Characterization of the gut bacterial community of the Japanese sea cucumber Apostichopus japonicus

Comparative analysis of the composition and abundance of the gut bacterial community of the Japanese sea cucumber (trepang) Apostichopus japonicus and the sediment from its habitat was carried out. In spite of the presence of strictly aerobic bacteria in the sediments, gut microbiota of this holothurian was shown to be formed by facultative anaerobes from the environment. Irrespective of the geographical location of the habitat, the sea cucumber gut community had a constant composition, considered its normal microflora. Capacity of bacteria isolated from the Japanese sea cucumber for decomposition of starch, sodium alginate, chitin, chondroitin sulfate, Tweens, olive oil, casein, and gelatin was studied. Various degrees of enzymatic activity were shown for 33% of the studied bacterial strains, which indicates a considerable role of the trepang gut microflora in processing and assimilation of organic matter arriving with food.