Gene cloning, expression and characterization of a new cold-active and salt-tolerant endo-beta-1,4-xylanase from marine Glaciecola mesophila KMM 241.
Appl Microbiol Biotechnol
; 84(6): 1107-15, 2009 Oct.
Article
in En
| MEDLINE
| ID: mdl-19506861
Although a lot of xylanases are studied, only a few xylanases from marine microorganisms have been reported. A new xylanase gene, xynA, was cloned from marine bacterium Glaciecola mesophila KMM 241. Gene xynA contains 1,272 bp and encodes a 423-amino acid xylanase precursor. The recombinant xylanase, XynA, expressed in Escherichia coli BL21 is a monomer with a molecular mass of 43 kDa. Among the characterized xylanases, XynA shares the highest identity (46%) to the xylanase from Flavobacterium sp. strain MSY2. The optimum pH and temperature for XynA is 7.0 and 30 degrees C. XynA retains 23% activity and 27% catalytic efficiency at 4 degrees C. XynA has low thermostability, remaining 20% activity after 60-min incubation at 30 degrees C. Its apparent melting temperature (T (m)) is 44.5 degrees C. These results indicate that XynA is a cold-active xylanase. XynA shows a high level of salt-tolerance, with the highest activity at 0.5 M NaCl and retaining 90% activity in 2.5 M NaCl. It may be the first salt-tolerant xylanase reported. XynA is a strict endo-beta-1,4-xylanase with a demand of at least four sugar moieties for effective cleavage. It efficiently hydrolyzes xylo-oligosaccharides and xylan into xylobiose and xylotriose without producing xylose, suggesting its potential in xylo-oligosaccharides production.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Alteromonadaceae
/
Xylan Endo-1,3-beta-Xylosidase
Language:
En
Journal:
Appl Microbiol Biotechnol
Year:
2009
Document type:
Article
Affiliation country:
China
Country of publication:
Alemania