柴油生物脱硫菌的筛选及应用研究

【作者】 张倩倩；

【导师】 马洁；

【作者基本信息】 首都师范大学 ， 物理化学， 2006， 硕士

【摘要】 以二苯并噻吩（DBT）作为模型化合物，从炼油厂污水中分离出一株专一性脱硫的红串红球菌TJQ，该菌能降解DBT，终产物为2-羟基联苯（2-HBP）。系统研究了初始pH值、碳源、氮源、硫源，脱硫代谢产物硫酸根(SO₄^2-)和2-HBP等因素对TJQ菌生长及脱硫的影响。并设计了小型生物脱硫反应器，考察了菌体在反应器中对不同体系中硫的脱除。为生物脱硫的工业化发展提供参考。 1．TJQ菌的最佳适宜的初始pH值为6.0～7.0，控制溶液pH在适宜值时可提高菌体的生长和脱硫能力；在不断监测和调节溶液pH值的反应体系中，菌株在3天内可将6.4mg／L（0.2mmol／L）水相中的DBT硫完全脱除，并可使2-HBP的浓度由22.98mg／L（0.135mmol／L）提高到31.66mg／L（0.186mmol／L），产率增加35％左右。 2．TJQ菌体生长所适合的碳源和氮源分别是20g／L的葡萄糖和1g/L的氯化铵；TJQ菌可以利用多种硫源作为生长硫源，其中硫酸钠（Na₂SO₄）和二甲基亚砜作为生长硫源能更有效地提高细胞收率，因此可以用廉价的无机硫源Na₂SO₄代替昂贵的有机硫源来培养菌体。 3．以Na₂SO₄作为硫源培养的TJQ菌体，可专一性脱除苯并噻吩（BT）和DBT及其甲基衍生物4，6-DMDBT中的硫，除此之外它还可以脱除苯硫醚（PS）类含硫化合物中的硫。在正十六烷模拟体系中，TJQ可以使噻吩（TH）硫由100mg／L降到3.6mg／L，脱硫率达到96.4％，使BT硫由207.1mg／L降到135mg/L，脱硫率达到34.8％；使DBT硫由150mg／L降到20mg／L，脱硫率达到86.7％，使4，6-DMDBT中的硫由100mg／L降到1.6mg／L，脱硫率达到98.4％，使PS硫由100mg／L降到52mg／L，脱硫率达到48％。把TJQ菌应用于加氢柴油体系中，循环脱硫三次可以使实际柴油中的总硫量由554mg／L降至267mg／L；脱硫率达到51.8％。 4．SO₄^2-和2-HBP作为菌体的脱硫代谢产物对菌体的生长脱硫有一定的影响。SO₄^2-的存在可以作为菌体的生长硫源促进菌体的生长，但会延长菌体的脱硫时间：以硫酸盐作为生长硫源培养的菌体用于脱硫实验，效果较好；并且当加入硫酸盐还原菌或者PYS菌去除SO₄^2-后，菌体能够将水相中12.8mg/L（0.4mmol／L）的DBT完全脱除，同时能使2-HBP的生成量由1.34mg／L（0.0079mmol／L）增加到33.74mg／L（0.1982mmol／L），提高了菌体的脱硫效率。 5．设计了新型生物脱硫反应器，经过小试连续反应2天，TJO菌能够在高浓度的DBT培养基中生长良好，可以将水相中DBT硫含量从19.2mg／L（0.6mmol/L）降至0.224mg／L（0.007mmol／L），脱硫率达到98.8％。菌体在反应仅1天后能使含硫量为463mg／L的正十六烷模拟体系中的硫降低到396mg／L，降解率为14.5％。在反应仅1天后能使含硫量为440mg／L的加氢柴油中的硫降低到386mg／L，降解率为12.3％。更多还原

【Abstract】 A new strain able to convert dibenzothiophene （DBT） into 2-hydroxybyphenyl （HBP）was isolated from the refinery sullage and was identified as Rhodococcus erythropolis TJQ. The effects of the initial pH,carbon source,nitrogen source,various sulfur compounds and desulfurization metabolic product SO₄^2- and 2-HBP on the growth and desulfurization activity of the strain TJQ was studied. A pint-sized desulfurization bioreactor was designed and the desulfurization activity of the strain in the reactor for different systems of sulfur was studied which was considered as a reference for the industrialized development of the biodesulfurization.1. The optimal initial pH for the growth of the strain varies from 6.0 to 7.0. The activity of TJQ’s growth and desulfurization can be improved when regulate the pH value in 6.0⁷.0. The TJQ was able to enhance the produce ratio of 2-HBP from 22.98mg/L（0.135mmol/L） to 31.66mg/L（0.186mmol/L） in aqueous media with 6.4mg/L（0.2mmol/L） DBT as the initial sulfur source during three days ,in this case the produce ratio of 2-HBP increased by 35% .2. The best carbon source and nitrogen source are glucose and ammonium chloride,respectively by 20g/L and 1g/L . The strain TJQ can use multiform sulfur as sulfur source while the sodium sulfate（Na₂SO₄） and the dimethylsulfoxide（DMSO） were the best,so replacing the high-priced organic sulfur source with the low-cost inorganic sulfur source（e.g. Na₂SO₄） was a feasible way to cultivate the strain.3. The TJQ cultivated with the sodium sulfate can effectively desulfurize benzothiophene （BT）, DBT and its derivatives 4,6-dimethyldibenzothiophene （4,6-DMDBT）.Besides,it can desulfurize the phenyl sulfide （PS）. The TJQ cells can remarkably desulfurize the thiophene （TH） sulfur from 100mg/L to 3.6 mg/L , the BT sulfur from 207.1mg/L tol35 mg/L , the DBT sulfur from 150mg/L to 20mg/L, the 4,6-DMDBT sulfur from 100mg/L to 1.6mg/L ,the PS sulfur from 100mg/L to 52mg/L, the desulfurization ratio respectively is 96.4%,34.8%,86.7%,98.4%,48% in the model oil （n-hexadecane containing different organic sulfur compound as the sole sulfur source）. When a hydrodesulfurized diesel oil with various organic sulfur compounds were treated with the TJQ resting cells and circled three times ,the total sulfur content significantly decreased from 554mg/L to 267mg/L for diesel oil,the desulfurization ratio is 51.8% .4. The effects of the desulfurization metabolic product SO₄^2- and 2-HBP on the activity of the TJQ growth and desulfurization were studied .The existing of the SO₄^2- can offer the vegetal sulfur source to TJQ ,but it will delay the desulfurization time limit; The resting cells cultivated with Sodium sulfate can effectively desulfurize various organic sulfur compounds. The produce ratio of 2-HBP was enhanced from 1.34mg/L（0.0079mmol/L） to 33.74mg/L（0.1982mmol/L） in aqueous media with 12.8mg/L（0.4mmol/L） DBT as the initial sulfur source when sulfate reducing bacteria or the strain PYS was added to remove the SO₄^2- to enhance the desulfurization ratio of the TJQ. The produce ratio of 2-HBP can be enhanced and the desulfurization ratio of the DBT was 100%.5. A new desulfurization bioreactor of the fuel oils was designed.The TJQ can grow well with high concentration of DBT In the bioreactor, it can desulfurize the DBT sulfur significantly from 19.2mg/L（0.6mmol/L） to 0.224mg/L（0.007mmol/L） ,and the desulfurization ratio is 98.8% in aqueous media during two days .It can desulfurize the DBT sulfur in the model oil （n-hexadecane containing DBT as the sole sulfur source） from 463 mg/L to 396mg/L and the desulfurization ratio is 14.5% during one day. It was able to remove 12.3% of the sulfur in the更多还原