Isolation of bacteria involved in ammonium uptake to develop a bioformulation for wastewater treatment.

Ammonium contamination in wastewater poses significant threats to aquatic ecosystems and public health. In this study, bacterial strains capable of ammonium uptake were isolated from seafood processing wastewater and evaluated for their potential application in producing bioformulations. From 25 strains isolated, 4 strains demonstrated ammonium removal efficiencies greater than 90% at an initial concentration of 100 ppm. The most efficient strain, WV5.7, achieved ammonium removal rates of 99 and 88.6% at 100 ppm and 200 ppm ammonium, respectively, after 24 hours of cultivation in mineral medium. Based on 16S-rRNA gene sequencing and biochemical characterization, strain WV5.7 was identified as Pseudomonas protegens WV5.7. Suitable conditions for ammonium uptake included aerobic cultivation at pH 7, with the temperature range from 28 oC to 31 oC, and salinity below 1%. Seven carrier materials were applied for storing strain WV5.7, including sugarcane bagasse, sawdust, coconut coir, soybean residue, talc, and mixtures of talc with bagasse or sawdust (1:1, w/w). Among these, talc powder and the sawdust-talc mixture were the most effective carriers, maintaining ammonium uptake activity and viable cell numbers reaching above 106 CFU/g after 180 days of storage. The addition of vitamin B12 to the bacterial suspension did not significantly enhance bacterial viability or activity. Bioformulations retained their ammonium removal capability in both mineral medium and a lab-scale domestic wastewater treatment model. These findings highlighted P. protegens WV5.7 as a promising candidate for the development of microbial products to treat ammonium-rich wastewater. Ammonium contamination in wastewater poses significant threats to aquatic ecosystems and public health. In this study, bacterial strains capable of ammonium uptake were isolated from seafood processing wastewater and evaluated for their potential application in producing bioformulations. From 25 strains isolated, 4 strains demonstrated ammonium removal efficiencies greater than 90% at an initial concentration of 100 ppm. The most efficient strain, WV5.7, achieved ammonium removal rates of 99 and 88.6% at 100 ppm and 200 ppm ammonium, respectively, after 24 hours of cultivation in mineral medium. Based on 16S-rRNA gene sequencing and biochemical characterization, strain WV5.7 was identified as Pseudomonas protegens WV5.7. Suitable conditions for ammonium uptake included aerobic cultivation at pH 7, with the temperature range from 28 oC to 31 oC, and salinity below 1%. Seven carrier materials were applied for storing strain WV5.7, including sugarcane bagasse, sawdust, coconut coir, soybean residue, talc, and mixtures of talc with bagasse or sawdust (1:1, w/w). Among these, talc powder and the sawdust-talc mixture were the most effective carriers, maintaining ammonium uptake activity and viable cell numbers reaching above 106 CFU/g after 180 days of storage. The addition of vitamin B12 to the bacterial suspension did not significantly enhance bacterial viability or activity. Bioformulations retained their ammonium removal capability in both mineral medium and a lab-scale domestic wastewater treatment model. These findings highlighted P. protegens WV5.7 as a promising candidate for the development of microbial products to treat ammonium-rich wastewater.