Bioprocess and biotechnology: effect of xylanase from Aspergillus niger and Aspergillus flavus on pulp biobleaching and enzyme production using agroindustrial residues as substract

Abstract

This study compares two xylanases produced by filamentous fungi such as A. niger and A. flavus using agroindustrial residues as substract and evaluated the effect of these enzymes on cellulose pulp biobleaching process. Wheat bran was the best carbon source for xylanase production by A. niger and A. flavus. The production of xylanase was 18 and 21% higher on wheat bran when we compare the xylanase production with xylan. At 50°C, the xylanase of A. niger retained over 85% activity with 2 h of incubation, and A. flavus had a half-life of more than 75 minutes. At 55°C, the xylanase produced by A. niger showed more stable than from A. flavus showing a half-life of more than 45 minutes. The xylanase activity of A. niger and A. flavus were somehow protected in the presence of glycerol 5% when compared to the control (without additives). On the biobleaching assay it was observed that the xylanase from A. flavus was more effective in comparison to A. niger. The kappa efficiency corresponded to 36.32 and 25.93, respectively. That is important to emphasize that the cellulase activity was either analyzed and significant levels were not detected, which explain why the viscosity was not significantly modified.

<b>Reuse of wastewater from pulp industry for the optimization of fungal xylanase production

“…However, the literature shows that the ideal pH range for xylanase production lies between 4.0 and 6.0. Xylanase activity decreased at alkaline pH for the two types of wastewater, corroborating data in the literature (De Alencar Guimarães et al, 2013). Temperature was also an influential factor in enzymatic production and it may be related to thermophile or mesophile characteristics of the fungus used.…”

“…The best temperatures for fungal xylanases lie between 30 and 60°C. Higher temperatures are usually associated with a short period production, unlike conditions in current study, where high temperatures were associated with a long period of production (7 days) with negative influence of the 40-60°C temperature range, indicating the mesophilic characteristic of A. niger used (Rizzatti, Sandrim, Jorge, Terenzi, & Polizeli, 2004;Chandra & Sankhwar, 2011;De Alencar Guimarães et al, 2013;Pérez-Rodríguez et al, 2014).…”

Gene Expression and Molecular Characterization of a Xylanase from Chicken Cecum Metagenome

“…The enzyme stability at different pH was determined by preincubating XynA MG1 in different buffers from pH 3.0 to 11.0 (with 1 pH unit interval) for 30 min and 60 min at 25°C. Then, the remaining activities of the enzyme were measured under standard condition [20]. …”

Bioprocess development for production of a process-apt xylanase with multifaceted application potential for a range of industrial processes

“…Plackett-Burman design (Design-Expert 6.0 Stat-Ease, Inc., Minneapolis, USA) was used for screening of eight process variables for their influence on xylanase production. The process variables screened at their respective lower and higher levels (indicated in parentheses) were: wheat bran (0.1-2% w/v), yeast extract (0.1-0.5% w/v), soybean meal (0.5-2% w/v), KH 2 PO 4 (0.05-2% w/v), MgSO 4 , (0.01-0.1% w/v), Tween-80 (0.02-0.05% w/v), incubation time (24-120 h) and medium pH (6)(7)(8)(9). A set of 12 experimental trials was generated, and experiments were performed, and the resultant response i.e.…”

“…The Kappa number was determined [9] by following the steps approved by the Pulp Properties Committee of the Process and Product Quality Division of Technical Association of the Pulp and Paper Industry (TAPPI). Sample was conditioned prior to weighing for 20 min, and then 1.0 g of pulp specimen which consumes approximately 50% of the potassium permanganate solution was weighed.…”