Isolation and Characteristics of Novel Calcium Chloride Tolerant Strain and Its Capable of Biodegrading Saline Diosgenin Wastewater

摘要

In the screening for halophilic bacteria capable of biologically degrading refractory organics in saline diosgenin wastewater with high COD concentrations, a novel CaCl2-tolerant bacterial strain V430, was isolated from the activated sludge of the wastewater treatment system of a diosgenin production plant at Shiyan city, Hubei province, central China. Strain V430 was identified as Staphylococcus saprophyticus according to its morphological, physiological and biochemical properties and the analysis of its 16S rDNA gene sequence with 98.0-99.0% similarity to many strains of this species. Detailed studies on biological characteristics and COD removal efficiencies of the strain V430 at different CaCl2 concentration diosgenin wastewater were determined. Growth capability of bacterial strain V430 was obviously stimulated by the addition of bivalent metal ions such as Fe2+，Zn2+，Co 2+ and Ni2+ in optimal concentration value of 200 mg/L, 100 mg/L, 20 mg/L and 10 mg/L, respectively. And, the bacterial strain V430 growth capability was declined with addition of Cu2+, especially the concentration of Cu2+ exceeded 10 mg/L. Adscititious K+ of 200 mg/L could conduce to strain V430’s growth well and intracellular glutamate production in 9.0% CaCl2 stress. Finally, the optimal COD removal efficiency of strain V430 treating diosgenin wastewater was up to 68.7% deduced from orthogonal experiments.