Bioprospecting of Extremophilic Microorganisms to Address Environmental Pollution

Giovanni Gallo; Martina Aulitto; Patrizia Contursi; Danila Limauro; Simonetta Bartolucci; Gabriella Fiorentino

doi:10.3791/63453

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Method Article

Bioprospecting of Extremophilic Microorganisms to Address Environmental Pollution

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DOI:

10.3791/63453

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December 30th, 2021

Giovanni Gallo¹^,² , Martina Aulitto¹^,³ , Patrizia Contursi¹^,⁴ , Danila Limauro¹^,⁴ , Simonetta Bartolucci¹ , Gabriella Fiorentino¹^,⁴

¹Department of Biology, University of Naples Federico II, ²Institute of Polymers, Composites and Biomaterials (IPCB), Consiglio Nazionale delle Ricerche CNR, ³Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, ⁴BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Napoli Federico II

Summary

The isolation of heavy metal-resistant microbes from geothermal springs is a hot topic for the development of bioremediation and environmental monitoring biosystems. This study provides a methodological approach for isolating and identifying heavy metal tolerant bacteria from hot springs.

Abstract

Geothermal springs are rich in various metal ions due to the interaction between rock and water that takes place in the deep aquifer. Moreover, due to seasonality variation in pH and temperature, fluctuation in element composition is periodically observed within these extreme environments, influencing the environmental microbial communities. Extremophilic microorganisms that thrive in volcanic thermal vents have developed resistance mechanisms to handle several metal ions present in the environment, thus taking part to complex metal biogeochemical cycles. Moreover, extremophiles and their products have found an extensive foothold in the market, and this holds true especially for their enzymes. In this context, their characterization is functional to the development of biosystems and bioprocesses for environmental monitoring and bioremediation. To date, the isolation and cultivation under laboratory conditions of extremophilic microorganisms still represent a bottleneck for fully exploiting their biotechnological potential. This work describes a streamlined protocol for the isolation of thermophilic microorganisms from hot springs as well as their genotypical and phenotypical identification through the following steps: (1) Sampling of microorganisms from geothermal sites ("Pisciarelli", a volcanic area of Campi Flegrei in Naples, Italy); (2) Isolation of heavy metal resistant microorganisms; (3) Identification of microbial isolates; (4) Phenotypical characterization of the isolates. The methodologies described in this work might be generally applied also for the isolation of microorganisms from other extreme environments.

Introduction

The extreme environments on our planet are excellent sources of microorganisms capable of tolerating harsh conditions (i.e., temperature, pH, salinity, pressure, and heavy metals)¹^,², being Iceland, Italy, USA, New Zealand, Japan, Central Africa and India, the best-recognized and studied volcanic areas³^,⁴^,⁵^,⁶^,⁷^,⁸^,⁹. Thermophiles have evolved in harsh environments in a range of tem....