Optimization Of Xylanase Production And Partial Characterization Of Xylanase

Optimized the fermentation conditions of the Trichoderma viride collected in our lab.The optimization result through experiment is described as below: 10%corncob-powder of total medium volume as the carbon source, 0.5% peptone asthe nitrogen source, 20% triangle flask bulk for medium volume, 2% inoculatingvolume, initializing medium pH to 4.0, 30℃, 180 rpm to ferment for 72 hours.The fermentation broth was purified through centrifuging and salting out with 50%ammonium sulfate. The activity and the specific activity of the obtained crudxylanase is 449U/mL and 184.9U/mg respectively. Basic enzymatic characteristicsof obtained enzyme were studied. The optimal temperature is 60℃, and it showsrelatively good thermal stability under 40℃; The optimal pH condition is 4.0, andit is stable under acid environment but as the ascensus of pH value its stabilitydecrease quickly. The influences of some metal ions on xylanase activity were alsostudied. Lower concentration of the ions such as Cu²⁺,Al³⁺,Co²⁺ and Cr³⁺ inhibitthe enzyme activity. Especially the Cu²⁺, it has a relatively strong inhibit on theenzyme and it inhibited 41% of the activity. As the ascensus of the concentration,the inhibition attenuated. The inhibition of 2mmol/L Cu²⁺ degraded to 8 %. Theinfluences of other metal ions such as K⁺,Ba²⁺,Ca²⁺,Mn²⁺,Fe³⁺,Mg²⁺on xylanaseare not obvious Besides, we investigated the thermal and acid stability of xylanase after itsincubation with different concentration of protecttive solute(sucrose,maltose andglucose). The protective solute can improve the thermal and acid stability ofxylanase. The effects of sucrose are the best, it can retain most of the activity at theconcentration of 3ï¼…. At higher concentration the effects are not obvious any more.