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Enzymes including xylanase produced by microorganism sources are preferable in many industries especially in baking, food, pulp and paper. Nonetheless, the costs of enzymes production in industry are considerably astronomical. Therefore, agricultural residuals such as barley husk and wheat bran have been introduced as alternate carbon source to reduce the production cost. The aim of this study is to elucidate the enzyme activity of xylanase by Bacillus subtilis and Aspergillus brasiliensis in shake flask culture and bioreactor using barley husk and wheat bran as carbon source under batch submerged fermentation, respectively. Based on the results obtained, using barley husk as the substrate in the fermentation process, the maximum xylanase activity of 3.305±0.143U/ml by B. subtilis was detected in shake flask culture. Surprisingly, much higher activity of 13.069± 0.193U/ml was achieved in bioreactor. On the other hand, xylanase activity by A. brasiliensis was found to be 2.175±0.103 U/ml after using wheat bran as the prime carbon source in flask culture. Indeed, much higher production of 7.074±0.089U/ml was observed in batch bioreactor system. Simple and defined carbon sources including glucose and pure substrate such as xylan, for example generally pricey that would upsurge the enzyme production cost. Thus, in order to produce cost-conscious xylanase, agricultural residuals are introduced into the batch submerged fermentation process. Some agricultural residuals that are heaving with sugars and nutrients are anticipated to effectively utilize by microorganisms besides being ease accessible and cost-effective. Based on the results in this study, barley husk and wheat bran are suggested to be affordable alternate carbon source for xylanase production in industries.

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 o 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.

There are several crucial fermentation parameters including carbon source, temperature, pH medium and agitation speed used to elucidate and optimise the production of xylanase in submerged fermentation (SmF) and solid state fermentation (SsF). These parameters are determined by the types of microorganism that yield xylanase. Precisely, suitable parameters allow the proper proliferation of microorganisms to produce high concentration of xylanase. Carbon source provides prerequisite nutrients for growth of microorganisms in SmF and SsF. In order to enhance the xylanase production, cheap but effective carbon source such as agricultural extracts is generally added to supply as the prime nutrient. SsF has become a known interest to produce xylanase because of its economical process of using agricultural extracts. Thus, lower cost production of xylanase is easily achieved. Therefore, proper optimisation of fermentation parameters would able to produce the desirable xylanase at the maximum level. Additionally, optimum pH medium and temperature possess huge positive impact on the growth of microorganisms and xylanase production. Indeed, optimal pH and temperature in agitated culture show greater xylanase activity compared to non-agitated culture. Nonetheless, further increase of the optimum agitation speed would cause irregular morphology of microorganisms that ultimately lead to xylanase interference. In the present day, the demand for xylanase is rising because of its remarkable usages in vast industries. The foremost industrial application of xylanase is involved in chlorine-free bleaching process in pulp and paper industry whereby xylanase is added into the pulp to degrade xylan found within the lignin residuals. Increasing applications of xylanase in various industries have developed xylanase to become more valuable. As a result, there are continuously endeavors to transform xylanase industry into a profitable market with lower costs of production using different types of agricultural extracts at the optimal growth conditions. All these aspects are reviewed in this article. Statement of the Problem Only a few studies on the optimisation of medium formulation for the maximum microbial xylanase production have been conducted. The application of agricultural wastes as the carbon source for the industrial xylanase production are scarce and not comprehensively studied, compared and reported in submerged fermentation (SmF) and solid state fermentation (SsF). Being the simple, non-toxic and cost-effective carbon source to yield xylanase, the replacement of xylan as the substrate with agricultural extracts in SmF and SsF is of great interest particularly in industrial production. Agricultural extracts are the good alternative carbon source due to their similarity in the polymers structure of xylan, as a result, these lignocellulose residuals are suitable to use as the prime carbon source for xylanase production. Besides that, the lack of precise information of the optimum growth conditions on the microbial xylanase producti...

Objective: Xylanase production by Aspergillus species has become valuable and attractive due to its vast applications in pulp and paper, food and beverage, detergent and textiles industries. Xylanase is one of the hemicellulolytic enzymes that capable of hydrolysis of β-1,4 xylans present in the lignocellulosic materials.

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