Structural and functional responses of sewage microbial communities used for the treatment of a complex mixture of volatile organic compounds (VOCs)

The aim of this work was to assess the impact of the applied mass loading on the selection of an efficient microbial community able to degrade a complex mixture of volatile organic compounds (VOCs). Two reactors were used and were supplied with a gaseous effluent containing 11 VOCs with different concentrations. The response of the microflora was monitored as a function of time: biodegradation activity, bacterial density and diversity. The results showed that the applied mass loading seems to have an impact on the functioning and the genetic structure of the bacterial community. A high mass loading seems to induce a low efficient functioning in terms of elimination efficiency and a simplification of the genetic structure of the total bacterial community with the apparition of a dominant microflora. A low mass loading seems to favour a better functioning and allows to keep a healthier bacterial diversity. In the treatment processes of gaseous effluents, it would be judicious to define the functioning parameters of the process to keep the diversity of important functional bacterial groups. These results provide also useful information about changes in microbial communities following natural or anthropogenic alterations in different ecosystems.