부산대학교 도서관

This study aimed at isolation of phenol degrading bacteria from olive mill wastes in Palestine. The efficiency of phenol removal and factors affecting phenol degradation were investigated. A bacterial strain (J20) was isolated from solid olive mill waste and identified asBacillus thuringiensisbased on standard morphological, biochemical characteristics and 16SrRNA sequence analysis. The strain was able to grow in a phenol concentration of 700 mg/L as the sole carbon and energy source. The culture conditions showed a significant impact on the ability of these cells to remove phenol. This strain exhibited optimum phenol degradation performance at pH 6.57 and 30 °C . Under the optimized conditions, this strain could degrade 88.6% of phenol (700 mg/L) within 96 h when the initial cell density was OD6000.2. However, the degradation efficiency could be improved from about 88% to nearly 99% by increasing the cell density. Immobilization of J20 was carried out using 4% sodium alginate. Phenol degradation efficiency of the immobilized cells of J20 was higher than that of the free cells, 100% versus 88.6% of 700 mg/L of phenol in 120 h, indicating the improved tolerance of the immobilized cells toward phenol toxicity. The J20 was used in detoxifying crude OMWW, phenolic compounds levels were reduced by 61% compared to untreated OMWW after five days of treatment. Hence,B. thuringiensis-J20 can be effectively used for bioremediation of phenol-contaminated sites in Palestine. These findings may lead to new biotechnological applications for the degradation of phenol, related to olive oil production. [ABSTRACT FROM AUTHOR]