甲硫醇降解菌群筛选及其降解特性研究

Enrichment and characterization of a methanthiol-degradating mixed microbial consortium

从处理甲硫醚(DMS)和丙硫醇(PT)混合废气的生物滴滤塔中富集出一组能够有效降解甲硫醇(MT)的混合菌群,并对其特性进行了系列研究.结果表明,该混合菌群能有效降解MT,菌群较为适宜的生长和降解条件为30℃、p H=7.0,在该条件下能将初始浓度为20 mg·L^(-1)的MT在70 h内降解完全.添加酵母膏(YE)后,MT降解速率进一步提高,降解所需时间缩短10 h.利用高通量测序技术分析混合菌群的群落结构,发现其中优势菌属为Pseudomonas sp.、Thiobacillus sp.和Acinetobacter sp.,所占比例分别为33.78%、21.91%和17.01%.中间产物检测结果表明,混合菌群降解MT的过程中产生了甲醛、H_2S、二甲基二硫醚(DMDS)等物质,推断MT的降解途径可能有如下2条:(1)MT在MT氧化酶作用下形成甲醛和H2S,随后氧化为SO_4^(2-);(2)MT依次转化为DMDS、DMS、二甲基亚砜(DMSO)和二甲基砜(DMSO_2),最后经甲基磺酸(MSA)可生成SO_4^(2-).

A mixed microbial consortium which could utilize methanthiol（ MT） as sole carbon and sulfur source was enriched from biofilm of a biotrickling filter treating dimethyl sulfide（ DMS） and 1-propanethiol（ PT）. Experimental results show that the mixed microbial consortium achieved a high degradation rate of MT. Under the optimized conditions under p H = 7.0 and the operation temperature of 30 ℃,20 mg·L^（-1）of MT could be completely degraded within 70 hours. Moreover,the addition of the yeast extract（ YE） significantly enhanced MT degradation,with shorter time（ 60 hours） for complete degradation. High-throughput sequencing were used to identify the community structure of the mixed microbial consortium. The results indicate that Pseudomonas sp.（ 33. 78%）,Thiobacillus sp.（ 21. 91%）,and Acinetobacter sp.（ 17. 01%） were the dominating bacteria. Furthermore,the intermediates of MT degradation were detected by using GC,GC-MS,and HPLC. Based on the intermediates and the final products,two metabolic pathway of MT were inferred,（1）MT was firstly converted to formaldehyde and H_2S and finally oxidized to sulfate,（2）MT oxidation to sulfate occurs via successive intermediates of DMDS,DMS,DMSO and DMSO_2.