摘要
从孤岛油田油浸土壤中筛选得到能降解二苯并噻吩（DBT）的红平红球菌DS-3，对其进行了固定化研究．选取海藻酸钠（SA）-聚乙烯醇（PVA）为包埋固定化载体，以1mmol·L^-1二甲基亚砜培养菌体，固定化最佳操作条件为4℃交联，8％PVA和2％SA混合，细胞在胶液中的浓度为0．1g·ml^-1，氯化钙含量为2％，此时固定化细胞不但具有良好的脱硫性能，而且脱硫重复性好，其寿命可以达到250h以上．固定化细胞在3次循环后能使模拟柴油中的DBT含量从0．5mmol·L^-1降至0．011mmol·L^-1，总脱硫率达到93％，平均脱硫效率约为0．225mgDBT·（gDCW）^-1·h^-1．同样条件下能将精制柴油的硫含量由340mg·L^-1降到42mg·L^-1，总脱硫率为87．64％．DS-3能利用醇类、饱和的C8～C15脂肪烃，但不能利用环烷烃、芳香烃、小于C8或大于C15的脂肪烃，DS-3优先利用碳源的顺序是乙醇、葡萄糖和烷烃．脱硫前后的精制柴油经GC—FID分析证实，同定化细胞对C—S键具特异性，不降低柴油的热值．
Immobilization of the bacterium Rhodococcus erythropolis DS-3 cells, which was isolated from the oil-soaked soil of Gudao oilfield and could decompose dibenzothiophene （DBT） by 4S pathway, was studied. The effects of immobilization conditions on the bacterium＇s bio desulfurization characteristics and on desulfurization of diesel fuel were investigated. The results showed that the immobilized cells with sodium alginate and polyvinyl alcohol as the immobilized carrier and 1 mmol·L^-1 dimethyl sulfoxide as the culture medium showed good bio desulfurization characteristics and long natural life. The optimum immobilized condition was 4℃ crosslinking temperature with the concentrations of sodium alginate 2G, polyvinyl alcohol 8%, cells to mixed carrier ratio 0.1 g ·ml^-1 and calcium chloride content 2%. After three cycles of circulated desulfurization, the content of DBT decreased from 0.5 to 0. 011 mmol·L ^-1, the overall rate of desulfurization was 93%, and the average desulfurization efficiency was about 0. 225 mg DBT · （g DCW）^-1· h^-1. The refined diesel fuel with sulfur content 340 mg· L^-1 could be desulfurized by immobilized cells to alowsulfur contentof42 mg·L^-1. Furthermore, the reuse and life periods of immobilized cells were much better than unimmobilized cells. The life periods of the reactivated immobilized cells reached more than 250 h· DS^-3 could utilize alcohol, saturated aliphatic alkane which has a C8--C15 carbon chain as its sole carbon source, but could not utilize cycloalkane, aromatic hydrocarbon and saturated aliphatic alkane which has a carbon chain shorter than hexane or longer than hexadecane. The preference of carbon source was in the order of ethanol, glucose and alkane. GC-FID analysis of refined diesel fuel before and after bio-desulfurization showed that the composition of alkane had little change during bio-desulfurization. It was indicated that the desulfurization of DS-3 specifically cut carbon sulfur bond but had no effect on alkane.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2006年第11期2705-2713,共9页
CIESC Journal
基金
天津市自然科学基金项目(05YFJMJC00700)
中国博士后科学基金项目(2005038460).~~
关键词
海藻酸钠
聚乙烯醇
固定化细胞
红平红球菌
生物脱硫
sodium alginate
polyvinyl alcohol
immobilized cells
Rhodococcus erythropolis
bio-desulfurization
