海洋石油降解菌Alcanivorax sp. 97CO-5的固定化及其石油降解效果

Immobilization of a marine oil degrading bacterium Alcanivorax sp. 97CO-5 and its oil biodegradation properties

本文应用不同材料固定海洋石油烃降解菌Alcanivorax sp.97CO-5,考察并比较了其成型、传质、包埋菌体活性和石油降解性能。实验结果表明：2.5%海藻酸钠包埋材料中细菌的增长最为显著,8 d后材料中细菌数量达到1.2×106CFU/g,为初始细菌细胞数量的3.85倍,是最适的固定化材料。固定化菌剂的石油降解实验结果表明,固定化菌剂14 d对石油的净降解率达到34.1%,其石油降解效果优于游离菌体（28.3%）;气相色谱质谱联用分析表明,固定化菌剂对石油中总烷烃降解率为57.9%,其中对nC21～nC31的中长链烷烃的降解率可达到54.6%;固定化菌剂相对于游离菌体,对芴（FLU）和二苯并噻吩（DBT）两类烷基化多环芳烃的降解率明显提高,达到44.9%和44.2%,而游离降解菌仅为25.4%和24.7%。实验证明,固定化技术促进了Alcanivorax sp.97CO-5菌体降解性能的发挥尤其是对中长链烷烃和部分芳烃成分的降解。

In this research,a marine oil degrading bacterium Alcanivorax sp. 97CO-5 was immobilized in different materials. The formability and mass transfer property of these materials,as well as survival rate and oil degrading capacity of the embedded cell were investigated and compared. The results showed that 2. 5% sodium alginate enabled the fastest bacterial growth. Cell density in the material reached 1. 2 × 10^6CFU /g after 8 days,which was 3. 85 times of the initial density. 2. 5% sodium alginate was the optimum immobilization material to embed the bacterium. The results of oil degrading capacity show that the degradation rate of immobilized bacteria reached 34. 1% in 14 days. It was higher than that of bacteria in liquid culture（28. 3%）. The degradation rate of total alkanes reached 57. 9% by GC-MS analysis and long chain alkanes from nC21 to nC31 reached 54. 6%. The degradation rates of the immobilized bacteria against polycyclic aromatic hydrocarbons（PAHs） were significantly higher compared to liquid culture,with a degradation rate of 44. 9% for fluorene（FLU） and 44. 2% for dibenzothiophene（DBT）. The degradation rate of bacteria in liquid culture is only 25. 4% for FLU and 24. 7% for DBT. The results indicated that immobilization of Alcanivorax sp. 97CO-5 can enhance its oil degradation ability especially for long chain alkanes and aromatic hydrocarbons.