STK is a bacterial consortium with hydrophobic in nature render them to bind to polycyclic aromatic hydrocarbons via their hydrophobicities. This consortium is able to utilize pyrene as carbon and energy sources, however pyrene degradation by the consortium in soil was limited. The aim of the present study is to focus on pyrene degradation in soil on solid state in comparison with that of slurry state in both free cell system and immobilized cell system. The latter, cells were immobilized onto mixed leaves. After 28 days of incubation, the immobilized system showed a 4.08 % of pyrene remained in solid soil while 0.24% and 6.83% remained in aqueous phases of the slurry system after 10 days. In the case of free cell, less degradation was observed in solid soil as the result showed that amount of pyrene remained after 28 days of incubation was 66.89% comparing to control of 76%. While in the slurry system, the amounts of pyrene remained were 18.21% and 15.04 % in solid and aqueous phases, respectively, after 10 days of incubation. In term of long term storage, the immobilized STK was grown on plant waste materials for 14 days, moisture content was adjusted to 30% followed by packed under vacuum and store at the room temperature for 9 months. Periodically samples were taken and determined for pyrene degradation activities and bacterial viabilities at 0, 3, 6 and 9 months. Under the above circumstances, number of viable cells and amount of pyrene remained were found to be 9.23 log CFU/g and 2.08%, 7.59 log CFU/g, 49.96%, 7.57 log CFU/g, 51.80% and 7.15 log CFU/g, 58.49% in 3, 6 and 9 months, respectively.
