RESUMEN
AIMS: The aim of this study was to evaluate the synthesis of ligninolytic enzymes and some diffusible antifungal compounds by white-rot fungi (WRF) using peels or discarded potato as the sole nutrient source. METHODS AND RESULTS: The strain Trametes hirsuta Ru-513 highlighted for its laccase activity (595 ± 33 U l-1 ), which is able to decolourize 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 THE STUDY: This study reports the synthesis of ligninolytic enzymes and diffusible antifungal compounds by WRF using potato wastes as the sole nutrient source and suggests a relationship between the enzymatic activity and the synthesis of antifungal compounds. These compounds and the synthesis of halogen compounds by WRF using agro-industrial wastes have been poorly studied before.
Asunto(s)
Agaricales/metabolismo , Antifúngicos/metabolismo , Proteínas Fúngicas/metabolismo , Lacasa/metabolismo , Solanum tuberosum/microbiología , Residuos Sólidos/análisis , Trametes/enzimología , Agaricales/química , Agaricales/crecimiento & desarrollo , Colorantes/metabolismo , Medios de Cultivo/metabolismo , Electroforesis en Gel de Poliacrilamida , Proteínas Fúngicas/química , Residuos Industriales/análisis , Trametes/química , Trametes/crecimiento & desarrollo , Trametes/metabolismoRESUMEN
The effects of repeated atrazine application (40 mg a.i.kg(-1)) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show a lag phase. Microbial enzyme activities were reduced significantly with atrazine application but rapidly recovered. Microbial diversity obtained by BiologEcoplate was similar after the first and second atrazine application. However, an inhibitory effect was observed after the third application. After each atrazine application, culturable fungi were reduced, but rapidly recovered without significant changes in culturable bacteria and actinomycetes compared to the control. Denaturing gradient gel electrophoresis (DGGE) patterns demonstrated that microbial community structure remained relatively stable in time when compared to the controls. In conclusion, our results demonstrated that after successive ATZ applications, the peat based biomixture had a good degradation capacity. Moreover, microbiological assays demonstrated the robustness of the peat based biomixture from a microbiological point of view to support pesticide degradation.
Asunto(s)
Atrazina/análisis , Atrazina/química , Consorcios Microbianos/efectos de los fármacos , Microbiología del Suelo , Contaminantes del Suelo/análisis , Actinobacteria/clasificación , Actinobacteria/efectos de los fármacos , Bacterias/clasificación , Bacterias/efectos de los fármacos , Biodegradación Ambiental , Electroforesis en Gel de Gradiente Desnaturalizante , Hongos/clasificación , Hongos/efectos de los fármacos , Plaguicidas/química , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Suelo , Contaminantes del Suelo/metabolismo , Factores de TiempoRESUMEN
The effect of the terpenes α-pinene, eucalyptol, and limonene, individually and as mixtures, on atrazine (ATZ) biodegradation and on biological activity in a biobed biomixture was evaluated. Additionally, terpenes emitted from the biomixture were captured using solid-phase microextraction. Terpenes added individually at relatively low concentrations (50 µg kg(-1)) significantly enhanced ATZ degradation and biological activity during the first incubation days. No significant effect on ATZ degradation was found from adding the terpene mixture, and, interestingly, an inhibitory effect on phenoloxidase activity was found during the first 20 days of incubation when mixed terpenes were present at 100 µg kg(-1). Capturing terpenes demonstrated that during the first hour of incubation a significant fraction of the terpenes was volatilized. These results are the first to demonstrate the feasibility of using terpenes to enhance the degradation of a pesticide. However, successive applications of terpenes or the addition of materials that slowly release terpenes could sustain the ATZ degradation enhancement.
Asunto(s)
Atrazina/metabolismo , Reactores Biológicos/microbiología , Compuestos Orgánicos Volátiles/metabolismo , Biodegradación Ambiental , Cromatografía Líquida de Alta Presión , Fluoresceínas/metabolismo , Semivida , Hidrólisis , Monofenol Monooxigenasa/metabolismo , Terpenos , VolatilizaciónRESUMEN
Six new species of the doryctinae wasp genus Hecabolus Curtis 1834 (Braconidae) are described from Brazil and Venezuela: H. assis sp. nov., H. julianoi sp. nov., H. robustus sp. nov., H. seniaridus sp. nov., H. shimborii sp. nov., and H. sulmatogrossensis sp. nov. A key to the nine described species of Hecabolus is provided.
Asunto(s)
Avispas/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Femenino , Masculino , Tamaño de los Órganos , América del Sur , Avispas/anatomía & histología , Avispas/crecimiento & desarrolloRESUMEN
Atrazine is a commonly used herbicide for maize production in Chile, but it has recently been shown to be ineffective in soils that receive applications of cow slurries generated from the dairy industry. This effect may be caused either by the sorption of the pesticide to organic matter or more rapid degradation in slurry-amended soils. The objectives of this study were to evaluate the effects of cow slurry on atrazine dissipation, the formation of atrazine metabolites and the modification of bacterial community in Andisol. The cow slurry was applied at doses of 100,000-300,000 Lha(-1). After 4 weeks, atrazine was applied to the slurry-amended soils at concentrations of 1-3 mg kg(-1). The amounts of atrazine and its metabolites were determined by high performance liquid chromatography (HPLC). The soil microbial community was monitored by measurement of CO(2) evolution and changes in bacterial community using PCR-DGGE of 16S rRNA genes. The results show that cow slurry applications had no effect on atrazine dissipation, which had a half-life of 15-19 days. The atrazine metabolites were detected after 20 days and were significantly higher in soils amended with the slurry at both 20 and 40 days after application of the herbicide. Respiration rates were elevated after 10 days in all soils with atrazine addition. Both the atrazine and slurry amendments altered the bacterial community structures, indicated by the appearance of specific bands in the DGGE gels after 10 days. Cloning and sequencing of the 16S rRNA genes from the DGGE gels showed that the bands represented various genera of beta-proteobacteria that appeared in response to atrazine. According to our results, further field studies are required to explain the lower effectiveness of atrazine in weed control. These studies may include the effect of dissolved organic carbon on the atrazine mobility.