Cr(VI) and lindane removal by Streptomyces M7 is improved by maize root exudates

Abstract

Environmental mixed pollution by both organic and inorganic compounds are detected worldwide. Phytoremediation techniques have been proposed as ecofriendly methods for cleaning up polluted sites. Several studies have demonstrated enhanced dissipation of contaminants at the root-soil interface through an increase in microbial activity caused by the release of plant root exudates (REs). The aim of this study was to evaluate the effectiveness for Cr(VI) and lindane removal by Streptomyces M7 cultured in a co-contaminated system in presence of maize REs. Our results showed when REs were added to the contaminated minimal medium (MM) as the only carbon source, microbial removal of Cr(VI) and lindane increased significantly in comparison to contaminant removal obtained in MM with glucose 1 g L . The maximum removal of 91% of lindane and 49.5% of Cr(VI) were obtained in the co-contaminated system. Moreover, Streptomyces M7 showed plant growth promoting traits which could improve plant performance in contaminated soils. The results presented in this study provide evidence that maize REs improved growth of Streptomyces M7 when REs were used as a carbon source in comparison to glucose. Consequently, lindane and Cr(VI) removal was considerably enhanced making evident the phytoremediation potential of the actinobacteria-plant partnership.

Evaluation of the effectiveness of a bioremediation process in experimental soils polluted with chromium and lindane

“…In contrast, the germination of the seeds of Z. mays was not inhibited in presence of chromium, probably due to its characteristic coating that provides protection to the embryo against external contaminants, preventing the indiscriminate passage of substances (Munzuroglu and Geckil, 2002;Srivastava et al, 2007). The tolerance of Z. mays to high levels of contamination makes this species potentially useful in phytoremediation strategies (Alvarez et al, 2012;Simon Sola et al, 2017;2019;Polti et al, 2011).…”

Effectiveness of the Zea mays-Streptomyces association for the phytoremediation of petroleum hydrocarbons impacted soils

“…In a phytoremediation scene, endophytic bacteria with specific metabolic capabilities could be able to degrade organic pollutants and to reduce both phytotoxicity and evapotranspiration of volatile compounds. Certainly, plant-associated bacteria have exceptional ability to improve plant growth and biomass production in polluted soils, due to their ability to produce plant growth-promoting (PGP) molecules (Fatima et al, 2016;Simon Sola et al, 2017Soleimani et al, 2010).…”

Gentle remediation options for soil with mixed chromium (VI) and lindane pollution: biostimulation, bioaugmentation, phytoremediation and vermiremediation

“…Degradation by actinobacteria was more pronounced in the amended soils, which had a higher concentration in the untreated soils at the end of the experiment. B. napus (Bn) significantly increased lindane degradation, probably by stimulating the microorganisms through exudates from the plant roots ( Simon Sola et al., 2017 ). Concomitantly, E. fetida (Ef) also stimulated lindane degradation, probably by improving the aeration of the soil, increasing lindane availability by mineralizing soil organic matter ( Rodriguez-Campos et al., 2014 ), and/or stimulating soil microbial communities ( Rodriguez-Campos et al., 2019 ).…”