The influence of different nutrients on biosurfactant production by Rhodococcus erythropolis was investigated. Increasing the concentration of phosphate buffer from 30 up through 150 mmol/L stimulated an increase in biosurfactant production, which reached a maximum concentration of 285 mg/L in shaken flasks. Statistical analysis showed that glycerol, NaNO 3 , MgSO 4 and yeast extract had significant effects on production. The results were confirmed in a batchwise bioreactor, and semi-growth-associated production was detected. Reduction in the surface tension, which indicates the presence of biosurfactant, reached a value of 38 mN/m at the end of 35 hours. Use of the produced biosurfactant for washing crude oilcontaminated soil showed that 2 and 4 times the critical micellar concentration (CMC) were able to remove 97 and 99% of the oil, respectively, after 1 month of impregnation.

Cryptosporidium is an emergent pathogen that causes profuse diarrhea in humans. Outbreaks of human cryptosporidiosis have implicated water as a possible source of contamination. In this study the presence of Cryptosporidium sp. oocysts was investigated as well as the fecal contamination in groundwater for consumption in Itaquaquecetuba São Paulo. Therefore, it was possible to notice that the septic tanks were located close to the wells, exposing them to risk of contamination. As a consequence of these results and observations efficient disinfecting practices and groundwater monitoring are recommended.

The production of biosurfactant by Rhodococcus erythropolis during the growth on glycerol was investigated. The process was carried out at 28°C in a 1.5-L bioreactor using glycerol as carbon source. The bioprocess was monitored through measurements of biosurfactant concentration and glycerol consumption. After 51 h of cultivation, 1.7 g/L of biosurfactant, surface, and interfacial tensions values (with n-hexadecane) of 43 and 15 mN/m, respectively, 67% of Emulsifying Index (E24), and 94% of oil removal were obtained. The use of glycerol rather than what happens with hydrophobic carbon source allowed the release of the biosurfactant, originally associated to the cell wall.

Human activity in the Antarctic requires the use of petroleum hydrocarbons as the main energy source for a variety of operations. In the current study, in situ soil microcosms were constructed in the proximity of the Brazilian Antarctic Station Comandante Ferraz, King George Island, South Shetland Islands, to analyse the effect of oil amendment on the indigenous bacterial community in contaminated and uncontaminated sites to assess the potential for bioremediation. Microcosms were sampled for heterotrophic and hydrocarbon-degrader bacterial counts, pH, temperature, moisture, nutrient levels and petroleum hydrocarbons. Total organic carbon, nitrogen and phosphorus contents were generally low in the Antarctic cryosols. According to statistical analysis based on Colony Forming Unit numbers, significant bacterial populations were present in all microcosms, with larger numbers observed in oil amended than in nonamended soils. Aliphatic and aromatic fractions of diesel fuel were detected in the soil microcosms, and significant quantities were removed during the experiment. These results strongly suggest that the coldadapted bacterial community present in soils around the Brazilian Antarctic station has the potential to adapt and utilize the oil as a carbon source. This knowledge can contribute both to bioremediation technology and the goals of the the Antarctic Treaty which prohibits the introduction of foreign organisms into the region.

The production of biosurfactant by Rhodococcus erythropolis during the growth on glycerol was investigated. The process was carried out at 28 degrees C in a 1.5-L bioreactor using glycerol as carbon source. The bioprocess was monitored through measurements of biosurfactant concentration and glycerol consumption. After 51 h of cultivation, 1.7 g/L of biosurfactant, surface, and interfacial tensions values (with n-hexadecane) of 43 and 15 mN/m, respectively, 67% of Emulsifying Index (E24), and 94% of oil removal were obtained. The use of glycerol rather than what happens with hydrophobic carbon source allowed the release of the biosurfactant, originally associated to the cell wall.