Abundance, diversity and seasonal dynamics of predatory bacteria in aquaculture zero discharge systems

Abstract

Standard aquaculture generates large-scale pollution and strains water resources. In aquaculture using zero discharge systems (ZDS), highly efficient fish growth and water recycling are combined. The wastewater stream is directed through compartments in which beneficial microbial activities induced by creating suitable environmental conditions remove biological and chemical pollutants, alleviating both problems. Bacterial predators, preying on bacterial populations in the ZDS, may affect their diversity, composition and functional redundancy, yet in-depth understanding of this phenomenon is lacking. The dynamics of populations belonging to the obligate predators Bdellovibrio and like organisms (BALOs) were analyzed in freshwater and saline ZDS over a 7-month period using QPCR targeting the Bdellovibrionaceae, and the Bacteriovorax and Bacteriolyticum genera in the Bacteriovoracaeae. Both families co-existed in ZDS compartments, constituting 0.13-1.4% of total Bacteria. Relative predator abundance varied according to the environmental conditions prevailing in different compartments, most notably salinity. Strikingly, the Bdellovibrionaceae, hitherto only retrieved from freshwater and soil, also populated the saline system. In addition to the detected BALOs, other potential predators were highly abundant, especially from the Myxococcales. Among the general bacterial population, Flavobacteria, Bacteroidetes, Fusobacteriaceae and unclassified Bacteria dominated a well mixed but seasonally fluctuating diverse community of up to 238 operational taxonomic units, as revealed by 16S rRNA gene sequencing.

Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment

“…We found indications for cellular recycling caused by the predatory Bacteriovoracaceae (cf. [58]), which was one of the structuring bacterial lineages identified in Additional file 4. Another potential mechanism—one that may be the most important in the depauperate horizon—is differential cell replication.…”

Rebuilding the Gut Microbiota Ecosystem

“…Although predatory bacteria play a relevant role by controlling and affecting bacterial populations in a wide range of environments, and despite the fact that they are known to be almost ubiquitous, only a minority of these bacteria have been studied in some detail for their potential applications [182,183,184,185,186,187]. …”

Biological denitrification using poly(butylene succinate) as carbon source and biofilm carrier for recirculating aquaculture system effluent treatment

“…In addition, Bdellovibrio, a predatory bacterium which attacks and consumes other bacterial strains, was detected with an extraordinary increase during stage V in reactor I. Thus, it can act as an potential antibiotic to control pathogenic bacteria in the aquatic system (Kandel et al, 2014). As for reactor II, Azoarcus was found dominant during the whole operational stage, which might be the main reason for high effluent DOC concentration and stable nitrate removal efficiency, as it has cooperative ability of denitrification and degradation (Horiba et al, 2005).…”