A bioeletrorremediação (BER) usa corrente elétrica para estimular o catabolismo de poluentes ambientais, como derramamentos de petróleo. No entanto, a aplicação de corrente ao solo pode ter efeitos adversos sobre os microrganismos envolvidos na degradação do petróleo. Identificamos e avaliamos as capacidades de BER de uma cepa de Aspergillus niger obtida de solo contaminado com petróleo. Os esporos desta cepa foram imobilizados em esferas de alginato (2 g) foram misturados com 100 g de solo franco-arenoso contaminado com hexadecano e expostos a 5, 10 ou 15 mA de corrente contínua em uma célula de 200 cm3 com eletrodos de cobre. A concentração de hexadecano no solo foi medida por cromatografia gasosa. Mais de 94% do hexadecano foi removido do solo em 12 dias para as correntes testadas, e o A. niger cresceu para 6 x 106 UFC g-1 em 15 dias na corrente de 10 mA. A degradação máxima do hexadecano foi alcançada usando uma corrente de 10 mA por 20 dias, mas mais de 99% do hexadecano foi removido no quinto dia. Esses resultados sugerem que o uso de grânulos de alginato contendo esporos promove o crescimento e a biodegradação do petróleo de A. niger exposto a correntes elétricas.
Palavras-chave: Aspergillus; bioeletrorremediação; hexadecano; petróleo; solo
Bioelectroremediation (BER) uses electrical current to stimulate catabolism of environmental pollutants, such as petroleum spills. However, applying current to soil may have adverse effects on the microorganisms involved in petroleum degradation. We identify and evaluate the BER capabilities of a strain of Aspergillus niger obtained from petroleum-contaminated soil. Spores of this strain immobilized in alginate spheres (2 g) were mixed with 100 g of hexadecane-contaminated sandy loam soil and exposed to 5, 10, or 15 mA direct current in a 200 cm3 cell with copper electrodes. Soil hexadecane concentration was measured by gas chromatography. More than 94% of hexadecane was removed from the soil within 12 days for the currents tested, and the A. niger grew to 6 x106 CFU g-1 in 15 days at 10 mA current. The maximum hexadecane degradation was achieved using a 10-mA current for 20 days, but more than 99% of the hexadecane was removed by the fifth day. These results suggest that the use of spore-containing alginate beads promotes growth and petroleum biodegradation of A. niger exposed to electrical currents.
Keywords: Aspergillus; bioelectroremediation; hexadecane; petroleum; soil
Bioelectroremediation (BER) uses electrical current to stimulate catabolism of environmental pollutants, such as petroleum spills. However, applying current to soil may have adverse effects on the microorganisms involved in petroleum degradation. We identify and evaluate the BER capabilities of a strain of Aspergillus niger obtained from petroleum-contaminated soil. Spores of this strain immobilized in alginate spheres (2 g) were mixed with 100 g of hexadecane-contaminated sandy loam soil and exposed to 5, 10, or 15 mA direct current in a 200 cm3 cell with copper electrodes. Soil hexadecane concentration was measured by gas chromatography. More than 94% of hexadecane was removed from the soil within 12 days for the currents tested, and the A. niger grew to 6 x106 CFU g-1 in 15 days at 10 mA current. The maximum hexadecane degradation was achieved using a 10-mA current for 20 days, but more than 99% of the hexadecane was removed by the fifth day. These results suggest that the use of spore-containing alginate beads promotes growth and petroleum biodegradation of A. niger exposed to electrical currents.
Keywords: Aspergillus; bioelectroremediation; hexadecane; petroleum; soil
