Short Report

Long-term surveillance of sulfate-reducing bacteria in highly saline industrial wastewater evaporation ponds

Eitan Ben-Dov^1,2 , Ariel Kushmaro^1,3 and Asher Brenner⁴

¹  Department of Biotechnology Engineering, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva, 84105, Israel

²  Achva Academic College, MP Shikmim, 79800, Israel

³  National Institute for Biotechnology of the Negev, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel

⁴  Unit of Environmental Engineering, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva, 84105, Israel

author email corresponding author email

Saline Systems 2009, 5:2doi:10.1186/1746-1448-5-2

Published:	18 February 2009

Abstract

Abundance and seasonal dynamics of sulfate-reducing bacteria (SRB), in general, and of extreme halophilic SRB (belonging to Desulfocella halophila) in particular, were examined in highly saline industrial wastewater evaporation ponds over a forty one month period. Industrial wastewater was sampled and the presence of SRB was determined by quantitative real-time PCR (qPCR) with a set of primers designed to amplify the dissimilatory sulfite reductase (dsrA) gene. SRB displayed higher abundance during the summer (10⁶–10⁸ targets ml^-1) and lower abundance from the autumn-spring (10³–10⁵ targets ml^-1). However, addition of concentrated dissolved organic matter into the evaporation ponds during winter immediately resulted in a proliferation of SRB, despite the lower wastewater temperature (12–14°C). These results indicate that the qPCR approach can be used for rapid measurement of SRB to provide valuable information about the abundance of SRB in harsh environments, such as highly saline industrial wastewaters. Low level of H₂S has been maintained over five years, which indicates a possible inhibition of SRB activity, following artificial salination (≈16% w/v of NaCl) of wastewater evaporation ponds, despite SRB reproduction being detected by qPCR.