Organic pollutants biodegradation by halophile-isolated bacteria in saline conditions

摘要

The present study surveys halophilic bacteria that were isolated from various Tunisian biotopes such as saline, lagoon, fish farm, for their acclimation capacity in fish processing wastewater at 10% NaCl. Hydrolase activities such as protease and lipase were screened. Strains S6 and S10, isolated from fish farm in a lagoon area and showed a protease activity of 503 and 328 U/L in liquid media, were selected. These strains were identified as Salinivibrio genus and more precisely to the species Salinivibrio siamensis and Salinivibrio costicola subsp. alcaliphilus using 16S RNA gene sequencing analysis. Bioremediation of fish processing wastewater was investigated by the use of the selected strains, the species Salinivibrio siamensis and Salinivibrio costicola subsp. alcaliphilus in comparison with urban activated sludge. The experiments were performed at different salt concentrations (10-20%). As salinity increased, the TOC removal efficiency was decreasing, and then increasing progressively through time. The Total Organic carbon (TOC) removal decreased from 22% to 1% when the salinity increased from 100 g.L-1 to 200 g.L-1 NaCl after 24 h of incubation and reached 57% and 7%, respectively after 120 h of incubation. Meanwhile, no TOC removal was obtained with the use of urban activated sludge.