Search

Biosurfactant-producing bacteria can be found in contaminated environments such as biopurification systems (BPS) for pesticide treatments. A total of 18 isolates were screened to determine their ability to produce extracellular biosurfactants, using olive oil as the main carbon source. Out of the eighteen isolates, two strains (C11 and C27) were selected for biosurfactant production. The emulsification activities of the C11 and C27 strains using sunflower oil was 58.4 and 53.7%, respectively, and 46.6 and 48.0% using olive oil. Using molecular techniques and MALDI-TOF, the strains were identified as

Recycled agroindustrial waste has been of great interest during the last decade as a low-cost and sustainable substrate for fermentation processes. The types of products, yields, and potential applications depend mainly on the waste composition, which varies in terms of proteins, carbohydrates, and/or polyphenolic compounds. The most commonly reported microbial products are enzymes, pigments, biosurfactants, antibiotics, and phenolic compounds for different industrial applications. Advances in research on novel wastes as nutrient sources and the optimization of fermentation processes can help these materials transition from laboratory applications to an industrial level. This review explores reports published in the last five years (2017–2022) on different types of agroindustrial waste and their utilization in the production of useful microbial products. The present scenario and future scope of agroindustrial waste as substrates for submerged and solid-state fermentation processes are also discussed. The information was analyzed considering two main topics: (i) agroindustrial waste as substrates for fermentation processes and (ii) high-added value products obtained by microbial conversion. This review contributes to future research endeavors to discover the key factors that will allow us to reach the market with sustainable microbial products.

Biosurfactants, a wide group of compounds produced by different microorganisms, generally have less toxicity and are more biodegradable than synthetic surfactants. Biosurfactant-producing bacteria can be found in contaminated environments, such as soils receiving pesticide applications constantly, or in pesticides treatment systems where microorganisms are adapted to biodegrading pesticides. Five pesticide-tolerant bacteria previously isolated from a pesticide biopurification system were evaluated as biosurfactant-producers. Pseudomonas rhodesiae C4, Rhodococcus jialingiae C8 and Pseudomonas marginalis C9 strains were positive in qualitative tests. Biosurfactant production by these strains using Bushnell-Haas medium with olive oil at 2% (w/v) was evaluated as emulsification index, oil displacement, droplet collapse test and surface tension. After 144 h, these strains showed a similar emulsification index of >55%. The two Pseudomonas (C4 and C9) strains showed lower superficial tension compared with Rhodococcus strain (C8)—34.47, 37.44 and 47.55 mN/m for strains C4, C9 and C8, respectively. The chemical characterization of the biosurfactants revealed the presence of glycolipids in P. rhodesiae (C4) and glycopeptides in P. marginalis (C9). The degradation of chlorpyrifos increased from 39.2% to 51.6% when biosurfactants produced by P.rhodesiae (C4) were added (10%) with respect to the control. Therefore, biopurification systems are a relevant source of biosurfactant-producing bacteria with environmental biotechnology applications.

In this study, we evaluated polyurethane foam (PF), volcanic rock (VR), and a modified plastic cap (MPC) as supports for the immobilization of organophosphorus (OP) pesticide-degrading actinobacterial strains. The colonization and activity of four streptomycetes were favoured by PF, which was selected as the carrier to use in a continuous stirred tank bioreactor (CSTR) that can be operated at increasing inflows of a pesticide mixture that contains the insecticides chlorpyrifos (CP) and diazinon (DZ). Our results demonstrate that the CSTR can be operated at flow rates of 10 and 40 mL h(−1) with greater than 85% removal of the pesticides in the short term. A significant decrease in the efficiency of CP removal was observed at the highest inflows into the reactor. The CP and DZ loading rates in the bioreactor ranged from 0.44 to 1.68 mg L(−1) h(−1) and from 0.50 to 2.17 mg L(−1) h(−1), respectively. Although the treated wastewater exhibited moderate toxicity for Raphanus sativus, a bioreactor inoculated with a mixed culture formed by Streptomyces spp. strains AC5, AC9, GA11 and ISP13 may provide an effective biotechnological strategy for the reduction of OP pesticide residues produced during agronomic and manufacturing practices and therefore prevent environmental pesticidal pollution.

In this study, we selected and characterized different pesticide-tolerant bacteria isolated from a biomixture of a biopurification system that had received continuous applications of a pesticides mixture. The amplicon analysis of biomixture reported that the phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were predominant. Six strains grew in the presence of chlorpyrifos and iprodione. Biochemical characterization showed that all isolates were positive for esterase, acid phosphatase, among others, and they were identified as Pseudomonas, Rhodococcus and Achromobacter based on molecular and proteomic analysis. Bacterial growth decreased as both pesticide concentrations increased from 10 to 100 mg L-1 in liquid culture. The Achromobacter sp. strain C1 showed the best chlorpyrifos removal rate of 0.072-0.147 d-1 a half-life of 4.7-9.7 d and a maximum metabolite concentration of 2.10 mg L-1 at 120 h. On the other hand, Pseudomonas sp. strain C9 showed the highest iprodione removal rate of 0.100-0.193 d-1 a half-life of 4-7 d and maximum metabolite concentration of 0.95 mg L-1 at 48 h. The Achromobacter and Pseudomonas strains showed a good potential as chlorpyrifos and iprodione-degrading bacteria.

White-rot and brown-rot fungi have complementary mechanisms to selectively degrade lignin and holocellullose, respectively. Thereby, a fungal co-culture of a white-rot and a brown-rot fungal could result in efficient strategy for a mild lignocellulosic biomass pretreatment. In this work, single, sequential and co-inoculation of the selective-lignin degrading white-rot fungus Ganoderma lobatum and the brown-rot fungus Gloeophyllum trabeum were evaluated as biological pretreatments of wheat straw to enhance enzymatic hydrolysis of cellulose. The single cultures of G. lobatum and G. trabeum exhibited preferential degradation of lignin and hemicellulose, respectively. The total crystallinity index decreased in samples pretreated with G. trabeum but not with G. lobatum. The pretreatment with single cultures of G. lobatum or G. trabeum increased glucose yields by 43.6% and 26.1% respectively compared to untreated straw. Although co-inoculation resulted in higher yields of glucose when compared with single cultures, only a slight synergistic effect between fungi was observed. Contrary, the sequential inoculation of G. lobatum incubated for 10 days followed by G. trabeum incubated for 10 days more showed a strong synergic effect on enzymatic hydrolysis. This sequential culture showed the highest glucose yield (191.5 mg g−1 wheat straw), 2.8-fold higher than untreated wheat straw, and 140–150% higher than the single-cultures of G. lobatum and G. trabeum, respectively.

Acid mine drainage, characterized by low pH and elevated heavy metal ion concentrations, causes severe harm to the environment. In this study, the feasibility of a new organic biomixture adsorbent for removing Fe3+, Zn2+, Cu2+ and Mn2+ metal ions from synthetic acid mine drainage was evaluated. This kinetic study showed fast metal ions adsorption within the first four to eight hours, and adsorption over 80% in the organic biomixture. The equilibrium adsorption isotherms resulted in a metal ion uptake greater than 84%, and the Freundlich model fitted well the data. The Freundlich affinity coefficient ( K f ) ranged from 1.44 to 3.82 in the following order: Zn2+>Cu2+>Fe3+>Mn2+. Scanning electron microscope images revealed the heterogeneous structure of the biomixture, and energy-dispersive X-ray analysis after adsorption confirmed the ability of the biomixture to remove the metal ions. In the fixed-bed column, the Thomas model described (R2>0.95) the adsorption process of metal ions contained in the treated acid mine drainage well. The adsorption capacity ( q 0 ) of this system resulted in 164.2 mg g−1, 129.2 mg g−1, 26.0 mg g−1 and 15.3 mg g−1 of Fe3+, Zn2+, Cu2+ and Mn2+, respectively. This study confirmed the efficiency of an organic biomixture to adsorb metal ions and provide new and valuable information for the future design of low-cost treatments to reduce acid mine drainage pollution.

Lignin is one of the main barriers to obtaining added-value products from cellulosic fraction of lignocellulosic biomass due to its random aromatic structure and strong association with cellulose and hemicellulose. Inorganic and organic compounds have been used as enzyme inducers to increase the ligninolytic potential of white-rot fungi, without considering their effect on the selectivity of degradation. In this study, the selective lignin degradation in wheat straw by Ganoderma lobatum was optimized using a central composite design to evaluate the combined effect of Fe2+ and Mn2+ as inducers of ligninolytic enzymes and NO3 − as an additional nitrogen source. Selective lignin degradation was promoted to maximize lignin degradation and minimize weight losses. The optimal conditions were 0.18 M NO3 −, 0.73 mM Fe2+, and 1 mM Mn2+, which resulted in 50.0% lignin degradation and 18.5% weight loss after 40 days of fungal treatment. A decrease in absorbance at 1505 and 900 cm−1 in fungal-treated samples was observed in the FTIR spectra, indicating lignin and cellulose degradation in fungal-treated wheat straw, respectively. The main ligninolytic enzymes detected during lignin degradation were manganese-dependent and manganese-independent peroxidases. Additionally, confocal laser scanning microscopy revealed that lignin degradation in wheat straw by G. lobatum resulted in higher cellulose accessibility. We concluded that the addition of enzyme inducers and NO3 − promotes selective lignin degradation in wheat straw by G. lobatum.

The dissipation of atrazine, chlorpyrifos and iprodione in a biopurification system and changes in the microbial and some biological parameters influenced by the rhizosphere of Lolium perenne were studied in a column system packed with an organic biomixture. Three column depths were analyzed for residual pesticides, peroxidase, fluorescein diacetate activity and microbial communities. Fungal colonization was analyzed by confocal laser scanning microscopy to assess the extent of its proliferation in wheat straw. The L. perenne rhizosphere enhanced pesticide dissipation and negligible pesticide residues were detected at 20–30 cm column depth. Atrazine, chlorpyrifos and iprodione removal was 82, 89 and 74% respectively in the first 10 cm depth for columns with vegetal cover. The presence of L. perenne in contaminated columns stimulated peroxidase activity in all three column depth sections. Fluorescein diacetate activity decreased over time in all column sections with the highest values in biomixtures with vegetal cover. Microbial communities, analyzed by PCR-DGGE, were not affected by the pesticide mixture application, presenting high values of similarity (>65%) with and without vegetal cover. Microbial abundance of Actinobacteria varied according to treatment and no clear link was observed. However, bacterial abundance increased over time and was similar with and without vegetal cover. On the other hand, fungal abundance decreased in all sections of columns after 40 days, but an increase was observed in response to pesticide application. Fungal colonization and straw degradation during pesticide dissipation were verified by monitoring the lignin autofluorescence loss.

The current study aimed to evaluate the removal of a pesticide mixture composed of the insecticides chlorpyrifos (CP) and diazinon (DZ) from liquid medium, soil and a biobed biomixture by a Streptomyces mixed culture. Liquid medium contaminated with 100 mg L−1 CP plus DZ was inoculated with the Streptomyces mixed culture. Results indicated that microorganisms increased their biomass and that the inoculum was viable. The inoculum was able to remove the pesticide mixture with a removal rate of 0.036 and 0.015 h−1 and a half-life of 19 and 46 h−1 for CP and DZ, respectively. The sterilized soil and biobed biomixture inoculated with the mixed culture showed that Streptomyces was able to colonize the substrates, exhibiting an increase in population determined by quantitative polymerase chain reaction (q-PCR), enzymatic activity dehydrogenase (DHA) and acid phosphatase (APP). In both the soil and biomixture, limited CP removal was observed (6–14%), while DZ exhibited a removal rate of 0.024 and 0.060 day−1 and a half-life of 29 and 11 days, respectively. Removal of the organophosphorus pesticide (OP) mixture composed of CP and DZ from different environmental matrices by Streptomyces spp. is reported here for the first time. The decontamination strategy using a Streptomyces mixed culture could represent a promising alternative to eliminate CP and DZ residues from liquids as well as to eliminate DZ from soil and biobed biomixtures. Fil: Briceño, Gabriela. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Vergara, Karen. Universidad de la Frontera. Nucleo Cientifico y Tecnológico en Recursos Naturales; Chile Fil: Schalchli, Heidi. Universidad de la Frontera. Nucleo Cientifico y Tecnológico en Recursos Naturales; Chile Fil: Palma, Graciela. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Tortella, Gonzalo. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Diez, María Cristina. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile

The native state of lignocellulosic biomass is highly resistant to enzymatic hydrolysis and the fermentation process of biofuel production. Brown-rot fungi use an extracellular Fenton system to degrade lignocellulosic biomass in the initial stages of decay. In this work, the combined effects of Mn2+, Fe2+, and NO3− inducers were evaluated based on the activities of hydrolytic enzymes and Fe3+ reduction as well as the catechol-type compound production during wheat straw pretreatment by the brown-rot fungus Gloeophyllum trabeum. Weight loss and chemical changes were evaluated to establish the culture conditions for stimulating wheat straw degradation using a central composite design. The results showed that weight loss and the Fe3+-reducing activity were promoted at the highest concentrations of Fe2+. A positive effect on catechol compound production by the addition of Mn2+ and NO3− was observed. Cellulase activity was increased at the highest concentration of NO3−. The multiple optimizations of G. trabeum culture conditions in wheat straw resulted in 11.3% weight loss and 0.47 total crystallinity index at 0.24 M NO3−, 0.95 mM Fe2+, and 0.85 mM Mn2+ after 40 days. The wheat straw pretreatment by G. trabeum for 10 days increased glucose recovery. The results indicated that the wheat straw pretreatment using G. trabeum with biodegradation inducers could be a complementary step to physicochemical pretreatment of lignocellulosic biomass for production of second-generation ethanol.

Potato waste was processed and used as a sole substrate for simultaneously producing antifungals and biopigments usingStreptomycesspp. Out of three differentStreptomycesisolates, strain SO6 stood out due to its ability to produce antifungals against economically important fungal phytopathogens and intracellular biopigments using potato waste powders without additional nutrients. This strain also showed the potential to secrete a broad range of enzymes for fermentation of eight sugars that could be involved in potato waste bioconversion. The results of the fermentation assay indicated thatStreptomycessp. strain SO6 degrades potato wastes during submerged fermentation, diminishing total dry weight and increasing reducing sugars from 0.3 to 3.6 mg·mL−1and total proteins from 70.6 to 187.7 μg·mL−1. The results showed thatStreptomycesstrain SO6 was able to convert the potato waste into 0.96 mg·g−1of diffusible antifungals and 1.75 mg·g−1of reddish-purple biopigments. On the contrary, an absence of pigment production was observed during the fermentation of the commercial medium used as reference. According to our results, replacement of commercial culture media with available low-cost agroindustrial wastes for producing bioactive chemicals is a real opportunity to enhance theStreptomycespigment production and antibiotic sustainability with cost-competitiveness. To our knowledge, this is the first report on the simultaneous production of biopigments and diffusible antifungal antibiotics produced byStreptomycesspp. using potato solid waste as the sole nutrient source.

This study provides the basis for implementing a continuous treatment system for wastewater containing a pesticide mixture formed by atrazine, iprodione, and chlorpyrifos. Two fungal strains (Verticilium sp. H5 and Metacordyceps sp. H12) isolated from a biomixture of a biopurification system were able to remove different pesticide concentrations (10 to 50 mg L−1) efficiently from the liquid medium; however, the half-life of the pesticides was reduced and characterized by a T1/2 of 5.4 to 9.2 d for atrazine, 3.7 to 5.8 d for iprodione, and 2.6 to 2.9 d for chlorpyrifos using the fungal consortium. The immobilization of the fungal consortium in alginate bead was effective, with the highest pesticide removal observed using an inoculum concentration of 30% wv−1. The packed-bed reactor with the immobilized fungal consortium, which was operated in the continuous mode at different flow rates (30, 60, and 90 mL h−1), required approximately 10 d to achieve removal efficiency (atrazine: 59%; iprodione: 96%; chlorpyrifos: ~85%). The bioreactor was sensitive to flow rate fluctuations but was able to recover performance quickly. The pesticide metabolites hydroxyatrazine, 3,5-dichloroaniline, and 3,5,6-trichloro-2-pyridinol were produced, and a slight accumulation of 3,5,6-trichloro-2-pyridinol was observed. Nevertheless, reactor removal efficiency was maintained until the study ended (60 d).

This study provides the basis for implementing a novel continuous treatment system for wastewater containing the pesticide atrazine (ATZ). Adsorption isotherms of ATZ from aqueous solution onto four biomixtures were determined. Based on the adsorption results, biomixture “B” (wheat straw, soil, and peat) was selected as the packing material for the fixed-bed column (FBC). The Response Surface Methodology (RSM) was used to optimize the combined effect of the inlet ATZ concentration (5–15 mg L−1), flow rate (10–50 mL h−1), and pH (4–8) of the FBC packed with biomixture “B” on ATZ removal. The dynamic behaviour of the FBC was investigated using the Thomas model under the optimal conditions obtained from the RSM. The results showed that pH was the determining factor in the adsorption process. Moreover, adsorption of ATZ decreased when the ATZ concentration and flow rate increased, especially at a basic pH. The optimum conditions for the adsorption of ATZ were a pH of 4.07, an influent ATZ concentration of 7.18 mg L−1, and a flow rate of 34.24 mL h−1 that resulted in the removal of 98.6% of the ATZ (corresponding to an adsorption capacity of 95.32 mg g−1). The Thomas model described the adsorption process to be well under optimal conditions (R 2 = 0 . 9829 ). The findings of this study demonstrate that biomixture “B” could be successfully used as a low-cost adsorbent to remove ATZ from aqueous solution under continuous conditions.

Intensive use of pesticides applied simultaneously in field to improve the effectiveness of pest control increase the environmental contamination, affecting the soil and water quality. Some of the commonly used pesticides are the insecticide chlorpyrifos and the fungicide iprodione; being thus critically essential to develop bioremediation methods to remove these contaminants by tolerant-bacteria. In this study we selected and characterized different pesticides-tolerant bacteria isolated from a biomixture of a biopurification system that had received continuous applications of a mixture of the pesticides chlorpyrifos and iprodione. Out of the 10 isolated bacterial colonies, only six strains presented adequate growth in presence of the both pesticides at 100 mg L-1. Biochemical and enzymatic characterization using API ZYM showed that all isolates (100%) were positive for esterase, leucine aminopeptidase, acid phosphatase, and naphthol-AS-BI-phosphohydrolase. According to the molecular level study of the 16S ribosomal gene and MALDI TOF/TOF MS, it was possible to determine that the isolated bacteria belong to the genera Pseudomonas, Rhodococcus and Achromobacter. Bacterial growth decreased proportionally (R2 > 0.96) as been as both pesticide concentrations increased from 10 to 100 mg L-1. Achromobacter sp. strain C1 showed the best chlorpyrifos removal (between 56–29%) after 120 h of incubation. On the other hand, the highest iprodione removal (between 91.2–98.9%) was observed for the Pseudomonas sp. strain C9, which was not detected after 48 h of incubation. According with their identification and ability to remove the contaminants, Achromobacter sp. strain C1 and Pseudomonas sp. strain C9 appear as promising microorganisms for their use in the treatment of matrices contaminated with chlorpyrifos, iprodione or their mixture. The results of this study will help to improve current technologies for the biodegradation of this commonly used insecticide and fungicide, in order to give a response to the problem of contamination by pesticides.

In this work, the biosynthesis of silver nanoparticles by Galega officinalis extract using AgNO3 as a precursor was reported. The reaction parameters for the biosynthesis and efficiency in their antimicrobial control against Escherichia coli, Staphylococcus aureus and Pseudomonas syringae were determined. For biosynthesis, a central composite design combined with response surface methodology was used to optimize the process parameters (pH, AgNO3 and extract concentration), and the design was assessed through the size distribution, zeta potential and polydispersity index of the nanoparticles. The results demonstrated that at pH 11, 1.6 mM of AgNO3 and 15% vv−1 of G. officinalis extract were the optimal reaction parameters. Transmission electron microscope (TEM) images and X-ray diffraction (XRD) confirmed the formation of small spherical silver nanoparticles. Antimicrobial assays showed a high inhibitory effect against E. coli, S. aureus and P. syringae, and that effect was larger with silver nanoparticles of a smaller size (23 nm). This work demonstrates that G. officinalis extract is a feasible medium for the synthesis of silver nanoparticles and that the control of the reaction parameters can determine the nanoparticle characteristics and therefore their antimicrobial effectiveness.

Fungal volatile secondary metabolites play important roles in mediating antagonistic and beneficial interactions among organisms. The effects of eight strains of white-rot fungi cultured on potato waste against the mycelial growth of Botrytis cinerea, Fusarium oxysporum and Mucor miehei were investigated using a bi-compartmented Petri dish assay. The chemical composition of volatile organic compounds released from the strain with the highest inhibitory effect was also investigated by headspace solid-phase microextraction and gas chromatography/mass spectrometry analysis. Of the eight white-rot fungi evaluated, Anthracophyllum discolor. Sp4 showed a high inhibitory activity against M. miehei (approximately 76%) and B. cinerea (approximately 20%). F. oxysporum was inhibited to a lesser extent (approximately 10%) by A. discolor and T. versiscolor. The gas chromatography/mass spectrometry analysis showed nine main volatile compounds released from A. discolor Sp4, among them are the sesquiterpenesα-bisabolene ...

Aims The aim of this study was to evaluate the synthesis of ligninolytic enzymes and some diffusible antifungal compounds by white-rot fungi using peels or discarded potato as the sole nutrient source. Methods and Results The strain Trametes hirsuta Ru-513 has been highlighted for its laccase activity (595 ± 33 U l−1), which is able to decolourise 87% of an anthraquinone dye using potato peels as the sole nutritional support. A native polyacrylamide gel of laccase proteins showed the presence of two isoenzymes, corresponding to proteins of 56 and 67 kDa, which were detected by SDS-PAGE. The antifungal activity of ethyl acetate extracts was evaluated by the agar diffusion method, where Anthracophyllum discolor Sp4 and Inonotus sp. Sp2 showed the highest inhibition zones of Mucor miehei. The fungal extracts also inhibited Fusarium oxysporum and Botrytis cinerea growth, with inhibition zones of up to 18 mm. The extract with the highest antifungal activity, from A. discolor Sp4 grown in discarded potato medium, was analysed using a gas chromatograph coupled to a mass spectrometer. Among the identified compounds, chlorinated aromatic compounds and veratryl alcohol were the most abundant compounds. Conclusions The results revealed the relevance of potato waste valorization for the sustainable production of ligninolytic enzymes and antifungal compounds. Significance and Impact of Study This study reports the synthesis of ligninolytic enzymes and diffusible antifungal compounds by white-rot fungi using potato wastes as the sole nutrient source and suggest a relationship between the enzymatic activity and the synthesis of antifungal compounds. These compounds, and the synthesis of halogen compounds by white-rot fungi using agroindustrial wastes have been poorly studied before. This article is protected by copyright. All rights reserved.

Se determino la capacidad antioxidante (CA), antocianinas totales (AT) y fenoles totales (FT) de frutos de calafate de cuatro localidades del sur de Chile (El Blanco, Lonquimay, Manihuales y Temuco) utilizando los metodos del radical libre 2,2-difenil -1- picrilhidrazil (DPPH) y la capacidad de inhibir la oxidacion del acido linoleico, asi como pH diferencial y el metodo de Folin-Ciocalteu. Ademas, se identificaron los compuestos fenolicos por medio de HPLC-DAD (Cromatografia liquida de alta eficacia- con Deteccion por Arreglo de Diodos). Los resultados mostraron que los FT variaron significativamente segun la localidad, destacandose Manihuales con 34,9 mg GAE g-1 de fruta seca. La CA vario de acuerdo con la metodologia, por DPPH vario significativamente entre localidades, y de nuevo se destaco Manihuales con los valores mas altos de CA (9,4 mg de TE g-1 de frutas secas). La inhibicion de la oxidacion del acido linoleico revelo que no hubo diferencias significativas entre Temuco y El Blanco, presentando Manihuales el valor mas alto (0,25 mg de TE g-1 de fruta seca). Las AT mostraron diferencias significativas entre localidades, siendo El Blanco el mayor (0,64 mg de cianidina g-1 fruta seca). En relacion a los compuestos fenolicos, fueron identificados acido galico, acido clorogenico, acido cafeico, acido cumarico, acido ferulico, y flavonoides como rutina, miricetina, quercetina y kaempferol. Estos compuestos variaron de acuerdo a la localidad: Temuco mostro un valor mas alto de acido cumarico; Lonquimay en acido clorogenico, acido cafeico, acido cumarico, y flavonoides como rutina y quercetina; Manihuales en acido galico, acido clorogenico, acido cafeico, acido ferulico y favonoides como la rutina y la quercetina; El Blanco en acido cafeico y flavonoides como miricetina, quercetina y kaempferol. La CA se correlaciono positivamente con FT (DPPH r=1; acido linoleico r=0,84). Por el contrario, se obtuvo una baja correlacion entre la CA y AT (DPPH r=0,31; acido linoleico r=-0,28), y entre FT y AT (r=0,27). Se concluye que los frutos de calafate de diferentes areas geograficas del sur de Chile tienen diferencias estadisticamente significativas en su CA, FT, AT y compuestos fenolicos, siendo Manihuales el area que presento los valores mas altos para estos parametros. La composicion quimica de los frutos tambien vario dependiendo del origen de las muestras.

Fungi are an extraordinary and immensely diverse group of microorganisms that colonize many habitats even competing with other microorganisms. Fungi have received recognition for interesting metabolic activities that have an enormous variety of biotechnological applications. Previously, volatile organic compounds produced by fungi (FVOCs) have been demonstrated to have a great capacity for use as antagonist products against plant pathogens. However, in recent years, FVOCs have been received attention as potential alternatives to the use of traditional pesticides and, therefore, as important eco-friendly biotechnological tools to control plant pathogens. Therefore, highlighting the current state of knowledge of these fascinating FVOCs, the actual detection techniques and the bioactivity against plant pathogens is essential to the discovery of new products that can be used as biopesticides.

Chlorpyrifos (CP) is an organophosphorus pesticide (OP) widely used in agriculture. Evidence of CP residues in soil, water and food has generated an urgent need to develop treatment systems that avoid possible damage to human health and the environment. In this study, eight diazinon-degrading Streptomyces strains were evaluated for their ability to remove CP as the only carbon source from a liquid medium. Single cultures removed 32–74% of CP, and most of the strains incremented their biomass. Additionally, changes in the protein profile were found. Protein extract analyses demonstrated that four organisms exhibited the enzyme organophosphorus hydrolase (OPH); therefore, the Streptomyces spp. AC5, AC9, GA11 and ISP13 strains were used as a mixed culture to study the removal of CP and their main metabolite 3,5,6-trichloro-2-pyridinol (TCP). Our results showed a CP removal rate of 0.019–0.034 h−1 a half-life of 20–36 h and a maximum TCP concentration of 0.32 mg L−1. The mixed culture used TCP to grow, and up to 58% was removed from the medium. Glucose addition decreased biomass duplication time of the culture and also accelerated pesticide depletion from the medium. Viability analysis showed that after CP and TCP exposure, over 78% of the cells survived. Finally, the mixed culture of Streptomyces spp. can simultaneously remove four OPs, reaching a maximum removal of 69.3% and 33.6% for thiophosphotriester and phosphorothiolester compounds respectively. Fil: Briceño, G.. Universidad de La Frontera; Chile Fil: Schalchli, H.. Universidad de La Frontera; Chile Fil: Mutis, A.. Universidad de La Frontera; Chile Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Palma, G.. Universidad de La Frontera; Chile Fil: Tortella, G. R.. Universidad de La Frontera; Chile Fil: Diez, M. C.. Universidad de La Frontera; Chile

It is possible to incorporate a lot of natural antioxidants into the human organism by consuming berries which can prevent diseases generated by the action of free radicals. Antioxidants neutralize free radicals and thus protect the organism from the oxidative damage of lipids, proteins, and nucleic acids. Berries stand out as one of the richest sources of antioxidant phytonutrients among various fruits and vegetables. The objective of this research was to determine antioxidant capacity (AC), total anthocyanins (TA), and total phenols (TP) of wild and cultivated berries in different localities of La Araucanía and Los Ríos Regions in Chile. These parameters were analyzed by using the free radical 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) method, pH-differential, and Folin-Ciocalteu method. Percentages of DPPH discoloration of different berries studied were between 67.8% and 95.3% for red sarsaparilla and rosehip, respectively. Maqui berries showed a significantly higher TA content (2240.2 and 1445.3 mg L-1 cyanidin 3-glucoside) than other berries, and a mean for all berries of 335.5 mg L-1. Higher phenol content levels were obtained in two cultivars of saskatoon (773.9 and 1001.9 mg L-1 gallic acid) and wild rosehip (1457.0 and 1140.4 mg L-1 gallic acid). We conclude that there are significant differences in antioxidant capacity of wild and cultivated Chilean berries in this study which show a strong correlation between AC and TP content.Por medio del consumo de berries es posible incorporar al organismo una gran cantidad de antioxidantes capaces de prevenir múltiples enfermedades generadas por la acción de los radicales libres. Los antioxidantes actúan neutralizando los radicales libres y de esta forma protegen al organismo del daño oxidativo de lípidos, proteínas y ácidos nucleicos. Entre variadas frutas y hortalizas, se destacan los berries como una de las fuentes más ricas en fitonutrientes antioxidantes. El objetivo de esta investigación fue determinar la capacidad antioxidante (AC), antocianinas totales (TA) y el contenido de fenoles totales (TP), de berries silvestres y cultivados en diferentes localidades de la Región de La Araucanía y Región de Los Ríos (Chile). Para evaluar estos parámetros se utilizó el método de radicales libres 2,2-difenil-2- picrilhidrazilo (DPPH), pH diferencial y Folin-Ciocalteu, respectivamente. Los porcentajes de decoloración del DPPH estuvieron comprendidos entre 67,8% para zarzaparrilla roja y 95,3% para rosa mosqueta. El maqui presentó un contenido de AT significativamente mayor (2240,2 y 1445,3 mg L-1 cianidina 3-glucósido) que el resto de los berries, el promedio de AT fue de 335,5 mg L-1. En cuanto al contenido FT los mayores niveles se obtuvieron en los dos cultivares de saskatoon (773,9 y 1001,9 mg L-1 ácido gálico) y en rosa mosqueta silvestre (1457,0 y 1140,4 mg L-1 de ácido gálico). En este estudio se concluye que existen diferencias significativas en la capacidad antioxidante de frutos silvestres y cultivados en Chile, observándose una fuerte correlación entre el CA y el contenido de FT.

Actinobacteria identified as Streptomyces spp. were evaluated for their ability to remove diazinon as the only carbon source from a liquid medium. Single cultures of Streptomyces strains were exposed to diazinon at a concentration of 50 mg L-1. After 96 h incubation, six of the eight cultures grew and five strains showed an increase in their total protein concentrations and changes in their protein profile. Up to 32% of the diazinon was removed by the single Streptomyces cultures. A compatibility assay showed that the different Streptomyces species were not antagonistic. Twenty-six mixed cultures were then prepared. Diazinon removal was increased when mixed cultures were used, and maximum diazinon removal of 62% was observed when the Streptomyces spp. strains AC5, AC9, GA11 and ISP13 were mixed; this was defined as the selected mixed culture (SMC). Diazinon removal was positively influenced by the addition of glucose into the liquid medium. Our study showed a diazinon degradation rate of 0.025 h-1, half-life of 28 h-1 and 2-isopropyl-6-methyl-4-pyrimidinol (IMHP) production of 0.143 mg L h-1. Rapid diazinon hydrolysis to IMHP was associated with a decrease in the pH of the medium as a consequence of microbial glucose metabolism and organic acid exudation. Moreover, the SMC of Streptomyces was able to remove IMHP. This work constitutes a new, if not the only, report on diazinon degradation by mixed cultures of Streptomyces spp. Given the high levels of diazinon removal, the SMC formed by four Streptomyces strains has the potential to be used to treat the diazinon present in environmental matrices. Fil: Briceño, G.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Schalchli, H.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Rubilar, O.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Tortella, G.R.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Mutis, A.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Palma, G.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile Fil: Diez, M.C.. Universidad de La Frontera. Núcleo Científico y Tecnológico en Recursos Naturales; Chile

Wheat (Triticum aestivum L.) is known for its ability to produce and release al- lelopathic compounds, which have potential for controlling weeds and diseases. Previous reports have shown the fungitoxic effects of allelochemicals present in wheat. Thus, these compounds can be exuded by roots to protect the tissues directly affected by Gaeumannomyces graminis var. tritici (Ggt) fungus that causes wheat take-all disease. The aim of this research was to evaluate in vitro the allelopathic ef- fect of root exudate extracts from four Chilean wheat cultivars on Ggt growth. Root exudates were released from wheat seedlings to a sterile culture medium without nutrients. Afterward, the exudates in the culture medium were separated by liquid- liquid extraction using ethyl acetate. Eight different concentrations were tested for each cultivar. The results showed that the degree to which the extracts strongly in- hibit the phytopathogen growth is highly dependent on both the concentration and the cultivar. The root extract of the Domo cultivar was significantly active against Ggt (MIC=0.36 mg mL -1 ). IC 50 and MIC values obtained for Dollinco and Domo root exudate extracts showed toxicity to Ggt. These findings may be considered in future studies related to the use of allelopathic potential as a selection factor in order to reduce the yield losses caused by various take-all diseases, as an alternative to chemical controls.

The antifungal activity of molecular identified Chilean saprobiontic fungi, Trichoderma viride, Schizophyllum commune and Trametes versicolor, on the fungal plant pathogens Botrytis cinerea and Fusarium oxysporum, and the saprotrophic mould Mucor miehei was investigated using two types of inhibition bioassay: (1) bi-compartmented Petri dishes and (2) two Erlenmeyer flasks connected by their upper parts. The chemical composition of volatile organic compounds (VOCs) released by saprobiontic fungi was also investigated using headspace solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC-MS) analysis. Of the saprobiontic fungi evaluated, one isolate of S. commune showed the highest inhibitory activity against B. cinerea and M. miehei, 86.0±5.4 and 99.5±0.5% respectively. The volatile profiles of fungal isolates were shown to contain a different class of compounds. The major components in the headspace of mycelial cultures were 6-pentyl-α -pyrone (T. viride), ethanol and β -bisabolol...

It is possible to incorporate a lot of natural antioxidants into the human organism by consuming berries which can prevent diseases generated by the action of free radicals. Antioxidants neutralize free radicals and thus protect the organism from the oxidative damage of lipids, proteins, and nucleic acids. Berries stand out as one of the richest sources of antioxidant phytonutrients among various fruits and vegetables. The objective of this research was to determine antioxidant capacity (AC), total anthocyanins (TA), and total phenols (TP) of wild and cultivated berries in different localities of La Araucania and Los Rios Regions in Chile. These parameters were analyzed by using the free radical 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) method, pH-differential, and Folin-Ciocalteu method. Percentages of DPPH discoloration of different berries studied were between 67.8% and 95.3% for red sarsaparilla and rosehip, respectively. Maqui berries showed a significantly higher TA content (2240.2 and 1445.3 mg L-1 cyanidin 3-glucoside) than other berries, and a mean for all berries of 335.5 mg L-1. Higher phenol content levels were obtained in two cultivars of saskatoon (773.9 and 1001.9 mg L-1 gallic acid) and wild rosehip (1457.0 and 1140.4 mg L-1 gallic acid). We conclude that there are significant differences in antioxidant capacity of wild and cultivated Chilean berries in this study which show a strong correlation between AC and TP content.

espanolEl objetivo de esta investigacion fue evaluar el potencial alelopatico de cincuenta cultivares de trigo sobre cuatro especies de malezas frecuentes en el cultivo en la zona sur de Chile. El diseno experimental fue en bloques al azar con cuatro repeticiones. Se evaluo largo radical mayor de la especie receptora (maleza) a los 18 dias de establecida esta. Los datos transformados a porcentaje de inhibicion del largo radical de la especie receptora en relacion al testigo fueron sometidos a ANDEVA, Analisis Cluster y Tukey (P ? 0.05). Se constato que el efecto alelopatico de los cultivares sobre las especies de malezas evaluadas en la mayoria de los casos fue inhibitorio y ocasionalmente potenciador sobre algunas de estas malezas. Los cultivares mas inhibitorios fueron Perquenco, Metrenco, Aztec y Baroudeur (rango: 57-65%) y los con menor inhibicion Dollinco, Tilburi, Tukan y Bingo (rango: 20-29%). Los otros cultivares se ubicaron en un rango intermedio de inhibicion. La interaccion alelopatica entre los cultivares de trigo y las malezas evaluadas difirio significativamente. En aquellas de mayor sensibilidad la secuencia fue la siguiente: Spergula arvensis (+10 a 88%), Rumex acetosella (+8 a 70%), Avena fatua (+36 a 74%) y Vulpia bromoides (+11 a 68%). Englishhe objective was: to evaluate the allelopatic potential of 50 wheat cultivars on four weed species associated with this culture in south Chile. The experimental design was in blocks with four repetitions. The longest main root of the receptive species (weed) was evaluated eighteen days after the establishment of the last one. The transformed data into percentage of inhibition of root length of the receptive species in relation to the control was analyzed using ANDEVA, cluster analysis and Turkey (P

Los objetivos de esta investigación fueron: validar el método ECAM (Wu et al., 2000a) y determinar el potencial alelopático de cincuenta cvs. de trigo cultivados en Chile sobre ballica anual (Lolium rigidum) var. Wimmera. El diseño experimental fue completamente al azar y en bloque con cuatro repeticiones. Se evaluó largo radical mayor de la especie receptora (ballica) a los diez días de establecida. Los datos transformados a porcentaje de inhibición del largo radical de la especie receptora en relación al testigo fueron sometidos a ANDEVA, Análisis Cluster y Duncan o Tukey (P=0.05). El método ECAM modificado fue eficaz para evaluar el potencial alelopático de los cincuenta cultivares de trigo y, en general, se produjo inhibición del crecimiento radical de ballica con un rango de inhibición de 20 a 80%. Los cultivares más alelopáticos fueron Tukan, Oracle y Castaño y los con menor potencial Baroudeur, Paillaco y Domo.

Interactions between microorganisms and root exudates in a biobed system with vegetal (grass) cover could enhance pesticide degradation. Otherwise, a high water load may generate high concentrations of pesticides in lixiviates. We studied the effect of the vegetal cover on the degradation of a mixture of atrazine (ATZ), chlorpyrifos (CHL) and iprodione (IPR) (35 mg L -1 each) in a biobed system operated with two different hydraulic loads (0.6 and 1.2 L of tap water per day). The concentration of the pesticides and their main metabolites were measured in the lixiviates during 60 days, as well as in the biomixtures at the end of the study. Dehydrogenase activity in the biomixtures and organic acid exudation from the vegetal cover were also analysed. The vegetal cover diminished the lixiviation of pesticides and their metabolites mainly at the lower hydraulic load used. The degradation of the pesticides was high (>95%) and increased in biobeds with vegetal cover and low hydraulic load. Degradation metabolites of CHL and IPR were formed during pesticide degradation; however they were degraded in the biobed and were not detected in lixiviates at the end of the study. In general, an increase in organic acid exudation by vegetal cover was observed caused by chemical stress after pesticide application. The increase was similar at both hydraulic loads. Efficient colonisation of wheat straw by fungi was observed by confocal microscopy.