柴油脱硫菌的筛选及发酵条件研究

Study on the Selection and Fermentative Condition of Bacterium about Diesel Desulfuration

首先以二甲基亚砜为唯一硫源,通过初筛,筛选出28株菌株,再以二苯并噻吩(DBT)为唯一硫源复筛,筛选出降解DBT较好的菌株HT1。菌株液体发酵实验表明,菌株HT1生长的最适pH值为6.5～7.5,最佳温度30℃;酸性和碱性条件均对菌株的生长有抑制作用,二苯并噻吩降解能力降低;以葡萄糖作为碳源菌株生长最好,但存在底物抑制作用,以甘油作为碳源时,菌株生长及DBT降解能力略低,但不存在底物抑制作用;菌株HT1既能利用有机氮源也能利用无机氮源,但利用有机氮源的能力远远大于无机氮源,对DBT的降解能力却正好相反,其中以硝酸铵作为氮源时,对DBT降解能力最大。最终确定甘油为最佳碳源,浓度为5 g/L,硝酸铵为生长氮源,最佳浓度为2 g/L。

First, 28 strains were selected by using dimethyl sulfoxide as the sole sulfur source, then HT1 strain was selected which has high desulfurization ability by using dibenzonthiophene dibenzothiophene （DBT） as the sole source of sulfur. Strain liquid fermentation of the HT1 reveals that the optimum pH and temperature for its growth is 6.5--7.5 and 30 ℃, respectively. The HT1 strain could be inhibited under acid or alkaline condition and the ability of DBT degradation decreases. The growth of the strain prospered with glucose as carbon source, but the substrate could inhibit its growth. The HT1 strain growth and its DBT degradation ability were slightly lower with glycerol as carbon source and the substrate cannot inhibit its growth. The HT1 strain can better utilize organic nitrogen sources than inorganic ones; however, it has the best DBT degradation effect with ammonium nitrate as nitrogen source. Therefore, we come to the conclusion that the best carbon source is 5 g/L glycerol and the best nitrogen source is 2 g/L ammonium nitrate.