漆酶/天然介体系统对碱木质素粒径和官能团变化的影响

以2,2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)为介体测定漆酶活性,在最适pH为4、温度为40℃下测得比酶活为2096.3 U/g。在此基础上,以漆酶和天然介体香草醛构建漆酶/介体系统(LMS)处理木质素,探究粒径和官能团变化,优化反应条件(时间、温度、pH和酶量)。结果表明:经LMS处理的木质素粒径可比对照组降低49.17%;在本试验条件下确定的优化工艺条件为反应时间3 h、pH3.5、温度35℃、酶量3 U/g,时间和pH值为主导因素;处理前后木质素的官能团种类未发生改变,但—OH、—CH3、—CH2—、—OCH3等基团数量出现变化。相较于仅介体处理,LMS可更好地减小木质素粒径,同时更多地保留—OH、—OCH3等活性基团。

Effects of Laccase-natural Mediator System on Particle Sizes and Functional Groups Changes of Alkali Lignin

The activity of laccase was determined with 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt(ABTS)as a mediator,and the specific activity was 2096.3 U/g at the optimum pH of 4 and temperature of 40℃.Based on this,the laccase-mediator system(LMS)was prepared with laccase and vanillin as the natural mediator and used to treat alkali lignin.The particle sizes and functional groups of lignin were investigated and the optimal parameters of reaction conditions(time,temperature,pH and dosage of laccase)were studied.The results suggested that the particle size of lignin treated by LMS could decrease 49.17%compared with the control group.Under the conditions of this experiment,the optimal process parameters of reaction were duration of 3 hours,pH of 3.5,temperature of 35℃and laccase dosage of 3 U/g,in which time and pH value were the main factors.There was no significant alteration in functional groups types of lignin before and after treatment,but the amount of functional groups such as—OH,—CH3,—CH2—and—OCH3 changed.Compared with the treatment with only mediator,LMS treatment could reduce the particle sizes of alkali lignin better,and retain more active functional groups such as—OH and—OCH3.