Butyric Acid- and Dimethyl Disulfide-Assimilating Microorganisms in a Biofilter Treating Air Emissions from a Livestock Facility

Abstract

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 highresolution identification and quantitative assessments of odor-eliminating Actinobacteria-dominated populations of these biofilter environments.

The development of free amino acids and volatile compounds in cheese ‘Oloumoucké tvarůžky’ (PGI) during ripening

“…According to Kristiansen et al . () and Fox et al . (), some microorganisms occurring in smear cheese (such as Flavobacteria spp., Microbacterium spp., Bacillus spp., Actinobacteria spp, etc.)…”

“…As it follows from the following text, this is a general problem concerning most of the metabolites detected. According to Kristiansen et al (2011) andFox et al (2004), some microorganisms occurring in smear cheese (such as Flavobacteria spp., Microbacterium spp., Bacillus spp., Actinobacteria spp, etc.) possess metabolic pathways allowing assimilating of DMDS.…”

Identification of triclosan-degrading bacteria using stable isotope probing, fluorescence in situ hybridization and microautoradiography

“…For all experiments, nitrate mineral salts medium (NMS) was used as carbon-free medium (Whittenbury et al, 1970). All other reagents used for SIP and MAR were commercial products of highest grade (Chen et al, 2011;Kristiansen et al, 2011a;Neufeld et al, 2007).…”

“…DGGE was performed as described in detail elsewhere (Kristiansen et al, 2011a). From DGGE results, distinct DNA bands from the labelled heavy fractions (buoyant density 1.83 and 1.79 g ml 21 ) were chosen for subsequent sequencing (Fig.…”

“…A 16S rRNA clone library was prepared from the high density fractions (1.76-1.80 g ml 21 ) of the SIP incubation with the 13 C-labelled triclosan. The clone library preparation and the phylogenetic analysis were performed as described by Kristiansen et al (2011a) except that the alignment and phylogenetic tree construction were done using MEGA 5 (Tamura et al, 2011). Screening of the clone sequences with Bellerophon v3 (DeSantis et al, 2006) did not identify any putative chimeras.…”