Purification and some properties of a thermostable xylanase from thermophilic fungus strain HG-1

• Published in: Journal of fermentation and bioengineering 1997-01, Vol.83 (5), p.478-480
• Main Authors: Ishihara, Masanobu, Tawata, Shinkichi, Toyama, Seizen
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biotechnology; CHAMPIGNON; enzymatic saccharification; Enzyme engineering; Fundamental and applied biological sciences. Psychology; FUNGI; HIDROLASAS; HONGOS; HYDROLASE; HYDROLASES; Improved methods for extraction and purification of enzymes; Methods. Procedures. Technologies; MICROORGANISME THERMOPHILE; MICROORGANISMOS TERMOFILOS; OLIGOSACARIDOS; OLIGOSACCHARIDE; OLIGOSACCHARIDES; PURIFICACION; PURIFICATION; thermophilic fungus; THERMOPHILIC MICROORGANISMS; thermostable xylanase; XILANOS; XILOSA; XYLANE; XYLANS; xylooligosaccharides; XYLOSE
• ISSN: 0922-338X
• DOI: 10.1016/S0922-338X(97)83005-X

An extracellular xylanase was purified to homogeneity from a wheat bran culture of the thermophilic fungus HG-1, an isolate from a compost heap. The enzyme had a molecular weight of 33,000 by SDS-PAGE and 31,000 by gel filtration; its isoelectric point was 6.8. The optimum temperature and pH for enzyme activity were 70°C and 4.5–5.0. The enzyme was stable in the pH range from 2 to 12 at 30°C. The K m values for birchwood xylan and oat-spelt xylan were 8.3 and 20 mg/ml, respectively. The enzyme produced xylobiose, xylotriose, and a trace of xylose as the endo products from birchwood xylan. The enzyme activity was strongly inhibited by SDS, and partially by Hg 2+, Mn 2+, Co 2+, Ca 2+, and iodoacetic acid. The enzyme hydrolyzed xylotriose to xylobiose and xylose and showed weak activity toward xylobiose.