1,4-二噁烷污染的生物修复效果很大程度上取决于其降解菌的活性和数量.本研究在前期获得1,4-二噁烷高效降解菌Xanthobacter flavus DT8的基础上,研究了该菌的扩大培养方法,并制备了易于贮藏和运输的固态菌剂,考察了菌剂的性能.实验结果表明,菌株X.flavus DT8可在富营养培养基中培养,较优的培养基配方为:Na_2HPO_4·12H_2O 1.0 g·L^(-1),NH_4Cl 1.0 g·L^(-1),MgSO_4·7H_2O 0.2 g·L^(-1),酵母粉5.0 g·L^(-1),蛋白胨1.0g·L^(-1),丙酮酸钠1.0 g·L^(-1),pH 7.0~7.2.X.flavus DT8经发酵罐中扩大培养后,以草炭、硅藻土为载体,经进一步固态发酵制备了固态菌剂,微生物含量为2.17×10^(11)CFU·g^(-1),对1,4-二噁烷的降解效果明显优于活菌液.该菌剂具有良好的贮藏稳定性,4℃保藏90 d后对100 mg·L^(-1)的1,4-二噁烷48 h内去除率为63%;同时具有良好的底物广谱性,对醇类、苯系物和醚类物质也有很好的降解能力.
The efficiency of 1,4-dioxane bioremediation largely depends on the activity and number of its degrader. In this study, the method of enriching the efficient 1,4-dioxane-degrading bacterium, Xanthobacterflavus DT8, was investigated. A solid composite microbial inoculant was prepared based on the 1,4-dioxane degradation performance. Results indicated that X. flavus DT8 could he enriched in nutrient culture medium, with optimal components as follows: Na2HPOa. 12H20 1.0 g.L-l ; NH4C1 1.0 g.L-1 ; MgSO4-7H20 0.2 g.L-1 ; yeast extract 5.0 g.L-1 ; tryptone 1.0 g.L-1 ; sodium pyruvate 1.0 g. L-1 ; pH 7.0 - 7.2. After cultivation in a fermenter, the solid-state fermentation of X. flavus DT8 was carried out to prepare the solid composite microbial inoculant by adding peat and diatomite as carriers. The biomass concentration of this solid inoculant was 2.17×1011 CFU-g-1. After stored at 4℃ for 90 d, the microbial inoeulant could remove 63% of 1,4-dioxane within 48 h when the initial substrate concentration was 100 mg·L-1, showing a highly desirable storage stability. It also exhibited excellent degradation ability to alcohols, BTEX and other ethers.