Evaluation of Arthrobacter aurescens Strain TC1 as Bioaugmentation Bacterium in Soils Contaminated with the Herbicidal Substance Terbuthylazine

Abstract

In the last years the chloro-s-triazine active substance terbuthylazine has been increasingly used as an herbicide and may leave residues in the environment which can be of concern. The present study aimed at developing a bioaugmentation tool based on the soil bacterium Arthrobacter aurescens strain TC1 for the remediation of terbuthylazine contaminated soils and at examining its efficacy for both soil and aquatic compartments. First, the feasibility of growing the bioaugmentation bacterium inocula on simple sole nitrogen sources (ammonium and nitrate) instead of atrazine, while still maintaining its efficiency to biodegrade terbuthylazine was shown. In sequence, the successful and quick (3 days) bioremediation efficacy of ammonium-grown A. aurescens TC1 cells was proven in a natural soil freshly spiked or four-months aged with commercial terbuthylazine at a dose 10× higher than the recommended in corn cultivation, to mimic spill situations. Ecotoxicity assessment of the soil eluates towards a freshwater microalga supported the effectiveness of the bioaugmentation tool. Obtained results highlight the potential to decontaminate soil while minimizing terbuthylazine from reaching aquatic compartments via the soil-water pathway. The usefulness of this bioaugmentation tool to provide rapid environment decontamination is particularly relevant in the event of accidental high herbicide contamination. Its limitations and advantages are discussed.

Genome-Scale reconstruction ofPaenarthrobacter aurescensTC1 metabolic model towards the study of atrazine bioremediation

“…Supplementing the medium with glucose enhanced growth both in silico and in vitro , while the addition of ammonia had not shown an effect on growth. This is in accordance with previous work stating that P.aurescens TC1 growth is not inhibited by nitrogen sources such as ammonia 22 , unlike the inhibition of atrazine degradation in Pseudomonas sp. strain ADP in nitrogen rich environments 52 .…”

“…In addition to glucose, several carbon sources were previously reported to enhance growth of several strains of Arthrobacter species in atrazine containing media 21,22,53 . To identify additional media modifications that can potentially increase atrazine degradation, we simulated growth in 123 different media combinations, each supplementing the atrazine containing minimal mineral media with a single exchange metabolite.…”

“…Moreover, This bacterium was previously reported to biodegrade atrazine much more efficiently than most atrazine degrading bacteria including Pseudomonas sp. ADP 22 . Intermediates, created in the degradation process are further metabolized by the organism and can provide sole sources for carbon and nitrogen 18 .…”

Pyrethroid-Degrading Microorganisms and Their Potential for the Bioremediation of Contaminated Soils: A Review

“…Among the biological approaches, which include attenuation, biostimulation, and bioaugmentation, the last one seems to be the most promising for the removal of pyrethroids and their residues from soil (Chen et al, 2012c ; Zhao et al, 2013 ; Cycoń et al, 2014 ; Akbar et al, 2015a ). The usefulness of bioaugmentation with microorganisms in the clean-up of polluted soil has also been demonstrated some years ago in relation to other pesticides including organochlorinated pesticides (Kataoka et al, 2011 ; Sáez et al, 2014 ), organophosphorus pesticides (Cycoń et al, 2013 ; Aceves-Diez et al, 2015 ), triazines (Wang et al, 2013 ; Silva et al, 2015 ), carbamate (Pimmata et al, 2013 ), chloroacetamide (Zheng et al, 2012 ), benzimidazole (Wang et al, 2010 ), and derivatives of phenoxyacetic acid (Önneby et al, 2014 ). The promising results of these studies caused an increasing interest in screening new pyrethroid-degrading strains and searching for more effective bioremediation approaches (Chen et al, 2011a ; Zhao et al, 2013 ; Cycoń et al, 2014 ; Liu et al, 2014 ; Akbar et al, 2015b ; Zhang et al, 2016 ).…”

Heavy Metal Contamination in Soil and Brown Rice and Human Health Risk Assessment near Three Mining Areas in Central China

“…China is the largest producer and consumer of rice in the world, contributing about 30% of the total global rice output. As a cereal grain, rice is the most widely consumed staple food, supporting a large part of the world's human population, especially in Asia [ 13 , 14 ]. However, the consumption of rice contaminated with toxic heavy metals has been reported to be linked closely to health impacts.…”