Isolation and characterization of phenol degrading bacterium strain Bacillus thuringiensis J20 from olive waste in Palestine
Date
2017-10-05
Authors
Ereqat, Suheir I.
Abdelkader, Ahmad A.
Nasereddin, Abedelmajeed F.
Al-Jawabreh, Amer O.
Zaid, Taher M.
Letnik, Ilya
Abdeen, Ziad A.
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor & Francis
Abstract
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 as Bacillus thuringiensis based 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 OD600 0.2. 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.