Cometabolic biodegradation system employed subculturing photosynthetic bacteria: A new degradation pathway of 4-chlorophenol in hypersaline wastewater

Wang, Liang; Hu, Zhong-Ce; Hu, Mian; Zhao, Jun; Zhou, Peijie; Zhang, Yongjie; Zheng, Xin; Zhang, Yifeng; Hu, Zhong‐Ting; Pan, Zhiyan

doi:10.1016/j.biortech.2022.127670

Cited by 7 publications

(1 citation statement)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A study on saline adaption of activated sludge achieved 91% removal rate to 2-chlorophenol under the condition of 8% NaCl (w/v), but the degrader on strain level was not identified [ 9 ]. Another study claimed that the photosynthetic bacteria could degrade 2-chlorophenol with salinity of less than 2.5% NaCl [ 10 ]. Degradation of chlorophenols and their derivatives by microbes shared the same metabolism pathway with phenolic compound, which has been well demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Adaptive laboratory evolution of Rhodococcus rhodochrous DSM6263 for chlorophenol degradation under hypersaline condition

Zheng,

Zhang,

et al. 2023

Microb Cell Fact

View full text Add to dashboard Cite

Background Normally, a salt amount greater than 3.5% (w/v) is defined as hypersaline. Large amounts of hypersaline wastewater containing organic pollutants need to be treated before it can be discharged into the environment. The most critical aspect of the biological treatment of saline wastewater is the inhibitory/toxic effect exerted on bacterial metabolism by high salt concentrations. Although efforts have been dedicated to improving the performance through the use of salt-tolerant or halophilic bacteria, the diversities of the strains and the range of substrate spectrum remain limited, especially in chlorophenol wastewater treatment. Results In this study, a salt-tolerant chlorophenol-degrading strain was generated from Rhodococcus rhodochrous DSM6263, an original aniline degrader, by adaptive laboratory evolution. The evolved strain R. rhodochrous CP-8 could tolerant 8% NaCl with 4-chlorophenol degradation capacity. The synonymous mutation in phosphodiesterase of strain CP-8 may retard the hydrolysis of cyclic adenosine monophosphate (cAMP), which is a key factor reported in the osmoregulation. The experimentally verified up-regulation of intracellular cAMP level in the evolved strain CP-8 contributes to the improvement of growth phenotype under high osmotic condition. Additionally, a point mutant of the catechol 1,2-dioxygenase, CatAN211S, was revealed to show the 1.9-fold increment on activity, which the mechanism was well explained by molecular docking analysis. Conclusions This study developed one chlorophenol-degrading strain with extraordinary capacity of salt tolerance, which showed great application potential in hypersaline chlorophenol wastewater treatment. The synonymous mutation in phosphodiesterase resulted in the change of intracellular cAMP concentration and then increase the osmotic tolerance in the evolved strain. The catechol 1,2-dioxygenase mutant with improved activity also facilitated chlorophenol removal since it is the key enzyme in the degradation pathway.

show abstract

Section: Introductionmentioning

confidence: 99%