Removal of tetracycline by aerobic granular sludge from marine aquaculture wastewater: A molecular dynamics investigation

Although biological treatment of marine aquaculture wastewater is promising, the fundamental principles driving the adsorption of tetracycline to microbial cell membrane are not well understood. Using a combination of experiments and molecular dynamics (MD) simulations, the mechanism underlying the biological removal of tetracycline from seawater was investigated. More than 90% tetracycline removal was achieved in an aerobic granular sludge system, with degradation accounting for 30% of total removal. A model of the tetracyclinedipalmitoylphosphatidylcholine lipid bilayers was established to elucidate the transport mechanism of tetracycline from bulk solution to microorganisms' cell membrane. 62% of the driving force for tetracycline adsorption on the cell membrane originated from electrostatic attraction. The electrophilic groups on tetracycline (amino and aromatic groups) were attracted to the phosphate groups in the cell membrane. Sodium ions, which are abundant in seawater, decreased the interaction energy between tetracycline and the cell membrane.

Automated summary

The mechanism of biological removal of tetracycline from marine aquaculture wastewater was investigated using experiments and molecular dynamics simulations. It was found that electrostatic attraction played a significant role in tetracycline adsorption on microbial cell membrane. The presence of sodium ions in seawater decreased the interaction between tetracycline and the cell membrane.