Optimization of β-1,4-Endoxylanase Production by an Aspergillus niger Strain Growing on Wheat Straw and Application in Xylooligosaccharides Production

Abstract

Plant biomass constitutes the main source of renewable carbon on the planet. Its valorization has traditionally been focused on the use of cellulose, although hemicellulose is the second most abundant group of polysaccharides on Earth. The main enzymes involved in plant biomass degradation are glycosyl hydrolases, and filamentous fungi are good producers of these enzymes. In this study, a new strain of Aspergillus niger was used for hemicellulase production under solid-state fermentation using wheat straw as single-carbon source. Physicochemical parameters for the production of an endoxylanase were optimized by using a One-Factor-at-a-Time (OFAT) approach and response surface methodology (RSM). Maximum xylanase yield after RSM optimization was increased 3-fold, and 1.41- fold purification was achieved after ultrafiltration and ion-exchange chromatography, with about 6.2% yield. The highest activity of the purified xylanase was observed at 50 °C and pH 6. The enzyme displayed high thermal and pH stability, with more than 90% residual activity between pH 3.0–9.0 and between 30–40 °C, after 24 h of incubation, with half-lives of 30 min at 50 and 60 °C. The enzyme was mostly active against wheat arabinoxylan, and its kinetic parameters were analyzed (Km = 26.06 mg·mL−1 and Vmax = 5.647 U·mg−1). Wheat straw xylan hydrolysis with the purified β-1,4 endoxylanase showed that it was able to release xylooligosaccharides, making it suitable for different applications in food technology.

Enhanced Production, Cloning, and Expression of a Xylanase Gene from Endophytic Fungal Strain Trichoderma harzianum kj831197.1: Unveiling the In Vitro Anti-Fungal Activity against Phytopathogenic Fungi

“…was 55 °C [ 63 , 64 , 65 , 66 , 67 ]. Lower and higher temperatures reduce the specific activities for the reason that the thermal effects of such temperatures on both the growth of microorganisms and the rate of enzymatic reaction inside the cells imitate the vital construction of the enzyme [ 68 , 69 ].…”

Harnessing Mucor spp. for Xylanase Production: Statistical Optimization in Submerged Fermentation Using Agro-Industrial Wastes

“…RSM optimization of xylanase yield by Aspergillus niger 3-fold and 1.41-fold purification was attained with about 6.2% yield, and the highest activity of the purified xylanase was observed at pH 6 and 50°C. The produced xylanase exhibited high thermal and pH stability, with more than 90% residual activity between 30 and 40°C and pH 3-9 after incubation of 24 h, with half-lives of 30 min at 50 and 60°C [ 43 ]. Liet al [ 36 ] reported a temperature range of 50-60°C suitable for the industrial application of xylanase from P. oxalicum ZH-30.…”

Pichia pastoris Mediated Digestion of Water-Soluble Polysaccharides from Cress Seed Mucilage Produces Potent Antidiabetic Oligosaccharides

“…The free inoculum of the yeasts ( P. pastoris and P. kudriavzevii ) was cultured in YPD (yeast extract, peptone and dextrose) media for 24 to 48 h, and the cells were counted manually using a Neubauer chamber under a light microscope [ 62 ]. Further, 1 × 10 5 yeast cells/mL were added to fermentation media containing 1% cress seed mucilage polysaccharides as a carbon source and 1 g/L, ammonium chloride (NH 4 Cl) as a nitrogen source.…”