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Xylanases: from biology to biotechnology.
- Source :
-
Biotechnology & genetic engineering reviews [Biotechnol Genet Eng Rev] 1996; Vol. 13, pp. 101-31. - Publication Year :
- 1996
-
Abstract
- Xylan is the main carbohydrate found in the hemicellulosic fraction of plant tissues and accounts for one third of all renewable organic carbon available on earth. Xylanase, the major component of an enzymatic consortium, acts in nature by depolymerizing xylan molecules into monomeric pentosan units that are used by bacterial and fungal populations as a primary carbon source. Xylanase producers have been isolated from all ecological niches where plant material is deposited, and microorganisms often contain multiple loci encoding overlapping xylanolytic functions. The numerical excess of genes and the extensive sharing of structural features within beta-glycanase families suggests that extensive gene duplication and conversion events have occurred during xylanase evolution. Hydrolysis of beta-glycosidic linkages is sponsored by a general acid catalytic reaction common to all glycanases, whereas substrate recognition is specified by subsites that interact with adjacent glycosyl units. Under natural conditions xylanases are inducible by the products of their own action and subject to carbon catabolite repression. Bleaching paper pulps with xylanases is the first successful commercial application for these enzymes. The recovery of cellulosic textile fibers is the next logical application and bioconversion of biomass into fuels and chemicals, remains the ultimate target. Recent developments have shown that metabolic pathways can be transferred from one organism to another and proteins can be modified to gain conformational stability, suggesting that naturally occurring systems can be custom engineered to the situation in the fermentation tank. Thus, biotechnologies developed to transform biomass into marketable products that gradually substitute materials derived from non-renewable resources are becoming commercially worthwhile.
- Subjects :
- Bacteria enzymology
Bacteria genetics
Biotechnology
Ecosystem
Fungi enzymology
Fungi genetics
Gene Expression Regulation
Molecular Structure
Paper
Protein Engineering
Substrate Specificity
Textiles
Xylan Endo-1,3-beta-Xylosidase
Xylans chemistry
Xylans metabolism
Xylose metabolism
Xylosidases chemistry
Xylosidases genetics
Xylosidases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0264-8725
- Volume :
- 13
- Database :
- MEDLINE
- Journal :
- Biotechnology & genetic engineering reviews
- Publication Type :
- Academic Journal
- Accession number :
- 8948110
- Full Text :
- https://doi.org/10.1080/02648725.1996.10647925