海藻酸钠-生物炭联合固定化菌株降解2-羟基-1,4-萘醌

Alginate-biochar joint immobilization strains technique for 2-hydroxy-1,4-naphthoquinone(lawsone) degradation

[目的]采用联合固定化微生物技术对降解菌Pseudomonas taiwanensis LH-3进行固定,以期为稳定高效降解2-羟基-1,4-萘醌提供理论依据。[方法]通过往20 g·L^(-1)海藻酸钠(SA)中添加2.5 g·L^(-1)生物炭(biochar,马尾松树干700℃高温缺氧热解所得),同时以0.2%接种量接入2-羟基-1,4-萘醌降解菌LH-3,制成联合固定化菌(SA+biochar+bacteria),并考察其结构性能;通过与不添加生物炭的海藻酸钠+菌(SA+bacteria)等4种对照处理进行比较,研究联合固定化菌对2-羟基-1,4-萘醌的降解特性;通过与海藻酸钠+菌处理作比较研究联合固定化菌重复利用性能;通过与游离菌作比较,考察不同环境因素对联合固定化菌降解性能的影响以及联合固定化菌在SBR反应器中的连续降解效果。[结果]联合固定化小球的比表面积为22.26 m^2·g^(-1),而不添加生物炭的海藻酸钠+菌小球比表面积为4.02 m^2·g^(-1);联合固定化菌降解过程中可以充分发挥生物炭吸附和微生物降解联动作用;联合固定化菌与游离细菌相比可耐受更高的底物浓度,适应更广的p H值和温度范围,对重金属的耐受性增强并可以多次循环利用;在实验室规模的SBR反应器中,联合固定化菌可在所观测的24个循环内持续稳定地降解2-羟基-1,4-萘醌。[结论]在海藻酸钠+菌小球中添加生物炭增加了小球的比表面积和降解性能,提高了菌株对外界环境变化的耐受性和重复利用效率以及在SBR反应器中的降解稳定性。

[Objectives]Pseudomonas taiwanensis LH-3 was immobilized successfully to degrade lawsone and the possible underlying mechanism was anticipated to be elucidated in this study. [Methods]The strain was immobilized in sodium alginate beads in which biochar（ the masson pine tree trunk were pyrolyzed at 700 ℃） was added to enhance the removal efficiency. The morphological analysis of the joint immobilized beads was conducted. The degradation behavior of the immobilized bacteria was tentatively investigated along with control assays in terms of different environmental conditions. In addition,the reuse ability was comparatively investigated. Finally,the operation performance of sequencing batch reactor（ SBR） with immobilized strain was systematically evaluated. [Results]Brunner-Emmet-Teller（ BET） results showed that the specific surface area of joint immobilization beads and SA＋bacteria beads were22.26 and 4.02 m^2·g^-1,respectively. The adsorption-degradation performance of joint immobilization strains favored the degradation process. The joint immobilized bacteria showed better abilities than free bacteria in adapting to a wide range of temperature,p H,initial concentration of lawsone and heavy metal. Moreover,joint immobilized strains can be successfully reused for more than9 times. In laboratory- scale SBR,the joint immobilized strain can degrade lawsone in a stable way. [Conclusions]Biochar can increase the surface area of sodium alginate beads and enhance the overall degradation efficiency of immobilized strain. Finally,the jointed immobilized beads can adopt to boarder environmental conditions and possess better application capability.