Function analysis of the effective strain Rhodococcus ruber Em1 in wastewater treatment system by quantitative competitive PCR

Abstract:

A quantitative competitive PCR (QC-PCR) system was developed to quantify the number and analyze the function of the Rhodococcus ruber Em1 strain in a wastewater treatment system in Nanchong oil refinery plant. Strain Em1 was able to degrade various kinds of hydrocarbons and aromatic compounds with high efficiency and produce bio-emulsifier, so it was introduced into the waste liquid petroleum-disposing system. The sediment samples were collected from the disposing system in the range of 5 months, and then the numbers of strain Em1 and degrading efficiencies were studied. The results showed that the primers based on 16S rRNA gene sequence of strain Em1 were specific at species level. The PCR products amplified from sediment total DNA with the specific primers were cloned and sequenced, in which 62.2% were the fragments of 16S rRNA gene of strain Em1. Furthermore, the number of Em1 strain ranging from 3.4×10⁵～4.3×10⁸CFU/g in the sediment samples were detected, which indicated that the strain Em1 added into purposely did exist stably and reproduced well in the waste-deposing system during a long period. The high relativity, with relative coefficient R² of 0.89, between Em1 cell number and the amount of COD (Chemical Oxygen Demand) removal proved that the strain Em1 played an important role in this bio-augmentation treatment system.