Pre-screening of filamentous fungi isolated from a contaminated site in Southern Brazil for bioaugmentation purposes

Four Aspergillus sp. strains were isolated from contaminated soil in Rio Grande, Southern Brazil. The biodegradation potential of these strains was evaluated using a simple method involving the determination of colony growth rates on plates containing a specific hydrocarbon or petroleumderivative as the only carbon source. The LEBM1 strain presented a high tolerance level to BTX. It was the only strain capable of growth on all the media, with growth rates varying from 1.3 to 2.2 mm/day. The LEBM2 strain presented the potential for phenol degradation, while the LEBM3 strain could be used for gasoline, diesel oil, hexane and chlorobenzene

Different cell disruption methods for astaxanthin recovery by Phaffia rhodozyma

Astaxanthin (3,3'-dihydroxy-b,b'-carotene-4,4'-dione) is carotenoid of high market value whose demand has increased in such fields as aquaculture, pharmaceutical supplements and natural coloring. Cell disruption is the first step for isolating intracellular materials and it depends on the cell wall permeability. In order to maximize the  recovery of astaxanthin from Phaffia rhodozyma NRRL-Y17268, drying and freeze pretreatments were tested by different cell disruption methods: abrasion with celite, glass pearls in vortex agitator, ultrasonic waves, sodium  carbonate (Na2CO3) and dimethyl sulfoxide (DMSO). The method with Na2CO3 was not effective; meanwhile, the agitator with glass pearls, the abrasion with celite and the ultrasonic waves were found as promising for future  studies. As a result, the DMSO in freeze-dried biomass with 4 process cycles and biomass/DMSO relation of 0.025 g/ml was found to be the most efficient for analytical determination, increasing about up to 25 times the astaxanthin recovery.Key words: Carotenoids, yeast, chemical disruption, dimethyl sulfoxide