2.2.1. Bacteria

To date, 78 genera belonging to 47 families in four phyla have been cultured from sea cucumbers (Table 2) [4,6,17–19,23–26,30–34]. The phylum Proteobacteria was represented by 34 genera, 23 genera belong to the phylum Actinobacteria, 13 genera belong to the phylum Firmicutes, and only eight genera were from the phylum Bacteroidetes. The bacteria isolated from sea cucumbers are mainly the genus *Bacillus*, followed by *Vibrio*, and *Pseudoalteromona* (Table S1).

Bacteria have been isolated from seven species in three genera of sea cucumbers: *Apostichopus japonicus*, *Holothuria atra*, Holothuria edulis, *Holothuria leucospilota*, *Stichopus badionotus*, *Stichopus chloronotus*, and *Stichopus vastus* [4,6,17–19,23–26,30–34]. A. japonicus displayed a high bacterial diversity, and 54 bacterial genera were isolated from this species. Thirty-six genera were isolated from *H. leucospilota*, and fifteen genera were isolated from *S. vastus*. Two, one, six, and three genera of bacteria were isolated from *H. atra*, *H. edulis*, *S. badionotus*, and *S. chloronotus*, respectively (Table 1 and Table S1).
