alpha-L-Arabinofuranosidase from Streptomyces sp. PC22: purification, characterization and its synergistic action with xylanolytic enzymes in the degradation of xylan and agricultural residues.
alpha-l-Arabinofuranosidase was purified from culture filtrates of the thermoalkaliphilic Streptomyces sp. PC22 to about 108-fold purity by (NH(4))(2)SO(4) precipitation followed by column chromatography. Its approximate molecular weight was 404kDa, with a subunit mass of approximately 79kDa. The evaluated K(m) and V(max) values with p-nitrophenyl-alpha-l-arabinofuranoside as substrate were 0.23mM and 124 U.mg(-1), respectively. The purified enzyme was optimally active at 65 degrees C and pH 6.0 and showed a mild but significant synergistic effect in combination with other xylanolytic enzymes, including xylanase, beta-xylosidase and acetyl esterase, on the degradation of oat-spelt xylan, corn cob and corn husk substrates with a 1.25, 1.32 and 1.21-fold increase in the amount of reducing sugar released, respectively, compared to the expected (additive) amounts for the individual enzymes acting alone. Sequential reactions using two xylan-backbone degrading enzymes (xylanase/beta-xylosidase) and two debranching enzymes (alpha-l-arabinofuranosidase/acetyl esterase) were also determined. The highest degree of synergy was obtained in sequential reactions with the debranching enzyme digestion preceding the xylan-backbone degrading enzymes.
Raweesri
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P
Department of Microbiology, Chulalongkorn University, Bangkok 10330, Thailand.
Riangrungrojana
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P
Pinphanichakarn
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P
D000383:Agriculture; D018554:Avena / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D018556:Crops, Agricultural / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D004795:Enzyme Stability / Q000187:drug effects; D006026:Glycoside Hydrolases / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006868:Hydrolysis / Q000187:drug effects; D008670:Metals / Q000494:pharmacology; D012037:Refuse Disposal; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*; D013379:Substrate Specificity / Q000187:drug effects; D013696:Temperature; D014990:Xylans / Q000378:metabolism*; D014995:Xylosidases / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism
D008670:Metals; D014990:Xylans; D006026:Glycoside Hydrolases; D014995:Xylosidases; C019713:alpha-N-arabinofuranosidase; D043364:Endo-1,4-beta Xylanases