Abstract: Mycobacterium sp. ZD-19 can metabolize dibenzothiophene(DBT) and 4,6dimethyldibenzothiophene(4,6DMDBT) through a sulfur-specific pathway. The biodesulfurization of 4methyldibezothiophene(4MDBT) by ZD-19 was also investigated in this thesis. The results showed that ZD-19 can also desulfurize 4MDBT through a sulfur-specific pathway. The metabolic pathway for biodesulfurization of 4MDBT was studied, and the final product of 4MDBT biodesulfurization was determined by GC-MS, which were identified as two isomers: 4-methyl-2phenylphenol and 2-hydroxy-3-methyl-biphenyl.
Biodesulfurization of DBT in oil-aqueous system was carried out in the ALR. The optimal gas velocity was 11.8cm/s. Slight plug-flow was formed when the gas velocity achieved 13.0cm/s, and the oil droplet diameter and the interface area decreased consequently, which were the main causes of the decreased desulfurization rate. The biodesulfurization of resting cells of ZD-19 could be proceed in the non-growth media (phosphate buffer) as efficiently as in the growth medium (BSM). The desulfurization rate increased with the increasing of DBT concentration as well, while high DBT concentration would inhibit the activity with an optimal of 3 mmol·L-1. The results suggested that under high concentration of DBT and optimal gas velocity, the mass transfer rate was much higher compared to DBT conversion rates, when the microbial desulfurization rate was the overall rate-limiting process step.
Keywords：biodesulfurization; airlift reactor; simulated fuel oil; Mycobacterium sp.; dibenzothiophene(DBT) ; alkylated dibenzothiophenes(Cx-DBTs)
II
目 录
中文摘要 I
英文摘要 II
目录 III
1. 绪论 1
1.1 燃料油中的硫及其危害 1
1.2 燃料油脱硫技术 2
1.2.1 催化加氢脱硫 3
1.2.2 生物脱硫 3
1.3 生化反应设计 4
1.3.1 搅拌式反应器 4
1.3.2 气升式反应器 5
1.4 生物脱硫存在的问题 6
1.5 本论文的研究内容 7
2. 实验部分 8
2.1 实验材料 8
2.1.1 仪器与试剂 8
2.1.2 培养基 8
2.1.3 实验用生物菌种制备 9
2.1.4 菌种衰退防止和保藏 9
2.1.5 气式反应器实验装置 10
2.2 实验方法 11
2.2.1 细胞浓度测定 11
2.2.2 有机杂环化合物及其产物测定 11
2.3 微生物脱硫性能研究 13
2.3.1 摇瓶中休止细胞脱硫活力测定 13
2.3.2 反应器中休止细胞脱硫活力测定 13
