Establishment of RP-HPLC and SDS-PAGE analytics of an antiseptic peptide to investigate its elimination on a model waste water plant

Abstract

The use of antibiotics in the human health care leads to serious issues. Frequent use and often misuse of antibiotics results in multi - resistant bacteria (Bérdy, 2012). An incomplete degradation of the antibiotics in communal waste water plants supports the development of resistances (Kårelid et al., 2017). Thus, it is not only necessary to establish new ways of waste water purification to eliminate pharmaceutical drugs but as well to find new drugs to overcome the problematic of resistance. A promising approach is the development of peptide drugs. The aim of this study was the characterization of the antiseptic peptide Aspidasept®. For this purpose analytical methods such as the RP-HPLC and the SDS-PAGE were established. Afterwards, the behavior of Aspidasept® on three stages of a lab scale sewage plant was examined to investigate in the purification of local waste water contaminated with pharmaceutical peptides. The adsorption on granulated activated carbon at different conditions, the filtration performance and the behavior on the biological stage were observed. The characterization of the peptide showed the formation of dimers in aqueous solutions. Both established methods were suitable for the analysis and showed equal results. An antimicrobial activity was not observed. The adsorption on granulated activated carbon showed no significant temperature dependent behavior. With increasing activated carbon concentration the adsorption equilibrium decreased. The adsorption behavior can be well described using the Freundlich-Isotherm. For the adsoption in dem. water, the Freundlich parameters K = 0.187 [(μg/gGAC)/(μg/L)]n and n = 0.985 were obtained. For the filtration with a 1000 Da nanofiltration membrane a retention of 100 % were achieved. The filtration results in low recovery rates of the peptide (between 40 % and 85 %). The recovery is depending on the ionic strength and the pH of the solution. The trials in synthetic waste water showed a complete adsorption of the peptide onto the particles of the waste water. A chemical recovery of the peptide from the particles was feasible. The obtained results indicate that the purification of peptide contaminated waste water with the described methods is possible.