Analytical study of effective biodegradation of p-cresol using Serratia marcescens ABHI001: application in bioremediation

Abstract

This study evaluated the capability of Serratia marcescens ABHI001 to effectively degrade p-cresol through different techniques. The molecular identity of the laboratory isolate S. marcescens ABHI001 was confirmed through the 16S ribosomal DNA gene pattern, and its morphological features were investigated through field-emission scanning electron microscopy. In addition, the degradation behavior of the isolate for cresol was verified using several techniques, including UV-visible spectroscopy, followed by high-performance liquid chromatography (HPLC), gas chromatography, and Fourier transform infrared spectroscopy. The maximum degradation percentage of 85% for p-cresol could be achieved after 18 h of incubation with S. marcescens ABHI001. The formation of p-hydroxybenzaldehyde, p-hydroxybenzoate, and protocatechuate metabolites was confirmed through HPLC. The study results indicate that S. marcescens ABHI001 may have applications in the bioremediation of organic pollutants, such as p-cresol.

Keywords: Biodegradation; Organic pollutants; Serratia marcescens; p-Cresol.

Fig. 1

Phylogenetic tree neighbor-joining based on 16S rDNA gene sequence showing the relationship between bacterial strain Serratia marcescens ABHI001 and other relatives within genus

Fig. 2

Percentage of p-cresol degradation by isolated bacterial strains named as ABHI001, ABHI002, ABHI003, ABHI004, and ABHI005. Initial conditions: concentration of p-cresol = 0.003 mg/L, inoculum concentration = 10%, incubation time = 24 h

Fig. 3

SEM image of isolated bacterial strain Serratia marcescens ABHI001

Fig. 4

Effect of the initial p-cresol concentration on degradation of p-cresol by bacteria Serratia marcescens ABHI001. Initial conditions: concentration of p-cresol = 50-500 mg/L, inoculum concentration = 10%, incubation time = 26 h

Fig. 5

Graph shows formation of various metabolites from p-cresol degradation by bacteria Serratia marcescens ABHI001. Initial conditions: concentration of p-cresol = 85 mg/L, inoculum concentration = 10%, incubation time = 18 h

Fig. 6

a GC analysis of p-cresol (control) before degradation; b GC analysis of p-cresol degradation after 18 h incubation with Serratia marcescens ABHI001

Fig. 7

a FT-IR analysis of p-cresol (control) before degradation b FT-IR analysis of p-cresol degradation after 18 h incubation with bacteria Serratia marcescens ABHI001