一株嗜热子囊菌产生的碱性耐热过氧化氢酶及其应用潜力

研究了一株嗜热子囊菌产过氧化氢酶的摇瓶发酵条件 ,并对其在纺织工业中的应用潜力进行了评价。以2 0g L糊精和 1% (V V)乙醇为混合碳源时 ,过氧化氢酶酶活达到 15 94u mL ,比以糊精和乙醇单独为碳源时过氧化氢酶的活力之和还高 2 3%。改变培养基的初始pH、提高发酵液中的溶氧水平及添加外源过氧化氢 ,过氧化氢酶的产量进一步提高到 2 76 2u mL ,比优化前提高了 5 8倍。将嗜热子囊菌的过氧化氢酶同来源于牛肝、黑曲霉的过氧化氢酶进行了热 (70℃ ,80℃ ,90℃ )、碱 (pH 9 0 ,pH 10 0 ,pH 11 0 )稳定性的比较。结果显示 ,产自嗜热子囊菌的过氧化氢酶对高温和强碱性的耐受性能明显优于其它来源的酶 ,在纺织染整工艺中具有良好的应用潜力。

Degradation behaviors,thermostability and mechanical properties of poly(ethylene terephthalate)/polylactic acid blends

It is difficult for polyethylene terephthalate （PET） to degrade,which caused severe pollution.In this work,polylactic acid （PLA） was introduced to improve the degradation of PET.PET/PLA was synthesized by extrusion blending.The thermal,crystalline and mechanical properties of blends were investigated with TGA,DSC,WAXD and universal testing machine.The degradation of the blends in soil,acid and alkaline buffer solutions was assessed,respectively.It was found that the introduction of a little PLA promoted crystallization of PET during injection molding process.The starting decomposition temperature lowered from 412.1 ℃ of pure PET to 330.4 ℃ at 50% PLA content,tensile and bending strength of blends gradually decreased with the PLA content increasing,while the degradation rate improved.Alkaline environment was most beneficial for blends to degrade.The degradation mechanism was discussed.