Biodegradation of a Complex Phenolic Industrial Stream by Bacterial Strains Isolated from Industrial Wastewaters

Alejandra Bartolomé,Carlos Vílchez,Juan-Luis Fuentes,José-Luis Gómez-Ariza,Gema Rodríguez-Moro,Juana Frontela,Mariana Lopes,Tamara García-Barrera,María Cuaresma,Jesús Lázaro

doi:10.3390/pr9111964

Abstract

Molecular and metabolomic tools were used to design and understand the biodegradation of phenolic compounds in real industrial streams. Bacterial species were isolated from an industrial wastewater treatment plant of a phenol production factory and identified using molecular techniques. Next, the biodegradation potential of the most promising strains was analyzed in the presence of a phenolic industrial by-product containing phenol, alfa-methylstyrene, acetophenone, 2-cumylphenol, and 4-cumylphenol. A bacterial consortium comprising Pseudomonas and Alcaligenes species was assessed for its ability to degrade phenolic compounds from the phenolic industrial stream (PS). The consortium adapted itself to the increasing levels of phenolic compounds, roughly up to 1750 ppm of PS; thus, becoming resistant to them. In addition, the consortium exhibited the ability to grow in the presence of PS in repeated batch mode processes. Results from untargeted metabolomic analysis of the culture medium in the presence of PS suggested that bacteria transformed the toxic phenolic compounds into less harmful molecules as a survival mechanism. Overall, the study demonstrates the usefulness of massive sequencing and metabolomic tools in constructing bacterial consortia that can efficiently biodegrade complex PS. Furthermore, it improves our understanding of their biodegradation capabilities.

Highlights

Phenolic compounds constitute a group of pollutants that are difficult to remove from the streams or by-products that contain them
Massive sequencing analysis was performed using samples from the liquid effluent treatment plant (ETP) of the industrial factory producing phenolic compounds. This analysis identified the bacterial species present in the ETP samples for their potential for biodegradation based on the available scientific information
The results from massive sequencing of liquid samples from the ETP were useful in selecting bacterial species with specific catabolic capabilities to degrade complex mixtures of phenolic compounds from real industrial streams

Summary

Introduction

Phenolic compounds constitute a group of pollutants that are difficult to remove from the streams or by-products that contain them. Phenolic pollutants are undergone to active transformations inside living organisms and generate more toxic electrophilic metabolites in a reaction mediated by the cytochrome P450 enzyme system. These active metabolites may bind to and damage DNA or other vital enzyme systems of living organisms [4,5]. There is an urgent need to design tools for efficiently removing phenolic compounds from industrial streams and industries to implement environmentally friendly technologies. These steps can eventually lead to economic benefits derived from, e.g., the use of by-products resulting from the remediation process

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Discussion

Conclusion