Brazilian Archives of Biology and Technology
On-line version ISSN 1678-4324
CORDEIRO, Carlos Alberto Martins; MARTINS, Meire Lelis Leal; LUCIANO, Angélica Bárbara and SILVA, Roberta Freitas da. Production and properties of Xylanase from thermophilic Bacillus sp.. Braz. arch. biol. technol. [online]. 2002, vol.45, n.4, pp. 413-418. ISSN 1678-4324. http://dx.doi.org/10.1590/S1516-89132002000600002.
An aerobic, thermophilic, xylanolytic bacterium was isolated from local soil. The results of 16S rRNA sequence comparisons indicated that the isolate was closely related to Bacillus caldoxylolyticus and Bacillus sp strain AK1. These organisms exhibited 94% levels of ribossomal DNA sequence homology. Studies on the xylanase characterisation from liquid cultures grown on beechwood xylan revealed that the enzyme retained 100% of activity for 2 hours at temperatures ranging from 30 to 50o C, while at 60, 70 and 100o C, 10%, 11% and 29% of the original activities were lost, respectively. The optimum pH of the enzyme was found to be between 6.5 and 7.0. After incubation of crude enzyme solution for 24 hours at 25o C and at pH 5.5 to 8.0, a decrease of about 12% of its original activity was observed.
Keywords : Xylanase; thermophilic bacterium; Bacillus sp.