Covalent Immobilisation of an Aspergillus niger Derived Endo-1,4-β-Mannanase, Man26A, on Glutaraldehyde-Activated Chitosan Nanoparticles for the Effective Production of Prebiotic MOS from Soybean Meal

Abstract

An Aspergillus niger endo-1,4-β-mannanase, Man26A, was confirmed by FTIR and XRD to be immobilised on glutaraldehyde-activated chitosan nanoparticles via covalent bonding. The immobilisation (%) and activity yields (%) were 82.25% and 20.75%, respectively. The biochemical properties (pH, temperature optima, and stability) were then comparatively evaluated for both the free and immobilised Man26A. The optimal activity of Man26A shifted to a lower pH after immobilisation (pH 2.0–3.0, from pH 5 for the free enzyme), with the optimum temperature remaining unchanged (60 °C). The two enzymes exhibited identical thermal stability, maintaining 100% activity for the first 6 h at 55 °C. Substrate-specific kinetic analysis showed that the two enzymes had similar affinities towards locust bean gum (LBG) with varied Vmax values. In contrast, they showed various affinities towards soybean meal (SBM) and similar Vmax values. The immobilised enzyme was then employed in the enhancement of the functional feed/prebiotic properties of SBM from poultry feed, increasing mannooligosaccharides (MOS) quantities. The SBM main hydrolysis products were mannobiose (M2) and mannose (M1). The SBM-produced sugars could be utilised as a carbon source by probiotic bacteria; Streptococcus thermophilus, Bacillus subtilis, and Lactobacillus bulgaricus. The results indicate that the immobilised enzyme has the potential for use in the sustainable and cost-effective production of prebiotic MOS from agricultural biomass.

Production of Mannooligosaccharides from Açaí Seed by Immobilized β-Mannanase

“…Other authors who have immobilized β-mannanase have also conducted stability tests, typically for 10 cycles. However, in their studies, they observed a more pronounced decrease in activity compared to what was reported in this work [9,33]. This result demonstrates the effectiveness of the immobilization methodology and the type of support used to retain enzymatic activity.…”

“…(2022) achieved immobilization on a chitosan particle support and hydrolyzed soybean flour, identifying only mannobiose, reaching a concentration of 350 mg/L [9]. In another study, Chen et al (2023) immobilized mannanases and released 7.94 (g/L) of MOS (M2-M3) from konjac flour after 8 h of hydrolysis [33].…”

“…Mannooligosaccharides (MOS) are D-mannose oligosaccharides arranged in chains of two to ten units, linked by β-1,4 glycosidic bonds. Derived from mannan, a component of hemicellulose prevalent in various botanical sources, legumes, and seeds, MOS exhibit prebiotic properties comparable to fructooligosaccharides and inulin [9,10]. Furthermore, MOS exhibit antioxidative and anticancer properties, positioning them as a promising choice in the realms of nutrition and health [11].…”

Special Issue “Pretreatment and Bioconversion of Crop Residues II”—Introduction to the Collection

“…Pretreatment with dilute sodium hydroxide was found to be the most effective method. Finally, Anderson et al [25] report the immobilization of enzymes produced by Aspergillus niger for producing mannooligosaccharides from soybean meal. As a main conclusion, the authors state that the prebiotic potential of soybean meal-produced sugars on the growth and viability of probiotic bacteria is better than that of glucose.…”