| Summary: | An <i>Aspergillus niger</i> 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 <i>V<sub>max</sub></i> values. In contrast, they showed various affinities towards soybean meal (SBM) and similar <i>V<sub>max</sub></i> 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; <i>Streptococcus thermophilus</i>, <i>Bacillus subtilis</i>, and <i>Lactobacillus bulgaricus</i>. 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.
|
|---|