Benzoate and salicylate degradation by Halomonas campisalis, an alkaliphilic and moderately halophilic microorganism

Alkaliphiles and halophiles have considerable potential to treat organic pollutants in industrial wastewaters having high pH and salinity. As model aromatic compounds, benzoate and salicylate at concentrations up to 380 mg/L were degraded as carbon and energy sources by Halomonas campisalis, an alkaliphile and moderate halophile. Aerobic batch experiments were performed at 50 and 100 g/L NaCl and pH 9. Detected metabolites, catechol and cis, cis-muconate, indicated that H. campisalis used the ortho degradation pathway for both substrates. For benzoate concentrations up to 1600 mg/L, the intermediate 2-hydroxymuconic semialdehyde (2HMSA), characteristic of the meta pathway, was not detected. Improved understanding and characterization of these degradation processes in high pH, high salt systems may lead to improved application of haloalkaliphiles for industrial wastewater treatment.