In this study solid and liquid wastes from the olive oil processing industry were evaluated as substrates for Yarrowia lipolytica growth with the aim of lipase production. Olive mill wastewater and olive oil cake seemed to provide necessary nutrients and physical support for the yeast to grow and produce enzyme. The highest lipolytic activity of 850 IU dm-3 was achieved after 4 days of submerged cultivation in supplemented olive mill wastewater. In addition, olive oil cake appeared to be a convenient substrate for lipase production under solid state fermentation mode. Lipase production was further improved by media supplementation and/or change in physical settings of the experiment. However, the most significant improvement of lipase production under solid state fermentation was achieved by an alkaline treatment of the substrate (more than 10-fold) when the amount of produced lipase reached up to ~40 IU g-1 of substrate. [Projekat Ministarstva nauke Republike Srbije, br. E!6750 i br. III 46010

The problem of environmental pollution becomes more worrisome day by day, primarily due to the large amounts of wastewater contaminated with various harmful organic compounds, discharged untreated or partially clean into the environment. Feasibility of use of horseradish peroxidase (Amoracia rusticana) in the synthetic dyes decolorization was approved by many researchers. Among a number of supports used for the immobilization, it was found that natural clay, kaolin, has excellent features which are a precondition for obtaining biocatalysts with the excellent performances. For this reason, a horseradish peroxidase was immobilized onto kaolin using glutaraldehyde as a cross-linking agent. Obtained biocatalyst was applied in the decolorization of anthraquinone dye C.I. acid violet 109. Under determined optimal conditions (pH 4.0, hydrogen peroxide concentration 0.6 mM, dye concentration 30 mg L-1 , temperature 24 °C) around 76% of dye decolorization was achieved. Reusability study showed that resulting biocatalyst was possible to apply four times in the desired reaction with relatively high decolorization percentage.

Enzymes produced by indigenous Pseudomonas aeruginosa strain have been subjected to research considering their potential application as detergent additives. As previously noted, lipase produced by Pseudomonas aeruginosa is highly alkaline, thermostable and solvent tolerant. Furthermore, same strain exhibits both lipase and protease activity establishing this lipase as potentially desirable component of enzyme-containing detergents. Further research was carried out to investigate insusceptibility of this lipase against coexisting native protease, several commercial surfactants, oxidizing agents and commercial detergents. Lipases and proteases remained highly active when incubated with several different surfactants and oxidizing agents under washing conditions. Moreover, presence of surfactants and oxidizing agents such as Tween® 20 and Triton® X-100 initially augment lipase and protease activity. Additionally, crude lipase preparation was insusceptible to coexisting native protease hence indicating possible storage stability. Overall, the remarkable properties of these enzymes make them potential detergent additives

Pseudomonas aeruginosa was repeatedly reported as powerful producer of rhamnolipid biosurfactants as well as producer of hydrolytic enzymes. In this study effects of four fermentation factors were evaluated using response surface methodology and experiments were performed in accordance with a four-factor and five-level central composite experimental design. Investigated factors were: fermentation temperature, time of fermentation, concentration of sunflower oil and concentration of Tween® 80. The most important finding was that regression coefficients of the highest values were those that describe interactions between factors and that they differ for lipase and rhamnolipid production, which were both investigated in this study. Production of both metabolites was optimized and response equations were obtained, making it possible to predict rhamnolipid concentration or lipase activity from known values of the four factors. The highest achieved rhamnolipid concentration and lipase activity were 138 mg dm-3 (sunflower oil concentration 0.8 %, Tween® 80 concentration 0.05 %, temperature 30°C, and fermentation time 72 h) and 11111 IU dm-3(sunflower concentration of 0.4 %, Tween® 80 concentration of 0.05 %, temperature of 30°C, and fermentation time of 120 h), respectively. [Projekat Ministarstva nauke Republike Srbije, br. E!6750 and br. III 46010