The decline
was steeper when enzyme was incubated at 80 C, retaining only
35.2% activity after 1 h of incubation. At the end of 3 h, 15.4% and
4.8% enzyme activity was observed at 70 and 80 C, respectively.
The thermostability profile of endoxylanases could be further
improved using recombinant technology. Fedrova et al. (2012) reported
the optimum activity of mutant endoxylanase at pH 6.0 and
temperature 70 C with half inactivation period of 7h at 60 C when
the gene encoding endo-1,4 b-xylanase, gene xylE, from Penicillium
canescens was expressed under the control of strong promoter, bga
S (gene encoding b-galactosidase).