With the objective to remove dissolved methane from effluents of anaerobic bioreactors, we ecologically engineered non-methanotrophic photogranules to perform methane oxidation. The resulting methanotrophic photogranules stably removed dissolved CH4 in a lab-scale photobioreactor at more than 80%, only using photosynthetically in-situ produced oxygen. We followed reactor performance over time and analysed changes in the microbial community using high throughput sequencing. Individual photogranules differed substantially in their composition and specific CH4 removal rates. Thus, the scale of individual photogranules needs to be considered when, e.g., modelling overall reactor performance. This abstract is based on Safitri et al. (2021).