Methyl t-butyl ether-degrading bacteria for bioremediation and biocontrol purposes.

Giada D’Errico,Alberto Ritieni,Francesco Vinale,Ernesto Comite,Valeria Ventorino,Veronica Aloj,Sergio Bolletti Censi,Gavin R Flematti,Roberta Marra,Assunta Bottiglieri,Olimpia Pepe,Sabrina Sarrocco

doi:10.1371/journal.pone.0228936

Abstract

A total of fifteen potential methyl t-butyl ether (MtBE)-degrading bacterial strains were isolated from contaminated soil. They have been identified as belonging to the genera Bacillus, Pseudomonas, Kocuria, Janibacter, Starkeya, Bosea, Mycolicibacterium, and Rhodovarius. Bacillus aryabhattai R1B, S. novella R8b, and M. mucogenicum R8i were able to grow using MtBE as carbon source, exhibiting different growth behavior and contaminant degradation ability. Their biocontrol ability was tested against various fungal pathogens. Both S. novella R8b and B. aryabhattai were effective in reducing the development of necrotic areas on leaves within 48 hours from Botritys cinerea and Alternaria alternata inoculation. Whereas, M. mucogenicum effectively controlled B. cinerea after 72 hours. Similar results were achieved using Pythium ultimum, in which the application of isolated bacteria increased seed germination. Only M. mucogenicum elicited tomato plants resistance against B. cinerea. This is the first report describing the occurrence of bioremediation and biocontrol activities in M. mucogenicum, B. aryabhattai and S. novella species. The production of maculosin and its antibiotic activity against Rhizoctonia solani has been reported for first time from S. novella. Our results highlight the importance of multidisciplinary approaches to achieve a consistent selection of bacterial strains useful for plant protection and bioremediation purposes.

Highlights

Methyl tertiary-butyl ether (MtBE) is widely used as an oxygenated additive to increase the octane number and the combustion efficiency of gasoline for reducing emissions of carbon monoxide and volatile organic carbon [1,2]
The culture growth media used throughout this work were Potato Dextrose Agar (PDA), Potato Dextrose Broth (PDB), Luria Bertani Broth (LB), Luria Bertani Agar (LBA), Plate Count Agar, OXOID (PCA), Plate Count Broth, OXOID (PCB), and Malt Extract + Mycological Peptone (MEP)
Identification and selection of bacteria isolated from MtBE-contaminated soil

Summary

Introduction

Methyl tertiary-butyl ether (MtBE) is widely used as an oxygenated additive to increase the octane number and the combustion efficiency of gasoline for reducing emissions of carbon monoxide and volatile organic carbon [1,2]. This chemical compound is commonly utilized for about 80% of motor vehicle fuels in the USA (10–15%) and in Europe (1–10%). Due to its high solubility (49 g L-1), low organic carbon partition coefficient Koc (11 mg L-1) and poor natural degradation, MtBE is highly persistent in the environment [3].

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Results

Conclusion