Production, Purification And Characteristic Of β-mannanase

β-mannanase was widely used in food, feed and functional oligosaccharide industries. Inthis paper, the production, purification and charaction of β-mannanase were studied, a prelimi-nary study of mannan-oligosaccharides (MOS) preparation by β-mannanase was also investigat-ed. The main results are as follows:The effects of medium composition such as carbon source, nitrogen source and C/N werelargely on β-mannanase production.Microcrystalline cellulose (MCC) which is the structuralanalogue of β-mannanase substrats was the best inducer for Trichoderma reesei β-mannanase.The results showed that β-mannanase production was carried out in the medium consist of20.0g/L MCC as carbon source, nitrogen from ammonium sulfate to that from urea was1:1asnitrogen source and the C/N was4. The maximal β-mannanase4.48U/mL was obtained andβ-mannosidase activity was0.04U/mL in96h.The glucomannan was hydrolyzed by β-mannanase of T. reesei for24h, the hydrolysisyield was72.98%and the selection of β-mannanase on mannan-oligosaccharides was62.22%.The endo-β-mannanase of T. reesei was purificated by20~50%ammonium sulfateprecipitation, Source15Q anion-exchange chromatography and Superdex75Prep Grad gelfiltration, the electrophretically pure component was obtained and the activity recovery was31.82%compared with crude enzyme purified5.97-fold.The β-mannosidase of T. reesei was purificated by60%ammonium sulfate precipitationand Source15Q anion-exchange chromatography, the electrophretically pure component wasobtained and the activity recovery was14.16%compared with crude enzyme purified56.19-fold.The optimum pH value of endo-β-mannanase and β-mannosidase was3.8and3.2, the pHstability range of endo-β-mannanase and β-mannosidase was3.2~6.8and2.6~5.0, respectively.The optimum reaction temperature of endo-β-mannanase and β-mannosidase was75℃and65℃, the thermal stability range of endo-β-mannanase and β-mannosidase was45~65℃and35~55℃, respectively.The Kmand Vmaxvalues of endo-β-mannanase were5.23mg/mL and3.03U/mg protein forlocust bean gum as substrate, respectively. The Kmand Vmaxvalues of β-mannosidase were1.93mg/mL and0.84U/mg protein for pNPM as substrate, respectively.