Molecular characterization of the nitrifying bacterial consortia employed for the activation of bioreactors used in brackish and marine aquaculture systems

Abstract

a b s t r a c tThe addition of commercial nitrifying bacterial products has resulted in significant improvement of nitrification efficiency in recirculating aquaculture systems (RAS). We developed two nitrifying bacterial consortia (NBC) from marine and brackish water as start up cultures for immobilizing commercialized nitrifying bioreactors for RAS. In the present study, the community compositions of the NBC were analyzed by universal 16S rRNA gene and bacterial amoA gene sequencing and fluorescence in situ hybridization (FISH). This study demonstrated that both the consortia involved autotrophic nitrifiers, denitrifiers as well as heterotrophs. Abundant taxa of the brackish water heterotrophic bacterial isolates were Paenibacillus and Beijerinckia spp. whereas in the marine consortia they were Flavobacterium, Cytophaga and Gramella species. The bacterial amoA clones were clustered together with high similarity to Nitrosomonas sp. and uncultured beta Proteobacteria. FISH analysis detected ammonia oxidizers belonging to b subclass of proteobacteria and Nitrosospira sp. in both the consortia, and Nitrosococcus mobilis lineage only in the brackish water consortium and the halophilic Nitrosomonas sp. only in the marine consortium. However, nitrite oxidizers, Nitrobacter sp. and phylum Nitrospira were detected in both the consortia. The metabolites from nitrifiers might have been used by heterotrophs as carbon and energy sources making the consortia a stable biofilm.

Genetic diversity of nitrate reducing bacteria in marine and brackish water nitrifying bacterial consortia generated for activating nitrifying bioreactors in recirculating aquaculture systems

“…and Pseudomonas sp. reported earlier by Kumar et al (2013) by random cloning and sequencing of 16S rRNA gene from the same NBC could be isolated through this work. Alcanivorax dieselolei was reported from ammonia oxidizing consortia, and the denitrifying property was observed when succinate was used as the sole C source (Nakano, Okunishi, Tanaka & Maeda, 2009).…”

“…Under that circumstance, diversity of nitrate reducers was analysed. However, chemolithotrophic nitrifiers along with heterotrophic aerobic denitrifiers, and heterotrophs as scavengers of extrametabolites could be demonstrated through culture-independent approaches (Kumar et al, 2013).…”

“…Uniformly in all the systems maintained with the reactors NO 3 À -N never used to rise above 8 ppm suggesting efficient nitrate reduction under aerated conditions . Community analysis of the NBC by way of random cloning and sequencing and FISH revealed the presence of autotrophic nitrifiers, denitrifiers and heterotrophs in the consortia (Kumar et al, 2013). In a study of ecophysiological interaction between nitrifying and heterotrophic bacteria in autotrophic nitrifying biofilms, the presence of 50% nitrifying and 50% heterotrophic bacteria has been determined using micro-autoradiography and fluorescent in situ hybridization techniques (MAR-FISH) (Kindaichi, Ito & Okabe, 2004).…”

Bacterial community analysis of marine recirculating aquaculture system bioreactors for complete nitrogen removal established from a commercial inoculum

“…Characterization of the microbial communities in biofilters in RAS is of interest not only because it increases our understanding of the system’s microbial ecology, but also because it may provide the basis for managing such communities (Kumar et al, 2013; Michaud et al, 2014; Rurangwa and Verdegem, 2015), enhancing their function and reliability (Huang et al, 2016). …”

Limonia Acidissima L. (Wood Apple) as Feed Additive Enhanced Growth Performance, Immune Response and Disease Resistance of Indian Major Carp, Catla Catla (Ham.) Against Aeromonas Hydrophila Infection

“…The fish were acclimatized for 10 days in laboratory condition in 1000 L fibre reinforced plastic tanks at 30° ± 2 0 C, under continuous aeration. Ammonia and dissolved oxygen contents were maintained using Stringed Bed Suspended Bioreactor (SBSBR) 36 , a technology commercialized through M/s Oriental Aquamarine Biotech (P) Ltd, Coimbatore, India. The reactors were activated under laboratory conditions and used in the aquaculture system.…”