INOCULAÇÃO DE SUBSTRATO COLONIZADO COMO ALTERNATIVA AOS PEQUENOS PRODUTORES DE COGUMELOS COMESTÍVEIS NO BRASIL

A produção de cogumelos comestíveis do gênero Pleurotus sp., popularmente conhecidos como shimeji, é amplamente difundida no Brasil, em virtude da facilidade de cultivo e de suas propriedades nutricionais. Como decompositor primário, promovem a ciclagem de nutrientes oriundos de resíduos diversos. Pequenos produtores devem se adequar a requisitos para alcançar boa produtividade, em especial, substrato de boa qualidade e acessível, e fonte de inóculo vigoroso que supra as demandas. O objetivo dessa pesquisa é avaliar a viabilidade na produção de cogumelos a partir de composto inoculado com alíquota de outro composto previamente colonizado por micélio, comparada com o método tradicional de inoculação (“spawn”). Os dois sistemas de inoculação foram comparados quanto à velocidade de colonização do composto e produtividade, em gramas de cogumelo colhido. Os resultados não mostraram diferença estatística entre os dois experimentos, apontando alternativa sustentável e viável na substituição de inóculo aos pequenos produtores, especialmente na indisponibilidade do inóculo comercial. É, portanto, uma alternativa que viabiliza o ciclo agroecológico na propriedade rural, tornando, inclusive, a produção de cogumelos comestíveis mais rentável e menos onerosa ao pequeno produtor

Microbial activity in two soils with different clay content contaminated by different diesel/biodiesel mixtures

Biodiesel is an alternative energy source that has a high biodegradability potential and low toxicity, contributing to ecosystem impact reductions. The aim of this study was to determine, by the natural attenuation technique, the microbial activity of two soils: one clayey (CLA) and the other sandy (SAN), contaminated with different concentrations of biodiesel blended with diesel (B0, B5, B20 and B100) simulating a surface spill. The respirometry, fluorescein diacetate (FDA) hydrolysis and cultivable heterotrophic bacteria and actinobacteria count techniques were used to determine the microbial activity in the different microcosms at up to 48 days of incubation. For the respiration activity, the CLA soil was most active at all mixed fuel concentrations (B0, B5, B20 and B100), as compared to the SAN. Furthermore, the biodiesel addition to the two soil types contributed to the microbial activity increase, and higher CO2 release values were found in the B20 and B100. For the FDA activity, it was found that the CLA soil showed higher activity at the B5 and B20 concentrations, and heterotrophic count showed a tendency towards a CFU g-1 decrease as the incubation time increased. This indicates that the CLA soil, due to a higher amount of nutrients, clay, organic matter and CEC, was associated with the addition of biodiesel and showed higher microbial activity. The results obtained in this study contribute to future studies of surface contamination by different mixtures of diesel/biodiesel in soils with similar physical and chemical characteristics

Purification and characterization of a thermostable alkaline cellulase produced by Bacillus licheniformis 380 isolated from compost

During composting processes, the degradation of organic waste is accomplished and driven by a succession of microbial populations exhibiting a broad range of functional competencies. A total of 183 bacteria, isolated from a composting process, were evaluated for cellulase activity at different temperatures (37, 50, 60, and 70°C) and pH values. Out of the 22 isolates that showed activity, isolate 380 showed the highest cellulase activity. Its ability to produce cellulase was evaluated in culture medium supplemented with carboxymethyl cellulose, microcrystalline cellulose, wheat straw, and rice husk. The culture medium supplemented with carboxymethyl cellulose induced higher enzyme activity after 6 hours of incubation (0.12 UEA mL-1 min-1). For wheat straw and rice husk, the results were 0.08 UEA mL-1 min-1 for both, while for microcrystalline cellulose, 0.04 UEA mL-1 min-1 were observed. The highest carboxymethyl cellulase activity was observed at 60°C (0.14 UEA mL-1 min-1) for both crude and partially purified enzyme after 30 and 120 min of incubation, respectively. Alkalinization of the medium was observed during cultivation in all substrates. The cellulase had a molecular mass of 20 kDa determined by SDS-Page. Isolate 380 was identified as Bacillus licheniformis. This work provides a basis for further studies on composting optimization

Simulation of a surface spill of different diesel/biodiesel mixtures in an ultisol, using natural attenuation and bioaugmentation/biostimulation

Accidents caused by leaks and/or spills on soils need to be addressed. Natural attenuation, biostimulation and bioaugmentation can be useful bioremediation strategies for decontamination processes in soils of diesel/ biodiesel mixtures. The purpose of this study was to evaluate the degradation rate of the different fuels (B0, B20 and B100) in an ultisol under natural attenuation and biostimulation/bioaugmentation during 60 days of incubation in a controlled microcosm simulating a surface spill over soil. The degradation of different diesel/biodiesel mixtures was monitored for up to 60 days by dehydrogenase activity, respirometry by CO2 release, the most probable number of heterotrophic and degrading microorganism and gas chromatography. The bacterial inoculum employed for biostimulation/bioaugmentation strategy consisted of Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The two bioremediation strategies have showed great degradation rates. The natural attenuation was effective for B0 and B20 treatments. The addition of the bacterial consortium and macronutrients contributed to the increased degradation of pure biodiesel in relation to natural attenuation, with higher rates for CO2 release, enzymatic and degrading activity. It is suggested that the bacterial consortium has proven effective for presenting significant values for such parameters until the end of the 60-day incubation period

Reversión de los efectos de la historia de incontrolabilidad bajo contingencias de variación comportamental

A exposição a eventos incontroláveis produz dificuldade na aprendizagem de novos comportamentos. O presente estudo investigou o papel da instrução e da exposição à controlabilidade na reversão dos efeitos da história de incontrolabilidade. No treino, estudantes universitários foram expostos à controlabilidade (grupo CC) ou à incontrolabilidade (grupos IC, ICi, II, IIi). Na "terapia", os grupos CC, IC e ICi foram expostos à controlabilidade, enquanto os grupos II e IIi continuaram expostos à incontrolabilidade. Os grupos ICi e IIi receberam uma instrução de incontrolabilidade/controlabilidade. No teste, todos os grupos foram expostos a controlabilidade. Os participantes expostos apenas à incontrolabilidade (grupos II e IIi) apresentaram maior persistência do responder do que aqueles expostos à "terapia" (grupos IC e ICi), os quais não diferiram dos participantes expostos apenas à controlabilidade (Grupo CC), a despeito da instrução. O procedimento de "terapia", portanto, foi mais efetivo do que a instrução para reverter os efeitos da história de incontrolabilidade.Pre-exposure to uncontrollable events interferes with subsequent learning of new behaviors. The present study investigated the role of instructions and of the exposure to controllability in reversing the effects of a history of uncontrollability. During training, college students were exposed to controllability (CC Group) or to uncontrollability (IC, ICi, II and Iii groups). During "therapy", the CC, IC and ICi groups were exposed to controllability while the II and IIi groups remained exposed to uncontrollability. An instruction on uncontrollability/controllability was given to the ICi and IIi groups. During testing, all groups were exposed to controllability. The participants exposed only to uncontrollability (II and IIi groups) showed greater response persistence than those exposed to "therapy" (IC and ICi groups) that did not differ from those exposed only to controllability (CC Group). The "therapy" procedure, then, was more effective than instructions in reversing the effects of a history of uncontrollability.La exposición a eventos incontrolables produce dificultad en el aprendizaje de nuevos comportamientos. El presente estudio investigó el rol de la instrucción y de la exposición a la controlabilidad en la reversión de los efectos de la historia de incontrolabilidad. En el entrenamiento, estudiantes universitarios fueron expuestos a la controlabilidad (grupo CC) o a la incontrolabilidad (grupos IC, ICi, II, IIi). En la "terapia", los grupos CC, IC y ICi fueron expuestos a la controlabilidad, mientras que los grupos II y IIi siguieron expuestos a la incontrolabilidad. Los grupos ICi y IIi recibieron una instrucción de incontrolabilidad/controlabilidad. En el test, todos los grupos fueron expuestos a la controlabilidad. Los participantes expuestos sólo a la incontrolabilidad (grupos II y IIi) presentaron mayor persistencia del responder, comparados a aquellos expuestos a la "terapia" (grupos IC y ICi), los cuales no se distinguieron de los participantes expuestos sólo a la controlabilidad (Grupo CC), pese a la instrucción. El procedimiento de "terapia", por lo tanto, fue más efectivo que la instrucción para revertir los efectos de la historia de incontrolabilidad