VOLUME 16 NUMBER 1 (January to June 2023)

Louelle Sheryl G. Albia*¹, Sheryl Lozel B. Arreola¹, Adonis A. Yanos¹, Thu-Ha Nguyen², and Dietmar Haltrich²

¹Institute of Chemistry, University of the Philippines Los Baños (UPLB),
      Philippines
²Food Biotechnology Laboratory,
      Department of Food Science and Technology,
      University of Natural Resources and Life Sciences (BOKU)
      Vienna, Austria

Mannooligosaccharides (MOS) is a prebiotic produced by the hydrolysis of mannans and promotes gut health. One route in producing MOS is via enzymatic method, which employs microbial enzyme (e.g., β-mannanase) for mannan hydrolysis. In this work, we investigated the stability and propensity of β-mannanase from Bacillus licheniformis (BlManB) overexpressed in Lactiplantibacillus plantarum WCSF1 towards β-MOS production using several mannan sources. We also determined the fermentation conditions for optimal enzyme production in the food-grade system. Maximal crude enzyme yield was obtained (17.3 ± 1.2 kU per liter of fermentation broth with specific activity of 194 U/mg protein) by maintaining the pH at 6–6.5 at fermentation. Crude BlManB is stable at storage conditions of -20°C and 4°C. The crude overexpressed enzyme was also stable and active at conversion conditions (30 °C and 37 °C) in the presence of 2 mM dithiothreitol (DTT) . Analysis by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) indicated that the crude enzyme produced known linear MOS of 235.88 mg/g using locust bean gum, 121.63 mg/g using copra meal, 71.71 mg/g using guar gum, 21.33 mg/g using spent coffee ground, and 86.76 mg/g using konjac glucomannan. The study has also shown that crude BlManB overexpressed in L. plantarum WCSF1 could be efficiently used to produce food-grade MOS.