Bioaugmentation with the nicotine-degrading bacterium Pseudomonas sp. HF-1 in a sequencing batch reactor treating tobacco wastewater: degradation study and analysis of its mechanisms.
The highly effective nicotine-degrading bacterium Pseudomonas sp. HF-1 was augmented in an SBR system that is used to treat tobacco wastewater. Compared to the non-bioaugmented (non-BA) system, the bioaugmented (BA) system exhibited considerably stronger pollution disposal abilities, with 100% nicotine degradation and more than 84% chemical oxygen demand (COD) removal within 12h. Nicotine degradation had a significant effect on COD removal in SBRs (r=0.928, p<0.01). The mechanisms of bioaugmentation were systematically investigated using a combination of polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) and a toxicity assay (protein carbonyl (PC) and DNA-protein crosslinking (DPC)). DGGE fingerprint profiles showed that the number of bands and the Shannon-Wiener index decreased at a nicotine load of 250mg/L compared to a 40-130mg/L nicotine load in the non-BA system. However, a stepwise increase in the Shannon-Wiener index was found during all periods in the BA system. A comparison of sequences excised from DGGE gels demonstrated significant differences in the dominant microbial species between the two SBRs. This result suggested that bioaugmentation of strain HF-1 could select cooperators for treating complicated tobacco wastewater. The PC content and the DPC coefficient increased significantly at levels higher than 80mg/L in the non-BA system; nevertheless, no increase was observed in the BA system during the stepwise nicotine load. This indicated that bioaugmentation of strain HF-1 resulted in the maintenance of high treatment activity by minimizing the nicotine toxicity for other microbes in the BA system. In conclusion, the rapid nicotine degradation of strain HF-1 performed a vital function in SBR by influencing the microbial community structure, dynamics and activity of the activated sludge system.
Wang
Meizhen
M
College of Life Sciences, Zhejiang University, Hangzhou 310058, China. wangmeizhenyiyun@163.com
Yang
Guiqin
G
Min
Hang
H
Lv
Zhenmei
Z
Jia
Xiuying
X
D001483:Base Sequence; D019149:Bioreactors; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D007220:Industrial Waste; D009538:Nicotine / Q000378:metabolism*; D011549:Pseudomonas / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D017931:DNA Primers; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D009538:Nicotine