Isolation of the salt-tolerant bacterium Halomonas sp.A20 and its degradation of saccharin sodium wastewater

Abstract:

[Background] Saccharin sodium wastewater,one type of organic industrial wastewater with high salt,is difficult to be treated.[Objective] To improve the biodegradation of this wastewater,it is in urgent need to study the characteristics of the saccharin sodium wastewater degrading bacteria.[Methods] A bacterial strain A20 capable of degrading saccharin sodium wastewater was isolated by pure culture technology from the activated sludge in the multistage biological contact oxidation system.It was identified based on morphological characteristics,physiological and biochemical properties,and 16s rRNA gene sequence analysis.The optimum conditions for strain A20 to degrade saccharin sodium wastewater were investigated by single factor experiment and response surface method.[Results] The strain A20 belonged to Halomonas.When the salinity of saccharin sodium wastewater in 5%,pH 8.0,and the temperature of 30℃,inoculum ratio at 15%,the chemical oxygen demand (CODcr) removal efficiency was more than 60%.Through the optimization with response surface method,the optimum conditions for Halomonas sp.A20 to degrade the saccharin sodium wastewater:pH 8.0,temperature of 30.3℃,and inoculum ratio of 14.1%.Under this optimum condition,the CODcr removal efficiency was 65.4%.[Conclusion] The salt-tolerant strain A20 obtained in this study can efficiently degrade the organic matter in saccharin sodium wastewater,which can provide excellent microbial strain resources for the treatment of high-salt and high-concentration saccharin sodium wastewater.

Key words:saccharin sodium wastewater;salinity;degrading bacteria;degradation characteristics;strain resources