Identification of a New Heavy-Metal-Resistant Strain of Geobacillus stearothermophilus Isolated from a Hydrothermally Active Volcanic Area in Southern Italy.

Rosanna Puopolo,Simonetta Bartolucci,Danila Limauro,Angela Mormone,Giovanni Gallo,Monica Piochi,Gabriella Fiorentino,Patrizia Contursi

doi:10.3390/ijerph17082678

Abstract

Microorganisms thriving in hot springs and hydrothermally active volcanic areas are dynamically involved in heavy-metal biogeochemical cycles; they have developed peculiar resistance systems to cope with such metals which nowadays can be considered among the most permanent and toxic pollutants for humans and the environment. For this reason, their exploitation is functional to unravel mechanisms of toxic-metal detoxification and to address bioremediation of heavy-metal pollution with eco-sustainable approaches. In this work, we isolated a novel strain of the thermophilic bacterium Geobacillus stearothermophilus from the solfataric mud pool in Pisciarelli, a well-known hydrothermally active zone of the Campi Flegrei volcano located near Naples in Italy, and characterized it by ribotyping, 16S rRNA sequencing and mass spectrometry analyses. The minimal inhibitory concentration (MIC) toward several heavy-metal ions indicated that the novel G. stearothermophilus isolate is particularly resistant to some of them. Functional and morphological analyses suggest that it is endowed with metal resistance systems for arsenic and cadmium detoxification.

Highlights

Heavy metals are among the most persistent and toxic pollutants
We describe the isolation and characterization of a new thermophilic heavy-metal-resistant microorganism from the solfataric mud pool of Pisciarelli in the Campi Flegrei volcano located near Naples in Italy
With the aim of characterizing new thermophilic heavy-metal-resistant microorganisms, soil sampling was performed in a hydrothermal volcanic area near Naples in Italy, known as Pisciarelli

Summary

Introduction

Heavy metals are among the most persistent and toxic pollutants. From organic xenobiotics, which can be converted into non-harmful substances, they cannot be completely removed from the environment [1]. The prolonged exposure to heavy metals is responsible for several human diseases, as documented by the World Health Organization [5]. Arsenic and cadmium have been classified as carcinogenic compounds by the International Agency for Research on Cancer (IARC) in both humans and animals [6,7], while the exposure to lead is responsible for 3%. Of cerebrovascular disease worldwide [8]. Reduction of heavy-metal pollution is among the greatest challenges of the new century [9,10,11]

Methods

Results

Conclusion