Soil bioremediation through flagellated bacteria: unravelling the mechanisms for enhancing bacterial tactic response

Descripción del proyecto

Mejora de la forma en que los microorganismos eliminan contaminantes edáficos

La eliminación de contaminantes presentes en el medio ambiente empleando procesos biológicos se conoce como biorremediación. Este método permite degradar, descomponer y eliminar contaminantes mediante el empleo de microorganismos. El proyecto BIOTAC, financiado con fondos europeos, empleará un método novedoso: la aplicación a macroescala de mecanismos a microescala que permiten que las bacterias flageladas accedan a contaminantes con una disponibilidad limitada a través de mecanismos de dispersión mejorada. En concreto, el proyecto se centrará en los mecanismos funcionales de las bacterias flageladas que permiten mejorar la biodisponibilidad. Mediante el empleo de efectores biológicos y químicos seleccionados cuidadosamente que favorecen el movimiento bacteriano mediado por flagelos y la comovilización de cepas de bacterias sésiles degradadoras, el proyecto desarrollará estrategias para mejorar el desplazamiento bacteriano a fuentes contaminantes. También se llevará a cabo un análisis de los riesgos y beneficios de la nueva tecnología de biorremediación.

Objetivo

Bacterial dispersal is a key driver of pollutant turnover in contaminated soils. Flagellated bacteria able to degrade organic pollutants hold tactic responses to a variety of stimuli and reach pollutant hotspots, enhancing the access to poorly bioavailable carbon sources by steepening pollutant concentration gradients at interfaces. However, bacterial motility in porous media is often restricted due to high cell deposition rates and adhesion to soil particles, and in this sense, the modulating role of biological and chemical effectors is decisive. The aim of BIOTAC is the study of the mechanisms operating with flagellated bacteria for bioavailability enhancements and, therefore, a faster turnover of persistent organic pollutants in soils, including polycyclic aromatic hydrocarbons and a pesticide, lindane. We will study, at the microorganism scale, the role of bacterial taxis in chemical gradients (chemotaxis), as well as other tactic responses (repellence, surface taxis) in pollutant bioavailability, modelling and integrating them with other microbial adaptations (i.e. biofilm formation and the production of biosurfactants). We will develop strategies to improve bacterial transport to pollutant sources, using carefully selected biological and chemical effectors (respectively including, mycelial networks and organic compounds -root exudates, humic acids, and fertilizers), that favour flagella-mediated taxis, and co-mobilization of immotile degrading strains. The originality and innovation of the project lies on the macroscale projection of the microscale mechanisms underlying the access of self-propelled bacteria to limitedly available contaminants through an enhanced dispersal. Through experimental and modelling approaches, aiming at balancing biosorption and colloidal transport of the pollutants against biodegradation rates, the project will perform a risk and benefit analysis of the new bioremediation technology.