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Acosta-Rodriguez I.,Autonomous University of San Luis Potosi | Acosta-Rodriguez I.,Laboratory Of Micologia Experimental | Moctezuma-Zarate M.G.,Autonomous University of San Luis Potosi | Moctezuma-Zarate M.G.,Laboratory Of Micologia Experimental | And 4 more authors.
Informacion Tecnologica | Year: 2011

Different microorganisms were isolated from various rivers of the Huasteca Potosina, in Mexico that grow in the presence of petroleum as the sole carbon source. The activity of alcohol oxidase was determined by a colorimetric method. The most common bacteria present in the samples were Pseudomonas aeruginosa (50%) and only one type of yeast was found, Candida albicans (6.25%). Furthermore, they show good activity of alcohol oxidase in the cytosolic fraction with different substrates. It was concluded that this microorganisms could be used for decontamination of aquatic habitats polluted with petroleum.

Levin L.,Laboratory Of Micologia Experimental | Melignani E.,Laboratory Of Micologia Experimental | Ramos A.M.,Laboratory Of Micologia Experimental
Bioresource Technology | Year: 2010

The effect of amino acids, complex nitrogen sources and vitamin addition on Trametes trogii, Trametes villosa and Coriolus versicolor var. antarcticus ligninolytic enzyme production, was evaluated. Dye decolorization by their culture filtrates was compared. Glutamic acid followed by peptone, were the best N sources for laccase and manganese peroxidase production. The three fungi produced two laccase isoenzymes (molecular weights from 38 up to 150 kDa); their pattern of production was not affected by medium composition. Although the response was not uniform, vitamin addition sometimes stimulated ligninolytic enzyme production, but never inhibited it. Thiamine induced manganese peroxidase production. T. trogii grown in glutamic acid produced culture filtrates with the highest laccase (188.3 U/ml) and manganese peroxidase activities (4.5 U/ml), rendering the best results in decolorization. These crude filtrates were able to decolorize in half hour (at pH 4.5, 30 °C): 13%, 23%, 40%, 46%, 82%, 94% and 95% of Gentian Violet, Xylidine, Congo Red, Malachite Green, Remazol Brilliant Blue R, Indigo Carmine and Anthraquinone Blue, respectively. © 2010 Elsevier Ltd. All rights reserved.

Da Re V.,Laboratory Of Micologia Experimental | Papinutti L.,Laboratory Of Micologia Experimental | Forchiassin F.,Laboratory Of Micologia Experimental | Levin L.,Laboratory Of Micologia Experimental
Enzyme and Microbial Technology | Year: 2010

Loblolly pine kraft pulp was bleached in a totally chlorine-free sequence that involved treatment with culture supernatants from the white-rot fungus Trametes trogii followed by a peroxide stage. The whole process was performed at 28 °C, and did not require mediator addition in the enzymatic stage. Different operating conditions in the peroxide stage (pH, peroxide concentration and treatment time), were tested by using response surface methodology based on a Doehlert experimental design, in order to describe their effects and normalize a biobleaching protocol. The results showed that all three independent variables had significant effect on the luminance (L*) and Chroma (C*) of the enzyme-treated pulp. Best results were obtained after 1 h of enzyme incubation (352 U laccase, 2 U Mn-peroxidase per g of oven-dry pulp), followed by 96 h treatment with 2.5% hydrogen peroxide in sodium succinate buffer pH 6 (5% consistency). We obtained a noteworthy increase in L* = 94.45 (compared with 94.5 of the white reference standard (titanium oxide), 69.94 of the initial pulp, and 83.11 of the peroxide-bleached control), a decrease in C* (9.85), with minor pulp yield loss (less than 5%), under essentially mild conditions, using a low-cost source of enzyme. © 2009 Elsevier Inc. All rights reserved.

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