Ramya R Nair
Cochin University of Science and Technology, India
Title: Ammonia oxidizing bacteria and archaea in zero water exchange shrimp culture systems managed with bioremediation based on functional gene amoA analyses
Biography
Biography: Ramya R Nair
Abstract
Zero water exchange shrimp culture systems have emerged as the best option to address the demands of bio-security and environmental sustainability in the global aquaculture industry. In zero water exchange shrimp culture systems managed by the application of the indigenous Bacillus cereus sensu lato MCCB 101 (Genbank Acc. No. EF 062509) containing preparation ‘Detrodigest’ for the bioremediation of detritus, the environmental qualities were found to be stable throughout the culture period. Moreover, the ammonia, nitrite and nitrate were at negligible levels indicating the presence of stable and active nitrifying microbial communities. In present study, the diversity and community variation in bacterial and archaeal ammonia oxidizers in these systems were analyzed using amoA-the catalytic subunit of the functional gene ammonia mono oxygenese. The sediment samples were collected from three different culture ponds during different culture phases and the meta-genomic DNA were isolated. The bacterial and archaeal amoA genes were amplified from the meta-genome using specific primers, amoA gene libraries were constructed and selected positive clones were sequenced and analyzed. The phylogenetic analyses of bacterial amoA genes showed maximum similarity to that of uncultured Nitrosomonas species whereas the archaeal amoA genes showed similarity to that of Crenarchaeota. The diversity analyses of bacterial and archaeal amoA genes showed more diversity for archaeal amoA genes especially towards the end of culture. The ecological roles of bacteria and archaea in nitrogen biogeochemical cycling and bioremediation in these systems need to be further analyzed by their abundance in relation to substrate availability