聚-γ-谷氨酸在环境中降解特性的初步研究

Degradability of Poly-γ-glutamic Acid in Environment

通过液相色谱分析聚-γ-谷氨酸(γ-PGA)在环境水样和土样中的降解率,以及降解产物谷氨酸的生成量,研究γ-PGA在环境中的降解特性。研究表明:γ-PGA在环境水样中的降解较慢,10d后,0.5%γ-PGA在鱼塘水样中仅降解了1.6%,谷氨酸的含量也仅为120mg/kg。γ-PGA在环境土样中降解明显,γ-PGA在土壤中放置20d,仅保存了7.6%,而谷氨酸含量达到了3.2mg/g土样。γ-PGA在灭菌土壤中降解的半衰期是未灭菌土壤的3.7倍,这说明γ-PGA在环境土样中的降解主要是微生物的作用。从土壤中分离的γ-PGA生产菌株B. subtilis CCTCC202048能降解γ-PGA,通过PCR扩增从该菌株中得到了γ-PGA降解酶基因。该研究将为γ-PGA在环境中的使用奠定理论基础。

Degradability of poly-γ-glutamic acid （γ-PGA） in water environment and soil environment was studied by measuring the variety of poly-γ-glutamic acid and glutamic acid with high performance liquid chromatography. Results showed that the degradation rate of γ-PGA was small in water environment, with only 1.6% γ-PGA degraded and content of glutamic acid 120mg/kg after 10d while the degradation rate of γ-PGA was great in soil, with only 7.6% γ-PGA reserved and content of glutamic acid up to 3.2mg/g after 20d. Half-life of γ-PGA in sterilized soil was 3.7times that of in unsterilized soil, which indicated that the degradation of γ-PGA in the soil was mainly due to microbial action. B.subtilis CCTCC202048 producingγ-PGA, isolated from soil, can degrade γ-PGA and γ-PGA depolymerase gene was identified by PCR. The study would lay a foundation for the application of γ-PGA in agriculture.