Abstract:[Background] Efficient strains are the key to the biodegradation of oil pollutants. [Objective] To screen an efficient oil-degrading strain, optimize its immobilization conditions, and evaluate the oil degradation efficiency of the immobilized strain. [Methods] A highly efficient oil-degrading strain was isolated from traditional bacon in Pingxiang by the plate culture method and identified by 16S rRNA gene sequencing. The safety of the strain was evaluated based on three pathogenic indicators. The immobilization conditions of the strain were optimized by single factor tests and an orthogonal design. The degradation effects of the immobilized strain and free strain on soybean oil were compared. Furthermore, the reuse effect and the degradation effect of the immobilized strain on the oil in sewage were evaluated. [Results] The strain was identified as Staphylococcus sp., and it was not pathogenic. The optimal immobilization conditions for the strain were 4.0% sodium alginate, 2.0% CaCl2, sodium alginate solution:strain suspension volume ratio of 1:1, and crosslinking for 8 h. In the case of degrading soybean oil at pH 7.0, 30.0 ℃, and 180.0 r/min for 3 days, the immobilized strain achieved the highest degradation rate of 65.7%, which was 14.1% higher than that of the free strain. Moreover, the immobilized strain had tolerance to a wider pH range and stronger thermal stability than the free strain, and it demonstrated high oil-degrading ability after being repeatedly used for 4 times. [Conclusion] The degradation rate of the immobilized strain reached 41.6% for the oil in sewage. The immobilized strain can degrade both soybean oil and sewage oil, demonstrating a broad application prospect.
