Journal article
Production of beta-xylanase and beta-xylosidase by the extremely halophilic archaeon Halorhabdus utahensis
The extremely halophilic archaeon, Halorhabdus utahensis, isolated from the Great Salt Lake, Utah, produced beta-xylanase and beta-xylosidase activities. Both enzymes were active over a broad NaCl range from near zero to 30% NaCl when tested with culture broth. A broad NaCl optimum was observed for beta-xylanase activity between 5% and 15% NaCl, while beta-xylosidase activity was highest at 5% NaCl.
Almost half of the maximum activities remained at 27%-30% NaCl for both enzyme activities. When dialyzed culture supernatant and culture broth were employed for determination of beta-xylanase and beta-xylosidase stabilities, approximately 55% and 83% of the initial beta-xylanase and beta-xylosidase activities, respectively, remained after 24 h incubation at 20% NaCl.
The enzymes were also shown to be slightly thermophilic: P-xylanase activity exhibiting two optima at 55degrees and 70degreesC, while beta-xylosidase activity was optimal at 65degreesC. SDS-PAGE and zymogram techniques revealed the presence of two xylan-degrading proteins of approximately 45 and 67 kDa in culture supernatants.
To our knowledge, this paper is the first report on hemicellulose-degrading enzymes produced by an extremely halophilic archaeon.
Language: | English |
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Publisher: | Springer-Verlag |
Year: | 2003 |
Pages: | 87-93 |
ISSN: | 14310651 and 14334909 |
Types: | Journal article |
DOI: | 10.1007/s00792-002-0299-y |
Archaea β-xylanase β-xylosidase Halophilic Halorhabdus utahensis Halostable Endo-1,4-beta Xylanases Enzyme Stability Geologic Sediments Halobacteriaceae Hydrogen-Ion Concentration Hydrolysis Kinetics Osmolar Concentration Seawater Sodium Chloride Temperature Utah Xylosidases exo-1,4-beta-D-xylosidase