木质素降解酶对四环素的降解可行性

A feasibility study on the degradation of tetracycline by ligninolytic enzymes

选取了使用广泛、在环境中残留量大、生物毒性大、不易被生物降解的四环素类抗生素中的四环素,考察了其被木质素过氧化物酶(LiP)和锰过氧化物酶(MnP)粗酶液体外降解的效果,证明2种酶对四环素均有较强的降解作用,并在此基础上比较了3个不同酶活(15U.L-1、40U.L-1、70U.L-1)下的降解率.结果表明,同等酶活(40U.L-1)下,LiP比MnP的降解能力强,在适宜的反应条件下,LiP对50mg.L-1四环素的降解率在5min内可达95%以上,而MnP在2h后仅达70%.对于LiP,当酶活从15U.L-1升高至40U.L-1时,降解率提高约15%,当酶活进一步升高至70U.L-1时,降解率变化不大,而提高酶活可明显提高MnP对四环素的降解率.此外,通过反应进程中补加H2O2,可以明显提高MnP对四环素的降解率.

During the recent decade, the PPCPs in water environment are becoming an emergent environmental issue that attracts more attention. Many reports showed that the common-used PPCPs in daily life had been detected in various samples from aqueous environment, among which antibiotics were more frequently detected than others. Tetracycline （TC） was regarded as the research objective in this study because of their wide application, high- solubility in water, high residual toxicity and characteristic of non-biodegradation. The strong capabilities of both crude manganese peroxidase （MnP） and crude lignin peruxidase （LiP） were figured out to degrade tetracycline in vitro. Upon this, three different enzyme activities （15 U·L^-1, 40 U·L^-1, 70 U·L^-1 ） were investigated under selected reaction conditions. The results illustrated that LiP had a stronger degrading ability than MnP towards TC. When the enzyme activity was 40 U·L^-1 and the TC concentration was 50 mg·L^-1, the degradation percentage by LiP could reach about 95% in five minutes while it could just reach 70% in two hours by MnP. The degradation percentage was enhanced by about 15% when the enzyme activity was increased from 15 U·L^-1 to 40 U·L^-1 for LiP. However, it did not change much when the enzyme activity was increased to 70 U·L^-1. While with the increasing MnP activity, the degradation rate of TC increased distinctively. In addition, H202 additional supply during the reaction process could obviously improve the degradation of TC by MnP.