ABSTRACT
Enzimas extracelulares de fungos são importantes para sua sobrevivência em ambientes inóspitos, sendo capazes de degradar compostos recalcitrantes. Fungos filamentosos secretam hidrolases e fenoloxidases capazes de degradar complexos de estruturas aromáticas, como de alguns xenobióticos. O propósito deste trabalho foi testar diferentes corantes (Azul de Metileno, Azure B, Verde Malaquita e Cristal Violeta), em substituição ao composto Poly R478, no método de seleção de microrganismos degradadores de fenóis em meio sólido, além de comparar tal atividade de Micoflora isolada de efluentes de indústria sucroalcooleira com a de outros fungos adquiridos em coleção oficial. Os corantes testados revelaram-se ótimos substitutos do Poly R478. O isolado que apresentou atividade descolorante mais intenso do que a do diâmetro de seu crescimento (Cladosporium sp.) foi testado, então, em meio líquido frente a dois substratos naturais e um sintético (bagaço de cana, serragem de madeira e azul de metileno). Este removeu altas concentrações de glicídios redutores, proteínas e fenóis totais, além de reduzir a DQO em meio com serragem de madeira como substrato fenólico natural. Tal fungo, portanto, mostrou-se promissor para compor consórcios visando cometabolismo e biorremediação de efluentes nos quais há presença de compostos fenólicos ou outros recalcitrantes com estrutura semelhante à de lignina.
Extracellular enzymes of fungi are important for survival in inhospitable environments, as they are able to degrade recalcitrant compounds. Filamentous fungi secrete hydrolases and phenoloxidases that are capable of degrading complexes of aromatic structures, such as certain xenobiotics. The purpose of this study was to test different dyes (methylene blue, Azure B, Malachite Green and Crystal Violet), replacing the compound Poly R478 in the method of selection of phenol decomposer microorganisms in solid medium, and compare this activity of the mycoflora of effluents from sugar-alcohol industry, to the ones of other fungi acquired in official collection. The tested dyes proved to be excellent substitutes for Poly R478. The isolate that showed more intense decolorant activity than the diameter of its growth (Cladosporium sp.) was then tested on two natural and one synthetic substrate (sugarcane bagasse, sawing wood, and methylene blue) in liquid medium. This isolate removed high concentrations of reducing sugars, proteins and total phenols, and reduced the COD in medium containing sawdust as natural substrate of phenols. This fungus, therefore, seems promising to form consortia for co-metabolism and bioremediation of effluents in which there is a presence of phenolic or other recalcitrant compounds with similar structure to lignin.
Subject(s)
Biodegradation, Environmental , Industrial Effluents DisposalABSTRACT
Kraft mill effluent, due to its organic matter content and acute toxicity, must be treated. A primary treatment followed by a secondary treatment is the most common system. Aerated lagoon is also considered an effective biological treatment, although this technology has some drawbacks related with operation parameters and land extension space. Moreover, the recovery efficiency for micropollutants contained in kraft mill effluent is questioned due to the anoxic zone in the system. The goal of this work is to evaluate the performance of the aerated lagoon to remove stigmasterol contained in kraft mill effluents. Kraft mill effluent was treated by an aerated lagoon (AL), which was operated with three different stigmasterol load rates (SLR = 0.2, 0.6 and 1.1 mg/L x d) and a hydraulic retention time of 1 day. The ALs maximum Chemical Oxygen Demand (COD) removal was 65 percent, whereas the Biological Oxygen Demand (BOD5) was around 95 percent. The removal efficiency of stigmasterol removal was 96 percent when SLR 1.1 mg/L x d, although an accumulation of stigmasterol was detected for lower SLR.