松褐天牛幼虫肠道黏质沙雷氏菌培养条件与木质素降解功能  

Culture Conditions and Lignin-Degrading Function of Serratia marcescens Living in the Larval Gut of Monochamus alternatus

作　　者：傅慧静 胡霞[1] 吴松青[1] 王荣[1] 梁光红[1] 黄世国[1] 张飞萍[1] Fu Huijing;Hu Xia;Wu Songqing;Wang Rong;Liang Guanghong;Huang Shiguo;Zhang Feiping(College of Forestry, Fujian Agriculture and Forestry University ,Fuzhou 350002)

机构地区：[1]福建农林大学林学院

出　　处：《林业科学》2020年第2期106-115,共10页Scientia Silvae Sinicae

基　　金：国家重点研发计划项目(2017YFD0600105)

摘　　要：【目的】研究松褐天牛幼虫肠道内黏质沙雷氏菌木质素降解功能,为揭示松褐天牛与肠道细菌协作降解木质素的机制提供依据。【方法】以硫酸盐木质素液体培养基培养黏质沙雷氏菌,采用酶标仪微量测定法研究该菌对木质素的降解能力,考察其产木质素降解酶的种类及其变化,以及体外培养条件对该菌产优势降解酶——木质素过氧化物酶活性的影响。【结果】体外培养10天后黏质沙雷氏菌对硫酸盐木质素的累计降解率达94.12%,其中第4天的单日降解率最高,达15.16%。该菌在木质素培养基中可产木质素过氧化物酶、锰过氧化物酶、漆酶3种木质素降解酶,其中木质素过氧化物酶活性最高,然后依次是锰过氧化物酶和漆酶,前2种酶的日变化趋势与培养基中木质素的降解率相近。该菌产木质素过氧化物酶的最适培养基条件:pH5、硫酸木质素质量浓度3 g·L^-1,有机氮源、酵母膏质量浓度5 g·L^-1,Mg2+、Ca2+、Fe2+、Mn2+、K+离子质量浓度分别为0.20、0.40、0.15、0.04和0 g·L^-1。【结论】黏质沙雷氏菌具有较强的木质素降解能力,可通过产生木质素过氧化物酶和锰过氧化物酶实现其对木质素的降解功能;培养基中木质素浓度、pH值、氮源种类及其浓度、金属离子及其浓度等对其产木质素过氧化物酶的活性均有显著影响。【Objective】In order to explore the cooperative mechanism to degrade lignin between Monochamus alternatus and its gut bacteria,the lignin-degrading function of Serratia marcescens,a dominant bacterium living in the larval gut of M.alternatus,was studied.【Method】Liquid kraft lignin medium was used to cultivate this bacterium.The degradation of lignin by S.marcescens was measured by the method of microtitration and the characteristic of lignin—degradation enzyme(LiP).Meanwhile,influences of different culture conditions on enzymatic activity of Lip,a dominant lingin-degrading enzyme which was produced by S.marcescens,had been studied.【Result】It was showed that the accumulated degradation rate of the kraft lignin by S.marcescens was up to 94.12%in ten days,and the highest enzymatic activity was reached on the 4th day after inoculation.This bacterium could produced lignin peroxidase(LiP),manganese peroxidase(MnP)and laccase(Lac)in medium of lignin,and the enzymatic activity of LiP was highest,followed by MnP and Lac,and the daily variation tendency of the former two kinds of enzymes were similar with the degradation rate of lignin in the medium.The optimal medium contained 3 g·L^-1 lignin,5 g·L^-1 yeast extract as organic nitrogen sources,0.20 g·L^-1 Mg2+,0.40 g·L^-1 Ca2+,0.15 g·L^-1Fe2+,0.04 g·L^-1 Mn2+,0 g·L^-1 K+,and the optimum condition is pH value of 5.0.【Conclusion】S.marcescens had strong ability to degrade lignin through producing LiP and MnP.The LiP enzymatic activity could be significantly affected by the concentration of lignin,pH,kinds and concentrations of nitrogen source,concentrations of mental irons.

关 键 词：黏质沙雷氏菌 木质素降解酶 木质素过氧化物酶 松褐天牛 幼虫肠道 

分 类 号：S763.3[农业科学—森林保护学]