A adoção de práticas conservacionistas alteram as propriedades físicas, químicas e biológicas do solo, influenciando a composição da comunidade microbiana. O trabalho objetivou obter informação sobre a qualidade, diversidade e atividade biológica do solo, quando submetido a dois tipos de manejo do solo (plantio direto escarificado (PDE) e não escarificado (PDNE) e três tipos de manejo de cobertura (Sucessão: soja-trigo, Rotação I: soja-nabo+trigo/soja-aveia+ervilhaca/ e Rotação II: soja-aveia+ervilhaca+nabo/milho-crotalária juncea-trigo/soja). Foram analisadas a biomassa microbiana, atividade enzimática, taxa de respiração basal e diversidade genética do solo, nos períodos do verão (fevereiro/2016) e inverno (setembro/2016). O carbono e nitrogênio da biomassa microbiana foram superiores nos tratamentos sob PDNE. Todas as enzimas apresentaram incremento na atividade no período do verão. Para a respiração basal dos microrganismos, a menor taxa de CO2 acumulada foi no período do verão em solo sob PDNE. Detectou-se variabilidade genética através da técnica de Random amplified polymorphic DNA (RAPD), reunindo os tratamentos em quatro grupos. Pode-se concluir que o sistema PDNE associado à rotação de culturas contribui para aumentar a biomassa microbiana e atividade enzimática no solo. Além disso, a técnica de RAPD associada a outros bioindicadores tornam-se importantes ferramentas para o monitoramento da qualidade do solo.

The adoption of conservation practices affect the physical, chemical and biological properties of the soil, altering the composition of the microbial community. The objective of this research was to obtain information about the soil quality, diversity and biological activity, of the soil when submitted to two types of soil management (scarified (PDE) and no-scarified tillage (PDNE)) and three types of cover management (Succession: soybean-wheat, Rotation I: Soybean-turnip+wheat/soybean-oats+vetch and Rotation II: soybean-oats+vetch+turnip/corn-crotalaria juncea-wheat/soybeans). The microbial biomass, enzymatic activity, basal respiration rate and soil genetic diversity were analyzed during the summer (february/2016) and winter (september/2016) periods. The carbon and nitrogen of the microbial biomass were higher in treatments under PDNE. All enzymes showed an increase in the activity during the summer period. For the basal respiration of the microorganisms, the smallest accumulated CO2 rate was in the summer period under PDNE. The RAPD technique proved to be efficient in the detection of genetic variability, combining treatments in four groups. We concluded that PDNE associated with crop rotation contributes to increase the levels of microbial biomass and soil enzymatic activity. In addition, the RAPD technique associated with other bioindicators become important tools for the monitoring and evaluation of soil quality.

Abstract One hundred fifty fungal strains were isolated from the Pampa biome for production of polyunsaturated fatty acids (PUFA). Microbial oil was produced by submerged cultivation at 120 rpm, 28 ºC for 7 days. Seven strains showed the best results for lipids accumulation, and they were selected in order to evaluate the influence of the temperature (15 and 28 ºC) on the lipid production and profile. The fungus Nigrospora sp. produced the highest lipid level: at 28 ºC were produced 11.28% of lipids and 51.94% of PUFA and at 15 ºC were produced 6.02% of lipids and 42.39% of PUFA. Plackett Burman design was performed to investigate the main effects of the temperature (15-25 ºC), pH (4.0-6.0), agitation (120-200 rpm), corn steep liquor (5-15% (v/v)) and sucrose concentrations (60-180 g L-1). The highest PUFA production (55.75%) was observed at the lowest temperatures (15 ºC), whereas the maximum lipid production was 5.54% at 25 ºC.

Abstract In this work the bioherbicide production from Phoma sp. by solid-state fermentation was optimized. Agroindustrial residues such as bagasse, soybean bran and corn steep liquor were used as substrate. The bioherbicide was extracted from the fermented solid and the supernatant was applied for the control of the target plant. The evaluated responses in the bioassay were plant height, root length, fresh and dry weight, number of flowers and phytotoxicity. The results in the bioassays demonstrated that the bioherbicide presented activity towards the target plant and the intensity of the effect was influenced by the formulation of the fermentation medium. The optimized condition for bioherbicide production was (wt%): moisture content 70.0, soybean bran content 30.0 and corn steep liquor (CSL) 20.0, it being possible to obtain an injury phytotoxicity level of 40. The bioherbicide showed a mode of action based on the inhibition of carotenoid biosynthesis.

As áreas de mineração de cobre podem apresentar teores elevados disponíveis deste nutriente no solo afetando o desenvolvimento vegetal. O objetivo do trabalho foi avaliar o efeito do óleo essencial de eucalipto na associação ectomicorrizica com o fungo Pisolithus microcarpus em mudas de bracatinga e seu comportamento em solo contaminado por cobre. O experimento foi conduzido em delineamento inteiramente casualizado em arranjo fatorial (4 x 5) sendo quatro formas de inoculação (testemunha, óleo, fungo e óleo + fungo) e cinco doses de cobre (nível natural do solo, 60, 120, 180 e 240 mg de Cu kg-1 de solo) com cinco repetições. Avaliaram-se a altura de plantas (cm), diâmetro do colo (mm), massa seca da parte aérea e radicular (g), comprimento radicular (cm), área superficial específica (cm²), relação altura/diâmetro do colo e índice de qualidade de Dickson. Verificou-se que a utilização de 40 μL L-1 de óleo essencial de eucalipto aumenta a altura das mudas de bracatinga em solo com adição de 180 mg de Cu kg-1 de solo. Não há efeito da inoculação de Pisolithus microcarpus no crescimento das mudas de bracatinga em solo contaminado com cobre. As doses de cobre reduzem a massa seca da parte aérea e radicular das mudas.

The copper mining areas may present elevated quantity available of this nutrient in the soil affecting the plant development. The objective of this research was to evaluate the effect of eucalyptus essential oil in the association of ectomycorrhizal with Pisolithus microcarpus fungus in bracatinga seedlings and its behavior in soil contaminated by copper. The experiment was conducted in a completely randomized delineation in a factorial arrangement (4 x 5), four types of inoculation (control, oil, fungus and oil + fungus) and five doses of copper (natural soil level, 60, 120, 180 and 240 mg of Cu kg-1 soil) were used with five repetitions. Plant height (cm), root collar diameter (mm), dry mass of shoot and root (g), root length (cm), specific surface area (cm²), and ratio of height/diameter of the collar and Dickson quality index were evaluated. It was verified that use of 40 μL L-1 of eucalyptus essential oil increases the bracatinga seedlings height in soil with addition 180 mg of Cu kg-1 soil. There is no effect of Pisolithus microcarpus inoculation in growth of bracatinga seedlings in soil contaminated with copper. The dose of copper reduces dry mass of shoot and root of seedlings.

Neste trabalho é apresentado um estudo a respeito da análise da estrutura de substâncias redutoras de tensão superficial produzidas por Pseudomonas citronellolis 222A estimulado pela presença de ferro. Esta bactéria foi isolada de um solo que há 17 anos vem sendo utilizado para o tratamento de borra oleosa proveniente da indústria petroquímica e de refinaria de petróleo. O espectro de massa difere do espectro de P. aeruginosa, indicando que as substâncias redutoras de tensão superficial produzidas por P. citronellolis podem ser um novo tipo de biosurfactante.

In this work we investigated the structure of the iron-stimulated surface tension reducing substances produced by P. citronellolis 222A isolated from a 17-years old landfarming used for sludge treatment in petrochemical industries and oil refinery. Its mass spectrum differs from P. aeruginosa spectrum, indicating that the surface tension reducing substances produced by P. citronellolis can be a new kind of biosurfactant.