*4.1. Phylogenetic Analysis*

Twenty-four rare actinomycete strains and a marine strain of the phylum *Proteobacteria* (Table S1) were previously isolated and taxonomically identified (through 16S rRNA gene sequencing) from the Antarctic and sub-Arctic sediment core collection from two separate studies in conjunction with the Scottish Association for Marine Sciences [11,12]. These strains were selected based on taxonomy and isolation location. Using the 16S rRNA gene sequences, a maximum likelihood (ML) phylogenetic tree was constructed (Kimura 2-parameter model, 1000 bootstraps) using Mega 7 (v 7.0.26) (https://www. megasoftware.net/ (accessed on 9 November 2020)) [80,81] with visualisation and annotation using FigTree (v 1.4.3) (http://tree.bio.ed.ac.uk/software/figtree (accessed on 9 November 2020)). The GenBank accession numbers for the 16S rRNA gene sequences are the following: MT135519 (KRD153), MT135569 (KRD128), MT135795 (KR077), MT135986 (KRD070), MT136106 (KRD026), MT136242 (KRD012), MT136243 (KRD022), MT136510 (KRD096). The remaining strains were deposited in GenBank as mentioned in [11].
