脱硫菌R-8的生长及其生物降解水中二苯并噻酚

Growth of Pseudomonas delafieldii R-8 and Biodegradation of Dibenzothiophene in Aqueous Solution

以二苯并噻酚(DBT)为唯一硫源考察了pH、温度、碳源、氮源等对德氏假单胞菌(Pseudomonas delafieldii)R(8生长的影响. 结果表明,该菌的最适生长pH范围为6-9,最适生长温度为30oC,甘油是细胞生长的最好碳源,最佳浓度范围为10-15 g/L,最佳无机氮源乙酸铵的浓度为 1.6 g/L. 有机氮源能促进细胞的生长,但对从DBT脱硫却产生抑制作用. 硫酸钠、二甲基亚砜、胱氨酸和蛋氨酸等硫化物都可以作为R-8生长的硫源,但对R-8脱硫活性的表达没有诱导作用.

Pseudomonas delafieldii R-8 isolated from coal contaminated soils in our laboratory could metabolize DBT to 2-hydroxybiphenyl via the sulfur-specific pathway. Effects of initial pH, sources of carbon and nitrogen of the culture media were investigated by using DBT as the sole source of sulfur in aqueous phase. It was indicated that this strain grew well in the pH range of 6~9 and the optimal temperature for growth was 30oC. Glycerol was the optimal carbon source and the optimal concentration was 10 g/L. Organic nitrogen sources including yeast extract, bacto-typtone and beef typtone were conducive to the growth of this strain, but repressed the expression of the desulfurization activity of R-8 even in the presence of DBT. Ammonia acetate was the appropriate source of nitrogen at the concentration of 1.6 g/L. Although sodium sulfate, dimethyl sulfoxide, methionine, cysteine and DBT could be used as the sole sources of sulfur respectively, these sulfur-containing compounds except DBT could not induce the expression of the biodegradation activity of R-8.