Ecological functions and environmental fate of exopolymers of Acidobacteria

Costa, O.Y.A. (2020)

Doctoral Thesis

Acidobacteria is a widely distributed phylum but their functional roles in ecosystem processes are still largely elusive. The Granulicella genus belongs to the class Acidobacteriia and is known to produce copious amount of Extracellular Polymeric Substances (EPS), which are fundamental for microbial life. The major goal of my thesis was to investigate and understand the metabolism of Granulicella sp. strains WH15 and 5B5, and the functions and environmental fate of EPS of Granulicella sp. WH15 (WH15EPS). Optimization of carbon concentration and manganese in culture medium allowed our strains, especially WH15, to grow faster in laboratory conditions, producing extractable amounts of EPS. Using the Stable Isotope Probing technique, we observed the incorporation of WH15EPS by Singulisphaera and its connections to other Planctomycetes and Acidobacteria, which were not reported before. In addition, our results showed, in the genomes of the microbes which incorporated WH15EPS, a large diversity of glycoside hydrolase with biotechnological potential and a high number of unclassified microorganisms that could be targeted for future studies. The data presented in this thesis establish a solid fundamental basis for more mechanistic studies of Acidobacteria and other uncultivated microbes.

• Acidobacteria
• Granulicella
• Stable Isotope Probing
• EPS
• Planctomycetes
• Metagenomics
• Microbial Community

• All authors: Costa, O.Y.A.
• Supervisor: Raaijmakers, J.M.
• Co-supervisor: Kuramae, E.E.
• Committee: Wezel, G.P. van; Klinkhamer, P.G.L.; Bezemer, T.M.; Hefting, M.M.; Kowalchuk, G.A.; Faust, K.
• Qualification: Doctor (dr.)
• Awarding Institution: Institute of Biology, Faculty of Science, Leiden University
• Date: 2020-07-09
• ISBN (print): 9789463326353
• Sponsorship: CNPq, CAPES/NIOO-KNAW