Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark.
Appl Environ Microbiol. 2011 Dec;77(24):8595-604. doi: 10.1128/AEM.06175-11. Epub 2011 Oct 14.
Biofiltration has proven an efficient tool for the elimination of volatile organic compounds (VOCs) and ammonia from livestock facilities, thereby reducing nuisance odors and ammonia emissions to the local environment. The active microbial communities comprising these filter biofilms have not been well characterized. In this study, a trickle biofilter treating air from a pig facility was investigated and proved efficient in removing carboxylic acids (>70% reduction), mainly attributed to the primary filter section within which reduced organic sulfur compounds were also depleted (up to 50%). The secondary filter eliminated several aromatic compounds: phenol (81%), p-cresol (89%), 4-ethylphenol (68%), indole (48%), and skatole (69%). The active butyric acid degrading bacterial community of an air filter sample was identified by DNA stable-isotope probing (DNA-SIP) and microautoradiography, combined with fluorescence in situ hybridization (MAR-FISH). The predominant 16S rRNA gene sequences from a clone library derived from "heavy" DNA from [(13)C(4)]butyric acid incubations were Microbacterium, Gordonia, Dietzia, Rhodococcus, Propionibacterium, and Janibacter, all from the Actinobacteria. Actinobacteria were confirmed and quantified by MAR-FISH as being the major bacterial phylum assimilating butyric acid along with several Burkholderiales-related Betaproteobacteria. The active bacterial community assimilating dimethyl disulfide (DMDS) was characterized by DNA-SIP and MAR-FISH and found to be associated with the Actinobacteria, along with a few representatives of Flavobacteria and Sphingobacteria. Interestingly, ammonia-oxidizing Betaproteobacteria were also implicated in DMDS degradation, as were fungi. Thus, multiple isotope-based methods provided complementary data, enabling high-resolution identification and quantitative assessments of odor-eliminating Actinobacteria-dominated populations of these biofilter environments.
生物过滤已被证明是从畜牧设施中去除挥发性有机化合物 (VOC) 和氨的有效工具，从而减少了对当地环境的恶臭和氨排放。这些过滤生物膜中包含的活性微生物群落尚未得到很好的描述。在这项研究中，研究了处理来自猪圈设施空气的滴滤生物过滤器，结果证明其对去除羧酸（>70%的减少率）非常有效，这主要归因于主要过滤器部分，其中还原有机硫化合物也被耗尽（最多 50%）。二级过滤器消除了几种芳香族化合物：苯酚（81%）、对甲酚（89%）、4-乙基苯酚（68%）、吲哚（48%）和粪臭素（69%）。通过 DNA 稳定同位素探针（DNA-SIP）和微放射性自显影与荧光原位杂交（MAR-FISH）相结合，鉴定了空气过滤器样品中活性丁酸降解细菌群落。从 [13C4]丁酸孵育的“重”DNA 衍生的克隆文库中获得的主要 16S rRNA 基因序列来自微杆菌属、戈登氏菌属、迪茨氏菌属、红球菌属、丙酸杆菌属和詹尼氏菌属，均来自放线菌。放线菌通过 MAR-FISH 得到证实和量化，是沿用到丁酸的主要细菌门，还有一些与伯克霍尔德氏菌相关的β变形菌。通过 DNA-SIP 和 MAR-FISH 对主动二甲基二硫醚 (DMDS) 同化细菌群落进行了表征，发现其与放线菌有关，还有一些黄杆菌和鞘脂单胞菌的代表。有趣的是，氨氧化β变形菌也参与了 DMDS 的降解，真菌也是如此。因此，多种基于同位素的方法提供了互补的数据，使我们能够对这些生物过滤器环境中消除气味的占主导地位的放线菌种群进行高分辨率的识别和定量评估。
