GROWTH OF Bacillus Megaterium CSK2, Bacillus Subtilis CSK3 AND Bacillus Subtilis CSK4 ISOLATED FROM COAL MIXED SOIL IN DIBENZOTHIOPHENE-CONTAINING MEDIUM

摘要

Biodesulfurization is an environmentally friendly technology to reduce organic sulfur in coal by utilizing bacterial metabolism. Isolation and identification of bacteria from coal-mixed soil from South Sumatra has been conducted in order to obtain bacteria which desulfurize organic sulfur in local coal. Three viable isolates, i.e. CSK2, CSK3, and CSK4, were obtained by using a mineral medium containing glucose as carbon source and dibenzothiophene as sole sulfur source. Molecular identification of 16SrRNA gene sequences showed that the isolates had 99% similarity to genus Bacillus, which CSK2 was related to B. megaterium, while the isolates CSK3 and CSK4 were related to B. subtilis. Growth examination of the isolates within 48 hours in the dibenzothiophene-containing medium showed specific growth rate of 0.313, 0.270, and 0.194 h1, whereas the use of dibenzothiophene in the period of incubation was 37.4,16.7, and 25.9 percent of the initial 0.1 mM dibenzothiophene, by B. megaterium CSK2, B. subtilis CSK3, and B. subtilis CSK4 respectively. The results showed that the isolates derived from coal-mixed soil have potential to be developed in desulfurization of organic sulfur in coal.