Cell immobilization technique for the enhanced removal of lindane using Streptomyces strains isolated from Northwestern Argentina

Lindane (γ-HCH) is an organochlorine insecticide which has a negative effect as a pollutant agent of soil, water and sediments. Nowadays it has been banned in almost all countries of the world, but its residues still remain in the environment. In this context, bioremediation, involving the use of microorganisms to degrade environmental contaminants, has received much attention as an effective biotechnological approach to clean up this kind of pollutants. Moreover, cell immobilization has been shown to present diverse advantages over conventional systems using free cells, such as the possibility of employing higher cell density, easier separation of cells from the system, repeated use of cells and better protection of cells from harsh environments. Thereby, this chapter compiles information about: 1) the advantages and limitations of the use of immobilized cells, 2) the comparison between free or immobilized cells for lindane removal by single cultures of actinobacteria, isolated from polluted environments in the northwest of Argentina, and 3) lindane removal by free and immobilized consortia of Streptomyces spp.Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad de Administración Territorial; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; ArgentinaFil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentin

Enantiomer signature and carbon isotope evidence for the migration and transformation of DDTs in arable soils across China

Due to the adverse impact of DDTs on ecosystems and humans, a full fate assessment deems a comprehensive study on their occurrence in soils over a large region. Through a sampling campaign across China, we measured the concentrations, enantiomeric fractions (EFs), compound-specific carbon isotope composition of DDT and its metabolites, and the microbial community in related arable soils. The geographically total DDT concentrations are higher in eastern than western China. The EFs and δ(13)C of o,p’-DDT in soils from western China show smaller deviations from those of racemic/standard compound, indicating the DDT residues there mainly result from atmospheric transport. However, the sources of DDT in eastern China are mainly from historic application of technical DDTs and dicofol. The inverse dependence of o,p’-DDT and p,p’-DDE on temperature evidences the transformation of parent DDT to its metabolites. Initial usage, abiotic parameters and microbial communities are found to be the main factors influencing the migration and transformation of DDT isomers and their metabolites in soils. In addition, a prediction equation of DDT concentrations in soils based on stepwise multiple regression analysis is developed. Results from this study offer insights into the migration and transformation pathways of DDTs in Chinese arable soils, which will allow data-based risk assessment on their use

An overview on microbial degradation of lindane

Lindane is a cyclic, saturated and highly chlorinated pesticide with a broad spectrum, which has been used worldwide for many decades to control a variety of pests, and also in human health and veterinary. Afterward, it has been demonstrated that lindane and its isomers may cause serious damage to health in the short and long term. Besides, lindane is known to be persistent in the environment and tends to bioaccumulate along the food chain. Thus, lindane residues remain in the environment for a long time and have been recently found in water, soil, sediments, plants, and animals all over the world, and even in human fluids and tissues. In this context, nowadays, scientists, working all over the world, are involved in developing lindane remediation technologies including physical, chemical, and biological techniques. This article provides updated information on the biologic degradation of lindane using different microorganisms such as bacteria, fungi, and algae, under both aerobic and anaerobic conditions.Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentin

Pesticides Removal Using Actinomycetes and Plants

The γ-hexachlorocyclohexane (γ-HCH, lindane) is an organochlorine pesticide used in agriculture and medicine to world level. It has a big tendency to bioaccumulation into the environment so is listed as a priority pollutant by the US EPA. Hence the development of new technologies to remediate these sites using microorganisms is every time more necessary. The actinomycetes are Gram-positive bacteria with great potential to bioremediate xenobiotics. One strain, Streptomyces sp. M7, isolated from organochlorine pesticide contaminated sediment, was selected for its capacity to grow in presence of lindane as only carbon source. This microorganism was cultured in soil extract medium added of lindane 100 μg L−1, obtaining a maximal growth of 0.065 mg mL−1, similar to the control, with a highest lindane remotion of 70.4 % at 30°C and pH 7. When different initial pesticide concentrations (100, 150, 200, and 300 μg L−1) were added in soil medium, an increment of the microbial growth was detected in all the concentrations tested. Also a diminution of the residual lindane concentration was determined in the soil samples in relation to controls without bacteria (29.1, 78.0, 38.8, and 14.4 %, respectively). Besides, it was determined the optimum Streptomyces sp. M7 inoculum when lindane 100 μg kg−1soil was added to the soil sample. The optimum inoculum was 2 g kg−1 soil for obtaining the most efficiently bioremediation process: the lindane removal in these conditions was 67.8 % at 28 days of incubation. Later it was considered necessary to know the pesticide effects on maize plants seeded in lindane-contaminated soil previously inoculated with Streptomyces sp. M7. Lindane concentrations of 100, 200, and 400 mg kg−1 soil did not affect the germination and vigor index of maize plants seeded in contaminated soils without Streptomyces sp. M7. When this microorganism was inoculated at the same conditions, a better vigor index was observed and 68 % of lindane was removed. In this connection, Streptomyces sp. M7 was grown on culture medium in presence of root exudates of maize, spiked with 1.66 mg L−1 of lindane. The highest level of pesticide removal obtained on this condition suggests that root exudates enhanced removal of lindane by the bacterium. On the other hand, little information is available on the ability of biotransformation of organochlorine pesticides by actinomycete strains. It was demonstrated that Streptomyces sp. M7 possesses the LinA enzyme that catalyzes dehydrochlorination of lindane to 1,3,4,6-tetrachloro-1,4-cyclohexadiene (1,4-TCDN) via γ-pentachlorocyclohexene (γ-PCCH). These results confirm that actinomycete strains could be considered one of the most promising bacterial groups for lindane biodegradation in contaminated environment. Particularly, Streptomyces sp. M7 could be used for this purpose.Fil: Alvarez, Analia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; ArgentinaFil: Cuozzo, Sergio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin