Phenols are toxic pollutants found in industrial wastes imposing several risks to human health. Tyrosinase (EC 1.14.18.1) is an oxygenase oxyreductase found in several life forms, like the mushroom Agaricus bisporus. This enzyme is readily available from this fungal tissue leading to high activity extracts without extensive purification, thus suggesting its potential as a biocatalyst for applications involving biomodification of phenols or bioremediation of phenol-polluted waters. The purpose of this work was to employ a crude extract from the Agaricus bisporus mushroom and its biomass for the removal of phenol from polluted water. Experiments were carried out without pH control. The initial phenol concentration in all solutions was 100 mg l(-1). Four enzymatic concentrations (50, 100, 200 and 400 U ml(-1)) were tested. Reactions, with 200 U ml(-1) and 400 U ml(-1) enzymatic activity, led to 90% of phenol removal. Chitosan was used as a coagulant, but no significant improvement was observed. The in natura fungi was also able to remove 90% of phenol, demostrating its viability as a biocatalyst in bioremediation process.

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Drilling fluid has many functions, such as carry cuttings from the hole permitting their separation at the surface, cool and clean the bit, reduce friction between the drill pipe and wellbore, maintain the stability of the wellbore, and prevent the inflow of fluids from the wellbore and form a thin, low-permeable filter cake. Filter cake removal is an important step concerning both production and injection in wells, mainly concerning horizontal completion. The drilling fluids are typically comprised of starch, the most important component of the filter cake. A common approach to remove this filter cake is the use of acid solutions. However, these are non-specific reactants. A possible alternative is the use of enzymatic preparations, like amylases, that are able to hydrolyze starch. Wells usually operate in drastic conditions for enzymatic preparations, such as high temperature, high salt concentration, and high pressure. Thus, the main objective of this work was to characterize four enzymatic preparations for filter cake removal under open hole conditions. The results showed that high salt concentrations (204,000 ppm NaCl) in completion fluid decreased amylolytic activity. All enzymatic preparations were able to catalyze starch hydrolysis at all temperatures tested (30, 65, 80, and 95 degrees C). An increase of amylolytic activity was observed with the increase of pressure (100, 500 and 1,000 psi) for one commercial amylase.

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