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.
Quan
Xiangchun
X
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. xchquan@bnu.edu.cn
Tang
Hua
H
Ma
Jingyun
J
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