Enhanced Enzymatic Performance of β-Mannanase Immobilized on Calcium Alginate Beads for the Generation of Mannan Oligosaccharides

Abstract

Mannan oligosaccharides (MOSs) are excellent prebiotics that are usually obtained via the enzymatic hydrolysis of mannan. In order to reduce the cost of preparing MOSs, immobilized enzymes that demonstrate good performance, require simple preparation, and are safe, inexpensive, and reusable must be developed urgently. In this study, β-mannanase was immobilized on calcium alginate (CaAlg). Under the optimal conditions of 320 U enzyme addition, 1.6% sodium alginate, 2% CaCl2, and 1 h of immobilization time, the immobilization yield reached 68.3%. The optimum temperature and pH for the immobilized β-mannanase (Man-CaAlg) were 75 °C and 6.0, respectively. The Man-CaAlg exhibited better thermal stability, a high degree of pH stability, and less substrate affinity than free β-mannanase. The Man-CaAlg could be reused eight times and retained 70.34% of its activity; additionally, the Man-CaAlg showed 58.17% activity after 30 days of storage. A total of 7.94 mg/mL of MOSs, with 4.94 mg/mL of mannobiose and 3.00 mg/mL of mannotriose, were generated in the oligosaccharide production assay. It is believed that this convenient and safe strategy has great potential in the important field of the use of immobilized β-mannanase for the production of mannan oligosaccharides.

Production of Mannooligosaccharides from Açaí Seed by Immobilized β-Mannanase

“…This trend of shifting the optimal pH toward less acidic conditions was also noted Dhiman et al (2020) for β-mannanase supported on cyclodextrin grafted with sodium ginate [22], and by Chen et al (2023), who also immobilized β-mannanase on sodium ginate [33]. This alteration in the optimal pH is typically associated with variations in ionic environment surrounding the enzyme's active sites.…”

“…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]. The present study demonstrates superior results compared to the above-mentioned works.…”