Abstract This work aimed to evaluate the production of lipolytic complexes, produced by microorganisms isolated from a biological treatment system of effluents from a hotel. To select the best lipolytic microorganism for use in biotechnological processes, we tested 45 bacterial isolates recovered from the raw effluent of the hotel’s restaurant waste tank. Lipase production was assayed in culture medium supplemented with olive oil and rhodamine B, incubated at 25 °C and 30 °C for 24 h - 48 h. Results showed 22 isolates lipase producers. All isolates were inoculated on medium without yeast extract to select the ones with highest enzyme yields. Out of these, nine isolates showed high lipase activity. The strain with the larger halo was assayed in submerged culture using an orbital shaker and a bioreactor, with three different substrates (olive oil, grape seed oil, and canola oil). Isolate G40 identified as Acinetobacter baylyi was selected to run the production assays because it showed the best result in the solid medium. In the bioreactor, maximum lipase production was obtained after 12 h of culture with the three substrates evaluated: 0,358 U/mL.min-1 in olive oil, 0,352 U/mL.min-1 with grapeseed oil, and 0,348 U/mL.min-1 with canola oil.

RESUMO Nas terras baixas do Rio Grande do Sul, a sistematização é realizada, na maioria das vezes, sem declividade com o objetivo de cultivar arroz. Neste ambiente, são predominantes solos com baixa condutividade hidráulica devido à presença de um horizonte B, praticamente impermeável, perto da superfície. Depois da sistematização, por causa da acomodação do solo são formadas depressões onde se acumula água após a ocorrência de fortes chuvas, causando problemas nas culturas implantadas em sucessão ao arroz, como é o caso da soja. Objetivou-se neste trabalho quantificar áreas e volumes de acumulação de água, em função da declividade da sistematização. Foram estudadas cinco áreas sistematizadas típicas de terras baixas. As áreas originais apresentaram declividades de 0, 0,20, 0,25, 0,28 e 0,40%, sendo que a partir delas foram gerados os novos modelos digitais de elevação com declividades entre 0 e 0,5%. Através dos novos modelos gerados foram mapeadas as depressões com armazenamento superficial de água. A sistematização com declividades maiores que 0,1% são recomendadas para minimizar problemas com armazenamento superficial de água em áreas cultivadas com arroz.

ABSTRACT In the lowlands of Rio Grande do Sul, land leveling is mostly carried out with no slope for the purpose of rice production. In this environment, soils with a low hydraulic conductivity are predominant owing to the presence of a practically impermeable B-horizon near the surface. Land leveling leads to soil accommodation resulting in the formation of depressions where water accumulates after heavy rainfalls, subsequently leading to problems with crops implanted in succession to rice, such as soybeans. The objective of this research was to quantify the areas and volumes of water accumulation in soil as a function of the slope of land leveling. Five typical leveled lowland areas were studied as a part of this research. The original areas presented slopes of 0, 0.20, 0.25, 0.28 and 0.40%, which were used to generate new digital elevation models with slopes between 0 and 0.5%. These newly generated digital models were used to map the depressions with surface water storage. In conclusion, land leveling with slopes higher than 0.1% is recommended to minimize problems with superficial water storage in rice fields.

Spot blotch disease, caused by Bipolaris sorokiniana, is one of the major diseases of wheat and is responsible for large losses of wheat crops worldwide. We used polymerase chain reaction (PCR) with universal rice primers (URP) for molecular characterization of 60 monosporic B. sorokiniana isolates from Brazil and other countries, and evaluated the diversity of the samples. PCR amplification generated 232 different DNA fragments ranging in size from 100 to 2018 bp. The primers URP-4R, URP-2R, and URP-1F generated greater numbers of amplified fragments (36, 30, and 25, respectively) from the single-spore isolates, and some diversity was observed among the isolates generated using these primers. The primers URP-2F, URP-6R, URP-17R, URP-30F, and URP-38F produced a pattern of monomorphic fragments and 73% of the isolates showed an average of 44 different DNA-amplified fragments. Primer URP-2F generated a 578-bp fragment that was common to 83.7% of the isolates; primer URP-6R generated a 548-bp fragment and primer URP-38F generated a 650bp product that was common to 89.1% and 80% of the isolates, respectively. The URP-PCR primers provided important information about the genetic profiles of the monosporic cultures, which showed intraspecific variability among the monoconidial isolates and among the monosporic cultures that originated from the same polysporic strain. Our results indicate that URP's are sensitive and give reproducible results for assaying the genetic variability of B. sorokiniana.