Bioremediation in marine sediments with Bacillus strain selected in samples from forest soil

Abstract

Bacillus are a Gram positive bacteria developing high capability of degrading aromatic compounds. By using selective culture media with benzoic acid 5mM as carbon source, thirteen strains of Bacillus were selected in samples from Floresta da Tijuca soil (22' 50' S and 43' 15' W). Samples of marine sediments from Angra dos Reis (23' 30' S and 44' 25' W) were collected and examined for oil mixtures (0.33; 1.54 and 1.78%). The rate of oil mineralization in the marine sediments by the autochthonous microbial communities were 3; 1.65 and 0.8% of CO₂ per hour to 0.33; 1.54 and 1. 78% of oil, respectively. When the samples were inoculated with Bacillus strain, the degree of oil mineralization increased 4.65; 3.4 and 2% of CO₂ per hour to 0.33; 1.54 and 1.78% of oil, respectively. These results show that the presence of Bacillus strain increased the CO₂ production 2.5 folds in sediments with 1.78% of oil, 2 folds in sediments with 1.54% of oil and 1.5 folds in sediments with 0.33% of oil content. The autochthonous microbial communities have a slow response to oil. However, the inoculation of a adapted Bacillus strain is sufficient to induce an increase in the oil degradation