Microbial Diversity of Biological Filters in Recirculating Aquaculture Systems for Sand Lobster ( Panulirus homarus) Rearing

Abstract

The recirculating aquaculture system (RAS) is a technology that reuses water (often less than 5%) in land-based production for farming aquatic organisms' water treatment. This technology uses filters, either mechanical or biological, for any aquaculture species rearing. In lobster rearing using RAS, one of the most important factors is the quality of rearing water, which depends primarily on the biochemical activities of the microbial communities in the biofilter. There is a significant correlation between the abundance of nitrifying microbial communities and high total ammonia nitrogen (TAN) removal rate. These organisms can convert ammonia accumulates in the system into nitrate. The application of molecular tools (Metagenome 16S Full-Length Barcoding using Oxford Nanopore Platform) to characterize microbial community diversity has been conducted for this study. The diversity of microbes in RAS biofilter for sand lobster rearing is summarized as follows: Nitrification Bacteria group (β-Proteobacteria, g-Proteobacteria, Nitrospirae); Denitrification/Nitrate Reducing Bacteria (α-Proteobacteria, δ-Proteobacteria, Bacteroidetes/Chlorobi, Firmicutes), Sulfide Oxidation Bacteria (ϵ-Proteobacteria), Probiotic Bacteria (Bacillus subtilis, Pseudomonas sp., Roseobacter sp.). This study's results indicate a potential for RAS in sand lobster-intensive aquaculture applications and also discuss future studies' directions.