一种耐热几丁质酶的产生及其稳定性研究

Production and Stability of a Thermostable Chitinase

摘要:

疏绵状嗜热丝孢菌(Thermomyces lanuginosus)SY2在以胶状几丁质为唯一碳源的诱导培养基中产生了胞外几丁质酶。该酶在50℃保温1 h, 酶活稳定; 65℃时半衰期为25 min; 酶液在室温下保存到12周, 残余酶活性为45％左右。该酶有较宽的pH范围, 3.0~9.0之间保持稳定, pH值为2.5时, 仍具有70％的剩余酶活性。Ca2+ 对几丁质酶的活性有显著的激活作用; 高浓度变性剂对酶有抑制作用。结果表明该酶是一种热稳定性高且耐酸碱的新型几丁质酶, 能在酸性和高温环境中发挥作用, 这些特性赋予了T. lanuginosus几丁质酶在几丁质的生物转化及其它生物技术中极大的应用优势。

Abstract:

An extracellular chitinase from Thermomyces lanuginosus SY2 was produced when SY2 was grown in mineral liquid medium containing colloidal chitin as the only carbon source. The chitinase was stable at 50℃ for 1h, and the half-life time of the enzyme at 65℃ was 25 min. when it was kept at room temperature for 12 week, the chitinase activity was retained about 45% activity. The pH stability was kept in the range 3.0-9.0, and the enzyme was able to obtain 70% of the full activity, when the enzyme was incubated in the buffer (pH 2.5). The chitinase activity was enhanced obviously by metal ion Ca2+, but inhibited under the high content chemical reagents. The results suggested that the chitinase from Thermomyces lanuginosus SY2 was a novel enzyme due to its high activity and stability under the high temperature and acid environment, which make it applicable for biotransformation and other biotechnological purposes.