聚乳酸的酶促降解研究  

Enzymatic Degradation of Poly(Lactic Acid) Film by Proteinase K

作　　者：毛海龙[1] 刘慧芳[1] 王战勇[1] 

机构地区：[1]辽宁石油化工大学化学化工与环境学部,辽宁抚顺113001

出　　处：《工程塑料应用》2014年第2期70-73,共4页Engineering Plastics Application

基　　金：辽宁省教育厅科学研究项目(L2011060)

摘　　要：采用蛋白酶K对聚乳酸(PLA)薄膜进行酶促降解,考察了溶液起始pH值、降解温度、蛋白酶K浓度、降解时间等因素对薄膜降解率的影响,并研究了后3种因素对溶液pH值变化趋势的影响。利用扫描电子显微镜(SEM)和X射线衍射(XRD)仪观察和分析了薄膜降解前后的形态和结晶情况。结果表明,随溶液起始pH值、降解温度、蛋白酶K浓度的增加,PLA薄膜降解率先增大后降低,随着降解时间的增加,PLA薄膜的降解率先逐渐增大,在6 h后趋于稳定;获得了最合适的降解工艺参数:溶液起始pH值为9.0、降解温度为160℃、蛋白酶K浓度为0.5 mg/mL、降解时间为6 h,在此条件下蛋白酶K对PLA薄膜的降解率可达(94.3±0.8)%。溶液pH值随后3种因素的变化趋势与降解率大体相反,间接反映了PLA薄膜在降解过程中生产了大量单体乳酸。SEM观察到降解后的薄膜表面形成了孔洞及蚀痕。XRD分析结果表明降解后薄膜的相对结晶度降低,晶体区域发生降解。Enzymatic degradation of Poly （lactic acid） （PLA） films were done by using proteinase K,then the effects factors, such as original pH of solution,degradation temperature,proteinase K concentration,and degradation time,on degradation rate of the films were studied. The effects of the latter 3 factors on the change conditions of pH of solution in the degradation process of PLA were studied and the morphology and crystallization conditions before and after degrading were also studied by SEM and XRD. The results show that with the increase of the original pH of solution,degradation temperature and proteinase K concentration,the degradation rate increases firstly and decreases lastly,moreover,with the increase of the degradation time,the degradation rate first increases and tends to become stable after 6 h. The optimized degradation process parameters were gained as follows：original pH of solution is 9.0,degradation temperature is 60℃,proteinase K concentration is 0.5 mg/mL,and degradation time is 6 h. Under this condition,the degradation rate of the film reaches （94.3±0.8）%. The change conditions of the pH of solution is opposite comparing with those of the degradation rate in general,which indirectly indicates that numerous lactic acid are generated in the degradation process. The holes and etching marks on the surface of the films after degradation are observed by SEM. XRD analyzing results indicates that relative crystallinity of the films decreases after degradation and the crystal areas are degraded by proteinase K.

关 键 词：聚乳酸 蛋白酶K 生物降解 

分 类 号：O631.3[理学—高分子化学]