Interactions between phyllosphere bacteria and urban air pollution
24 January 2018
Stadscampus, Promotiezaal "De Grauwzusters" - Lange Sint-Annastraat 7 - 2000 Antwerpen (route: UAntwerpen, Stadscampus
Organization / co-organization:
Department of Bioscience Engineering
Sarah Lebeer & Siegfried Denys
PhD defence Wenke Smets - Faculty of Science, Department of Bioscience Engineering
Bioremediation is the use of biological entities for the degradation or conversion of pollutants to (more) harmless substances. To date, air pollution is harmful for human health, plants, animals, and buildings, especially in urban areas. This PhD work explored an alternative pollution abatement strategy, the use of bacteria for bioremediation of urban air. First, the bacterial communities in the phyllosphere (leaf surfaces) of urban plants were studied in depth, with a focus on the possible impact of environmental factors such as air pollution and traffic intensity on these communities. Overall, we found rather weak but significant correlations between phyllosphere community composition and indicators for air pollutants, but the main factor for community composition seemed to be the location. The effect of location in an urban environment on the bacterial phyllosphere was related with the density of urban plants nearby, implying interesting interactions between phyllosphere communities of different plants in close proximity to each other.
In addition to these ecological studies, bacterial strains were isolated from both the urban atmosphere and phyllosphere. These bacterial (and archaeal) isolates made up a diverse collection of known and new pollutant-resistant species and strains. Some of these bacterial strains were tested for their biodegradation capacity in a newly designed, in-house-developed platform for testing the biodegradation of gaseous toluene. Finally, the application of different bacterial strains onto leaves led to different results, indicating that, when the application of non-native strains meet certain requirements, they could be successfully introduced in a native phyllosphere community. The results of this PhD work revealed new possibilities for future research, both towards applications of air bioremediation and towards phyllosphere ecology.