Metabolic versatility of halotolerant and alkaliphilic strains of Halomonas isolated from alkaline black liquor

Abstract

Wheat straw black liquor is a notorious pulp mill wastewater with very high pH and pollution load. Two halotolerant and alkaliphilic bacteria, designated as Halomonas sp. 19-A and Y2, were isolated from wheat straw black liquor and shown to be able to use guaiacol, vanillin, dibenzo-p-dioxin, biphenyl and fluorene, as sole carbon and carbazole as sole carbon and nitrogen source at pH 9.5 and in the presence of 10% NaCl. The two strains produced carboxymethylcellulase (CMCase), xylanase, lipase, amylase, and pullulanase. High activities of CMCase, xylanase, and amylase were observed at pH 5.0–11.0 and NaCl concentrations of 0–15%. The metabolic versatility of these Halomonas strains even under extreme pH and salinity conditions makes them promising agents for bioremediation and industrial processes.