Effect of β-Mannanase (Hemicell) on Growth Performance and Immunity of Broilers

Antinutritional factors and functionality of protein-rich fractions of industrial guar meal as affected by heat processing

Changes in immune and metabolic gut response in broilers fed β-mannanase in β-mannan-containing diets.

Bacillus subtilis BCC41051 producing a thermostable β-mannanase was isolated from soybean meal-enriched soil and was unexpectedly found to be thermophilic in nature. The extracellular β-mannanase (ManA) produced was hydrophilic, as it was not precipitated even with ammonium sulfate at 80% saturation. The estimated molecular weight of ManA was 38.0 kDa by SDS-PAGE with a pi value of 5.3. Optimal pH and temperature for mannan-hydrolyzing activity was 7.0 and 60°C, respectively. The enzyme was stable over a pH range of 5.0–11.5, and at temperatures of up to 60°C for 30 min, with more than 80% of its activity retained. ManA was strongly inhibited by Hg2+ (1 mM), but was sensitive to other divalent ions to a lesser degree. The gene of ManA encoded a protein of 362 amino acid residues, with the first 26 residues identified as a signal peptide. High expression of recombinant ManA was achieved in both Escherichia coli BL21 (DE3) (415.18 U/ml) and B. megaterium UNcat (359 U/ml).

Characterization, gene cloning, and heterologous expression of β-mannanase from a thermophilic Bacillus subtilis.

Paenibacillus sp. DZ3, newly isolated from Konjack field, produced β-mannanase (900 U/mL) when grown on glucomannan as a carbon source. β-Mannanase was purified 34-fold to homogeneity resulting in final recovery of 15% and specificity of 169 U/mg protein. The molecular mass was approximately 39 kDa as estimated by sodiumdodecylsulfate-polyacrylamide gel electrophoresis. Active band was observed as clear colourless area on zymogram. The optimal temperature and pH for mannanase activity was 60°C and pH 5.0, respectively. The activity was stable up to 60°C at pH 5.0 and remained stable from pH 5.0-7.0. Mannanase was highly specific towards glucomannan and galactomannan, whereas exhibited low activity towards mushroom powder. The Michaelis constant (K
 m) and maximum velocity (V
 max) for glucomannan substrate were 1.05 mg/mL and 714 U/mg, respectively. These results indicate the enzyme is attractive for industrial applications.

S. Connor-Appleton

Papers

Effects of guar meal by-product with and without beta-mannanase Hemicell on broiler performance