一株叶黄素高效降解菌株的筛选、鉴定及其降解产生香料物质的条件优化

Screening and identification of an efficient lutein-degrading strain and optimization of the culture conditions of its degradation of lutein

叶黄素生物降解产物中含有环柠檬醛、β-紫罗兰酮和二氢猕猴桃内酯等重要香味物质,目前能够应用于叶黄素生物降解的酶类和菌株较少。本研究从烟田土壤中分离得到一株高效降解叶黄素菌株,经典形态学和16S rDNA进化树分析,鉴定该菌株为Enterobacter tabaci strainβ7。在单因素试验基础上采用响应面试验得出该菌株降解叶黄素最佳培养条件,即为蔗糖31.97 g/L,硝酸钠3.18 g/L,酵母粉6.88 g/L和初始pH值为6.91,叶黄素降解率从85.71%提高到93.17%。GC-MS结果表明该菌叶黄素降解产物主要为β-环柠檬醛(0.75%)、5,6-环氧-β-紫罗兰酮(2.59%)、3-羟基-β-紫罗兰酮(1.69%)、β-紫罗兰酮(1.21%)、4-羟基-β-紫罗兰酮(0.89%)和二氢弥猴桃内酯(1.03%)等香料物质。该研究结果为叶黄素降解提供新型菌株资源,也为叶黄素降解产生香料物质打下理论和应用基础。

Lutein biodegradation products contain cyclocitral,β-Ionone,dihydrokiwi lactone and other important fragrance substances,few enzymes and strains can be used for lutein biodegradation.In this study,a lutein degrading strain was isolated from tobacco field soil.It was identified as Enterobacter tabaci strainβ7 by classical morphology and 16S rDNA phylogenetic tree analysis.On the basis of single factor experiments,response surface methodology was designed to optimize the culture conditions for the degradation of lutein by this strainβ7.The results showed that the optimum culture conditions were as follows:sucrose 31.97 g/L,sodium nitrate 3.18 g/L,yeast powder 6.88 g/L and initial pH 6.91.The degradation rate of lutein increased from 85.71%to 93.17%.The results of GC-MS showed that the main degradation products were:β-cyclocitral(0.75%),5,6-epoxy-β-ionone(2.59%),3-hydroxy-β-ionone(1.69%),β-ionone(1.21%),4-hydroxy-β-ionone(0.89%)and Dihydroactinidiolide(1.03%).The research results provide a new strain for lutein degradation and lay a theoretical and application basis for the production of flavoring substances by lutein degradation.