Effects of gene augmentation on the removal of 2,4-dichlorophenoxyacetic acid in a biofilm reactor under different scales and substrate conditions.
With a conjugative plasmid pJP4 carrying strain as the donor, two bioaugmentation experiments were conducted in a microcosm biofilm reactor with 2,4-D as the sole carbon source operated in fed-batch mode, and an enlarged lab-scale sequence batch biofilm reactor with mixed carbon sources of 2,4-D and other easily biodegradable compounds, respectively. In the microcosm study under sole carbon source condition, bioaugmentation led to a persistently increased 2,4-D degradation rate in the five operation cycles with enhancement of 13-64%. For the enlarged lab-scale bioaugmentation experiment under mixed carbon source conditions, no enhancement in 2,4-D removal could be observed during start-up period. After a period of operation, biofilm samples from the bioaugmented reactor demonstrated a stronger degradation capacity than the control and showed the presence of a large number of transconjugants. This study indicates that bioaugmentation based on plasmid horizontal transfer is a feasible strategy to establish functional microbial community in a biofilm reactor, and the strong selective pressure of 2,4-D existing alone and persistently was more favorable for the success of gene augmentation.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. xchquan@bnu.edu.cn
Xiangchun
X
Quan
Hua
H
Tang
Jingyun
J
Ma
D015084:2,4-Dichlorophenoxyacetic Acid / Q000302:isolation & purification*; D018441:Biofilms; D019149:Bioreactors; D004587:Electrophoresis, Agar Gel; D005798:Genes, Bacterial; D018613:Microscopy, Confocal; D010957:Plasmids; D016133:Polymerase Chain Reaction; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism*
D015084:2,4-Dichlorophenoxyacetic Acid