Optimization of Xylanase Production by Filamentous Fungi in Solid-State Fermentation and Scale-up to Horizontal Tube Bioreactor

Abstract

were grown on corncob to produce cell wall polysaccharide-degrading enzymes, mainly xylanases, by solid-state fermentation (SSF). A. niger CECT 2700 produced the highest amount of xylanases of 504±7 U/g dry corncob (dcc) after 3 days of fermentation. The optimization of the culture broth (5.0 g/L NaNO 3 , 1.3 g/L (NH 4) 2 SO 4 , 4.5 g/L KH 2 PO 4 , and 3 g/L yeast extract) and operational conditions (5 g of bed loading, using an initial substrate to moistening medium of 1:3.6 (w/v)) allowed increasing the predicted maximal xylanase activity up to 2,452.7 U/g dcc. However, different pretreatments of materials, including destarching, autoclaving, microwave, and alkaline treatments, were detrimental. Finally, the process was successfully established in a laboratory-scale horizontal tube bioreactor, achieving the highest xylanase activity (2,926 U/g dcc) at a flow rate of 0.2 L/min. The result showed an overall 5.8-fold increase in xylanase activity after optimization of culture media, operational conditions, and scale-up.

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

“…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).…”

“…Although xylan is the main inducer for the production of xylanase, it is an expensive substrate and thus economically nonviable for the industry. Consequently, the use of pulp industry wastewater represents the possibility of using a low-cost substrate (Fang, Chang, Hsieh, & Fang, 2007;Bakri et al, 2008;Pérez-Rodríguez et al, 2014). Current study aims at optimizing xylanase production by Aspergillus niger using pulp industry wastewater, with independent variables analyzed by factorial design.…”

Enhancement of thermoalkaliphilic xylanase production by Pichia pastoris through novel fed-batch strategy in high cell-density fermentation

“…CS802, Aspergillus niger CECT 2700, etc.) for xylanase production [35–37]. However, the xylanase activity was decreased by 70.31% with adding 2% (w/v) corncob to P. pastoris culture in this study (Fig.…”

Biochemical properties of a new thermo- and solvent-stable xylanase recovered using three phase partitioning from the extract of Bacillus oceanisediminis strain SJ3

“…The hydrolysis of pulp bound hemicelluloses releases the lignin in the pulp, reducing the amount of chlorine required for conventional chemical bleaching and minimizing the toxic, chloroorganic waste. Therefore, xylanases from alkalophilic bacteria and actinomycetes and fungi have been studied widely (Perez-Rodriguez et al 2014; Wang et al 2014). However, large scale cultivation of fungi and actinomycetes is often difficult because of their slow generation time, coproduction of highly viscous polymers, and poor oxygen transfer (Wong et al 1997; Garg et al 2011).…”