生物洗涤塔内产漆酶苯降解菌的分离鉴定及菌剂制备应用

从生物洗涤塔内循环洗涤液中分离鉴定得到3株苯降解菌Kocuria rosea sp. R(玫瑰色考克氏菌属)、Bacillus sp. W(芽孢杆菌属)，以及Arthrobacter sp. Y(节杆菌属)，通过研究其苯降解动力学，确定苯降解优势菌为Bacillus sp. W，优化其降解条件并探究其代谢途径。结果表明，添加皂角苷可促进苯的生物降解，但根据不同细菌的代谢特点，其影响存在显著差异。在产漆酶菌Bacillus sp. W的降解下，苯的半衰期为8.08 h，而皂角苷与苯共代谢时，苯的半衰期缩短为4.90 h。在最优条件下，即pH为7、起始苯浓度为50 mg·L⁻¹、皂角苷添加量为75 mg·L⁻¹，Bacillus sp. W的漆酶酶活最高为490.21 U·L⁻¹。
在漆酶等参与下苯存在独特苯降解通路，苯在加氧酶作用下转化为邻苯二酚，漆酶可催化酚羟基邻位发生甲氧基取代，进而分子内加成为呋喃衍生物，再经一系列下游酶的作用降解成小分子。在生物反应器中添加由分离得到3株菌株复合而成的菌剂，苯去除效率在第5 d达最高81.21%，比常规驯化活性污泥提前了17 d，还增强了反应器的抗冲击能力。将菌剂接种到实验室的泡沫生物洗涤反应器中，实现了反应器快速启动，启动期仅为5 d。本研究可为生物技术治理疏水性和难降解性VOCs提供参考。

Isolation,identification and preparation of laccase benzene degrading bacteria in biological scrubber tower

Three strains of benzene degrading bacteria, Kocuria rosea sp. R, Bacillus sp. W and Arthrobacter sp. Y were isolated from the circulating scrubbing liquid in a bioscrubber. Bacillus sp. W was identified as the highly efficient strain for benzene-degrading by studying the kinetics of benzene degradation. the degradation conditions of wich were optimized and the metabolic pathways were explored. The results showed that the existence of saponin could promote benzene biodegradation, but the effects were significantly different depending on the metabolic properties of different bacteria. The half-life of benzene was 8.08 h under degradation by laccase producing bacteria Bacillus sp. W, while the half-life of benzene was shortened to 4.
90 h under the cometabolism of saponin and benzene. Bacillus sp. W showed a maximum laccase enzyme activity of 490.21 U·L−1 under optimal conditions with the pH at 7, an initial benzene concentration of 50 mg·L−1 and a saponin addition of 75 mg·L−1 . There was a unique benzene degradation pathway with the participation of laccase. Benzene was converted to catechol by the action of oxygenase, and laccase catalyzed methoxy substitution of phenol hydroxyl ortho positions, and then furan derivatives were generated by intramolecular addition, which were then degraded to small molecules by the action of a series of downstream enzymes. With the addition of microbial agent compounded with 3 strains, the removal efficiency of benzene reached 81.21 % on the fifth day, which was 17 days earlier than the conventional domesticated activated sludge, the shock resistance of the reactor was also enhanced . A rapid reactor start-up with a start-up period of only 5 d was achieved by inoculation of the bacterial agent into the laboratory foam bioscrubber reactor. This study can provide a reference for biotechnological treatment of hydrophobic and non-degradable VOCs.