Production of highly thermostable xylanase by a wild strain of thermophilic fungus Thermoascus aurantiacus and partial characterization of the enzyme

Production of xylanase and CMCase on solid state fermentation in different residues by Thermoascus aurantiacus miehe

“…It is accept that conditions of growth and the nature of medium may stabilize the enzyme against thermal denaturation. The presence of protease induced by different composition of the medium may also affect the enzyme stability (8,9).…”

“…difference in level of enzyme production by different raw material is determined by many factors involved in the process, such as the presence of activator or inhibitor, surface area, diffusion of catabolite, pretreatment, content and sugar composition of this substrate (3,8). In this study, despite of using different substrates the fixed time (4 days) was used, and is possible that the fungus might have a different lag phase, regarding to some of these substrates, in this case, if that substrate was sampled later a higher enzyme concentration might have been achieved.…”

“…Different strains of the Thermoascus aurantiacus fungus have been reported to be good producers of thermostable endoglucanase and/or xylanase (8)(9)(10)(13)(14)(15)(16)22,(24)(25)(26), however there are few accounts of simultaneous production of CMCase and xylanase by this fungus on solid state fermentation.…”

“…The employment of thermostable enzymes to carry out hydrolysis at higher temperatures is advantageous because it increases the speed of reaction and avoids microbial contamination contributing to increase technical and economical viability of the process (8).…”

Preparation of levoglucosan by pyrolysis of cellulose and its citric acid fermentation

“…In general, the single-parameter method, a single-dimensional search which involves changing one variable while ®xing others at a certain level, is laborious and time consuming, especially when the number of variables is large. An alternative and e ective approach is the response surface technique (Carvalho et al, 1999;Gomes et al, 1994;Lopez et al, 2000) which involves three major steps: performing the experiments by the approach of Box±Behnken design or central composite design, estimating the coe cients in a mathematical model and predicting the response and checking the adequacy of the model. In this paper, we used response surface technique to optimize reaction parameters.…”