微小杆菌(Exiguobacterium sp.)对肉桂酸降解行为

Degradation of cinnamic acid by Exiguobacterium sp. strain

摘要:

【目的】为有效缓解自毒物质肉桂酸对西瓜等作物生长的危害，从宁夏中卫硒砂瓜连作土壤中分离筛选得到一株高效降解肉桂酸的菌株，研究其基本降解特性。【方法】分离筛选得到一株能有效利用肉桂酸生长的菌株，采用16S rRNA基因序列分析进行菌株鉴定，运用高效液相色谱法和西瓜幼苗生长毒性实验检测降解特性。【结果】从多年西瓜连作土壤中筛选得到一株高效降解肉桂酸的细菌R30，鉴定为Exiguobacterium sp.，其96 h内对肉桂酸的降解率可达99%以上，最适降解温度和pH分别为30 °C、pH 7.0。除肉桂酸外，该菌也能够高效降解香豆酸、阿魏酸、苯甲酸等其他酚酸类物质，表现出一定的底物广谱性；检测96 h降解液对西瓜种子萌发直至幼苗生长阶段的影响表明，该菌株可有效缓解肉桂酸对西瓜幼苗的生长抑制作用。【结论】菌株R30在肉桂酸、香豆酸、阿魏酸、苯甲酸等酚酸类物质导致的农作物连作障碍治理领域具有潜在的开发应用价值。

Abstract:

[Objective] In order to alleviate the harm of cinnamic acid, an auto-toxic substance to the watermelon and other related crops, a bacterial strain with high efficacy of degradation of cinnamic acid was isolated from soils collected in watermelon field of Zhong-wei county, Ningxia. Its characteristics of cinnamic acid-degradation were evaluated. [Methods] A microbe which could effective use cinnamic acid was isolated. 16S rRNA gene sequence data was used to the strain identification. The degrading kinetics of cinnamic acid by strain R30 was determined by HPLC. A plant growth chamber test was performed to confirm the efficacy of R30 to resume the vitality of watermelon seedlings. [Results] A bacterial strain R30, which was isolated from watermelon continuous cropping soil, was identified as Exiguobacterium sp.. This strain could degrade 99% of cinnamic acid within 96 h at 30 °C, pH 7.0. Strain R30 was also found to degrade coumalic acid, ferulic acid, and benzoic acid efficiently as well as cinnamic acid. Plant growth chamber test indicated that strain R30 could efficiently alleviate the inhibition of cinnamic acid on watermelon seedlings. [Conclusion] The R30 strain possesses the ability of degrading a wide range of phenolic acids, thus has a potent applications in management of crop continuous cropping obstacles which caused by cinnamic acid, coumalic acid, ferulic acid, and benzoic acid.