Link between spatial structure of microbial communities and degradation of a complex mixture of volatile organic compounds in peat biofilters

Abstract

Aims: To investigate the relationships between the operation of the volatile organic compound (VOC) removal biofilter and the structure of microbial communities, and to study the impact on degradation activities and the structuring of microbial communities of biofilter malfunctions related to the qualitative composition of the polluted air. Methods and Results: A microbiological study and a measurement of biodegradation activities were simultaneously carried out on two identical peat-packed columns, seeded with two different inocula, treating polluted air containing 11 VOCs. For both reactors, the spatial structure of the microbial communities was investigated by means of single-strand conformation polymorphism (SSCP) analysis. For both reactors, stratification of degradation activities in function of depth was observed. Oxygenated compounds were removed at the top of the column and aromatics at the bottom. Comparison of SSCP patterns clearly showed a shift in community structure in function of depth inside both biofilters. This distribution of biodegradation activities correlates with the spatialization of microbial density and diversity. Although the operating conditions of both reactors were identical and the biodegradation activities similar, the composition of microflora differed for biofilters A and B. Subdivision of biofilter B into two independent parts supplied with polluted air containing the complex VOC mixture showed that the microflora having colonized the bottom of biofilter B retained their potential for degrading oxygenated compounds. Conclusions: This work highlights the spatialization of biodegradation functions in a biofilter treating a complex mixture of VOCs. This distribution of biodegradation activities correlates with the spatialization of microbial density and diversity. Significance and Impact of the Study: This vertical structure of microbial communities must be taken into consideration when dealing with the malfunctioning of bioreactors. These results are also useful information about changes in microbial communities following natural or anthropogenic alterations in different ecosystems (soils and sediments) where structuring of microbial communities according to depth has been observed.

Comparison of Different Packing Materials for the Biofiltration of Air Toxics

“…A plausible explanation is that the CBP biofilter developed a different consortium of microorganisms, which was able to degrade toluene faster than the populations in the other reactors. This is consistent with the observations of Li and Moe, 21 who found differences in DGGE band patterns along the axial direction and between reactors depending on their operating modes, as well as those of Khammar et al, 22 who used single-strand conformation polymorphism analyses and found that different communities developed in two parallel biofilters. They further showed that the distribution of the biodegradation activity correlated with the local microbial density and diversity.…”

Comparison of Microbial Consortia in Refuse-Derived Fuel (RDF) Preparations between Japan and Germany

“…The BOD value of German RDF pellets was lower than that of Japanese RDF pellets, although the plastic content in the former was lower than that in the latter, indicating that the German RDF pellets contained lower amounts of organic materials easily consumed by microorganisms. 7) It is likely that the biodegradation process in the German plant reduced the amounts of fermentable organic materials. The water content of both RDF pellet sample types was low, and the strength of the German RDF pellets was higher than that of the Japanese ones.…”

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

“…In general, Actinobacteria are often found to be a quantitatively important part of the microbial community in biofilters treating VOC (15) and were also found to constitute up to 16% of the total community in a similar air filter treating exhaust air from a pig farm (26). The aerobic Gordonia and Rhodococcus have previously been detected by cultivation in biofilter communities (23), and several other genera of Actinobacteria such as Dietzia, Gordonia, Janibacter, and Rhodococcus are known to oxidize butyric acid as detected in pure culture studies (4,7), but the ability has not yet been shown with in situ experiments. Furthermore, Gordonia has previously been associated with the degradation of hexane using stable isotope-based phospholipid fatty acid analysis on a biofilter treating air from an oil mill (13), which could suggest a more general role for species of this genus.…”