Although isoprene is emitted from the biosphere in amounts similar to methane, we know very little of its biodegradation. This project aims to investigate bacteria responsible for isoprene biodegradation using both cultivation-dependent and cultivation-independent methods. We are sequencing the genomes of isoprene-utilizing isolates and carrying out comparative genomics in order to advance our understanding of their physiology, biochemistry and molecular biology. In parallel, we are using cultivation-independent methods, including DNA-stable isotope probing (DNA-SIP), using labelled isoprene, to retrieve sequence data of active organisms that may be resistant to laboratory cultivation. Labelled DNA from DNA-SIP experiments is used for amplicon sequencing of 16S rRNA and metabolically functional genes, which provides phylogenetic information on active isoprene degraders. In addition, metagenome sequencing of labelled DNA and genome assembly and reconstruction allows us to identify novel genes or pathways used by isoprene degraders.