BACKGROUND: Lipase production by Penicillium simplicissimum using soybean meal as substrate has been investigated. A factorial design technique was used to evaluate the effects of incubation temperature, initial moisture of the meal and substrate supplementation with low cost supplements, on lipase production. Soybean oil and wastewater from a slaughterhouse, which is rich on oil and fat, corn steep liquor and yeast hydrolysate, were tested as supplementary carbon and nitrogen sources.

Macroinvertebrados bentônicos são afetados pela alteração dos sistemas aquáticos, que diminuem ou aumentam sua população. O conhecimento sobre macroinvertebrados bentônicos pode ser utilizado para conhecer a qualidade da água de lagos e rios, pois estes organismos respondem às variações nas condições ambientais. O objetivo deste estudo foi utilizar a estrutura de comunidades de macroinvertebrados como indicador de qualidade ambiental em dois rios de abastecimento público no município de Erechim, Estado do Rio Grande do Sul. As coletas foram realizadas mensalmente de novembro de 2014 até abril de 2015, utilizando-se amostrador tipo Surber. Para a avaliação das condições ambientais foi aplicado um protocolo de avaliação rápida (PAR). Foram identificados 4.096 macroinvertebrados, distribuídos em 41 táxons de Annelida, Nematoda, Crustacea, Aracnida e Insecta. Os dois rios apresentaram trechos com alteração antrópica nas margens e os ambientes mais alterados foram associados com a maior abundância do grupo trófico coletor-catador. Integrar o método de avaliação da diversidade de habitats com análises da comunidade bentônica pode ser um método eficiente para obtenção de parâmetros mais completos da qualidade da água e da degradação dos sistemas aquáticos.

The production of lipases by Penicillium simplicissimum using solid-state fermentation and soy cake as substrate was investigated. The effects of temperature, cake moisture, and carbon supplementation on lipase production were studied using a two-level experimental plan. Moisture, pH, and lipase activity were followed during fermentation. Statistical analysis of the results was performed to evaluate the effect of the studied variables on the maximum lipase activity. Incubation temperature was the variable that most affected enzyme activity, showing a negative effect. Moisture and carbon supplementation presented a positive effect on activity. It was possible to obtain lipase activity as high as 21 U / g of dry cake in the studied range of process variables.

This study aimed to evaluate the waste cooking oil (WCO) hydrolysis in ultrasonic system using lipase as catalyst. Lipase was produced by the fungus Aspergillus niger via solid state fermentation (SSF) using canola meal as substrate. Prior to the hydrolysis reaction, the lipase behavior when subjected to ultrasound was evaluated by varying the temperature of the ultrasonic bath, the exposure time and the equipment power. Having optimized the treatment on ultrasound, the WCO hydrolysis reaction was carried out by evaluating the oil:water ratio and the lipase concentration. For a greater homogenization of the reaction medium, a mechanical stirrer at 170rpm was used. All steps were analyzed by experimental design technique. The lipase treatment in ultrasound generated an increase of about 320% in its hydrolytic activity using 50% of ultrasonic power for 25min. at 45°C. The results of the experimental design conducted for ultrasound-assisted hydrolysis showed that the best condition was using an oil:water ratio of 1:3 (v:v) and enzyme concentration of 15% (v/v), generating 62.67μmol/mL of free fatty acids (FFA) in 12h of reaction. Thus, the use of Aspergillus niger lipase as a catalyst for hydrolysis reaction of WCO can be considered as a possible pretreatment technique of the oil in order to accelerate its degradation.

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