生物多样性、生物勘探与发展杂志

Optimisation of Medium Formulation and Growth Conditions for Xylanase Production by Aspergillus brasiliensis in Submerged Fermentation (SmF)

Abstract

Hooi Ling Ho and Jamila Said Hood

Objective: There has been much concern and immense importance on xylanase due to its potential industrial applications in the manufacturing of pulp and paper, baking, food and beverages, textile and animal feeds production. There are continuously endeavors to turn xylanase into a profitable market with lower production costs using optimum fermentation medium and growth conditions. Thus, the main objectives of this study were to determine the optimum medium formulation and growth conditions for the production of xylanase by Aspergillus brasiliensis ATCC 16404 and to elucidate the correlation of xylanase synthesis with biomass, pH and protein concentration in submerged fermentation (SmF).

Methods: The effect of various carbon sources: sucrose, glucose, maltose, galactose, glycerol, lactose and ethanol and nitrogen sources: yeast extract, urea, peptone, ammonium sulphate, ammonium nitrate, ammonium chloride and sodium nitrate on xylanase activity were examined to obtain the optimum medium formulation for xylanase activity by A. brasiliensis. In addition, growth temperatures of 28 to 36°C and initial pH medium of 3 to 11 were also examined to elucidate the optimum growth conditions for the production of xylanase.

Results: The highest xylanase activity of 39.567 U/mL at 72 h was obtained using sucrose and yeast extract as the optimised carbon and nitrogen sources. Our results also showed that 30°C and pH 6.5 were the optimum growth condition of A. brasiliensis for xylanase synthesis. 38.528 U/mL of xylanase activity was observed at 72 h when the initial pH medium was adjusted to 5.0. Nevertheless, when the initial pH medium was increased to 6.5, the xylanase synthesis increased almost 3% at 72 h.

Conclusion: Hence, in our study, the optimum medium formulation and growth conditions for the production of xylanase by A. brasiliensis in SmF was achieved by growing the fungi in medium containing sucrose and yeast extract with the initial medium pH 6.5 at 30°C.