Isolation of marine bacteria through a “bait” approach

There is a great divide between the microbes active in natural environments and the organisms that may be grown in a laboratory setting. In this work we set out to cultivate representatives of the marine myxobacterial clade, a highly diverse, largely uncultured group of Gram-negative bacteria believed to have extensive biosynthetic potential. Sediment samples were collected from the St. Lawrence Estuary and Gulf and the presence of active marine myxobacteria was established through qPCR analysis of 16S rRNA gene and transcript abundances. In the expectation that the marine myxobacteria would exhibit predatory behaviour like their terrestrial counterparts, the sediment samples were then streaked on agar plates that contained common marine bacteria as the sole carbon source. Unexpectedly, in place of myxobacteria we isolated <i>Pseudomonas</i>, <i>Bacillus</i>, and <i>Stenotropomonas</i> spp., among others, revealing a generalized ability for these strains to break down living organic matter and suggesting that "bait" bacteria may be an effective approach for the cultivation of novel marine saprophytes.