases are used in detergents. CeUulases and xylanases are used in the paper pulp industry. The genes for most of the enzymes used in the various commercial processes have been cloned and overexpressed. Rennin (chymosin) produced from E. coli and A. nigerhas been approved by FDA for use in the dairy industry. 

The tomatinase gene from F. oxysporum f. sp. lycopersici has been cloned recently [34]. This gene encodes a protein that has no sequence homology to any previously described saponinase but which is highly similar to xylanases (family 10 of glycosyl hydrolases) [84, 85, 93-95]. Although F. oxysporum tomatinase does not have any detectable xylanase activity, it remains to be determined whether any of the xylanases listed in this family possesses activity against a-tomatine. In any case, it is... 

Araki, T., S. Hashikawa, and T. Morishita. 2000. Cloning, sequencing, and expression in Escherichia coli of the new gene encoding b-l,3-xylanase from a marine bacterium, Vibrio sp. Strain XY-214. Applied and Environment Microbiology 66 1741-1743. 

Suzuki, T., Kitagawa, E., Sakakibara, F., Ibata, K., Usui, K., and Kawai, K., Cloning, expression, and characterization of a family 52 beta- xylosidase gene (xysB) of a multiple-xylanase-producing bacterium, Aeromonas caviae ME-1. Biosci Biotechnol Biochem 2001, 65 (3), 487-94. 

A number of cellulase and hemicellulase genes have been cloned from Caldocel-lum saccharolyticum" into E. coli, including Avicelase, CMCase, P-glucosidase, xylanase, xylosidase and mannanase by Bergquist s group [328, 334-337]. The... 

Gat O, Lapidot A, Alchanati I, Regueros C, Shoham Y (1994) Cloning and dna sequence of the gene coding for Bacillus stearothermophilus T-6 xylanase. Appl Environ Microbiol 60 1889-18%... 

Schroen CG, Vandewiel S, Kroon PJ, Devroom E, Janssen AE, Tramper J (2000) Equilibrium position, kinetics, and reactor concepts for the adipyl-7-Adca-hydrolysis process [in process citation]. Biotechnol Bioeng 70 654-661 Schumacher G, Sizmann D, Haug H, Buckel P, BoeckA (1986) Penicillin acylase from E. coli unique gene-protein relation. Nucleic Acids Res 14 5713—5727 Shendye A, Rao M (1993) Cloning and extracellular expression in Escherichia coli of xylanases from an alkaliphilic thermophilic bacillus sp. Ncim-59. FEMS Microbiol Lett 108 297-302... 

The complete gene xylA encoding endo-l,4-p-xylanase was also cloned and sequenced. Nucleotide sequences for binding CREA and XlnR were detected in promoter region. Also a set of recombinant strains P. canescens PCXlnR displaying seven- to eightfold increase in xylanase activity were created. The fraction of xylanase in most productive strains amounted to 30-50 % of the total secreted protein (Serebryanyi et al. 2002). 

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