Quantitative detection of Enterobacter cloacae strain HO-1 in bioreactor for chromate wastewater treatment using polymerase chain reaction (PCR)

A novel method for the detection of specific microbes using the polymerase chain reaction (PCR) technique was developed and applied for the quantitative detection of Enterobacter cloacae strain HO-1 (HO-1, hereafter) in the experimental apparatus used for the treatment of wastewater containing hexavalent chromium (chromate). Note that HO-1 is capable of reducing toxic chromate to trivalent chromium. Based upon the preliminary experiments using pUC18 DNA, conditions giving a constant amplification rate of the targeted DNA with high reliability were determined for the quantitative detection of its initial concentration by the extrapolation. The cell density of HO-1 determined by the PCR technique was compared with the results counted on the selective medium agar plate conventionally used for the counting of HO-1. The procedure proposed here was successfully applied to estimate the cell density of Enterobacter cloacae HO-1 in the bioreactor for the treatment of chromate wastewater.