MOESM1 of Metabolic engineering of Pichia pastoris for production of isobutanol and isobutyl acetate

Additional file 1. Supplementary information for metabolic engineering of the methylotrophic yeast pichia pastoris for production of isobutanol and isobutyl acetate

Production of high activity <i>Aspergillus niger</i> BCC4525 β-mannanase in <i>Pichia pastoris</i> and its application for mannooligosaccharides production from biomass hydrolysis

<p>A cDNA encoding β-mannanase was cloned from <i>Aspergillus niger</i> BCC4525 and expressed in <i>Pichia pastoris</i> KM71. The secreted enzyme hydrolyzed locust bean gum substrate with very high activity (1625 U/mL) and a relatively high <i>k</i>_cat/<i>K</i>_<i>m</i> (461 mg⁻¹ s⁻¹ mL). The enzyme is thermophilic and thermostable with an optimal temperature of 70 °C and 40% retention of endo-β-1,4-mannanase activity after preincubation at 70 °C. In addition, the enzyme exhibited broad pH stability with an optimal pH of 5.5. The recombinant enzyme hydrolyzes low-cost biomass, including palm kernel meal (PKM) and copra meal, to produce mannooligosaccharides, which is used as prebiotics to promote the growth of beneficial microflora in animals. An <i>in vitro</i> digestibility test simulating the gastrointestinal tract system of broilers suggested that the recombinant β-mannanase could effectively liberate reducing sugars from PKM-containing diet. These characteristics render this enzyme suitable for utilization as a feed additive to improve animal performance.</p> <p>A recombinant β-mannanase from <i>A. niger</i> BCC4525 exhibits high activity. It produces MOS from low-cost biomass and enhance the release of reducing sugars from diet.</p