Oil Recovery of Soil Contained Petroleum Oil by Using Bio surfactant of Mixed Cultures Bacteria (Brevundumonas diminuta, Pseudomonas fluorescens, Pseudomonas aeroginosa, Pseudomonas citronelis) at vary pH Conditions (5-9)

Abstract The bacteria (Brevundumonas diminuta, Pseudomonas fluorescens, Pseudomonas aeroginosa, Pseudomonas citronelbis) which are indigenous bacteria from Babat Toman village South Sumatra. It were isolated and identified by using Bergey's method. In the normal condition (pH 7), these bacteria could produce bio surfactant and effectively as mixed culture. The growth of mixed culture of indigenous bacteria was tested at different pH conditions (5-9). The results show that  the optimum pH was obtained at pH 7, the population of bacteria was  2.14.107 cfu/mL. The shortest regeneration time of these bacteria were (12, 12, 9, 9) hours respectively. The initial total petroleum hydrocarbon concentration of sample was 18,4 %, it was extracted by using the bio surfactant of mixed culture with 10 % concentration at different pH conditions (5-9), the contact time as long as 168 hours. The optimal oil recovery was obtained at pH 7 as much as 20.97 %. It can be concluded that the bio surfactant effectively used in the normal condition (pH 7) and ineffectively in alkaline condition (pH 9).The GC analyses were conducted to initial crude oil and the residue. The results show that the crude oil consists of 33 components, and the residue consists of 14 components. It shows that the bio surfactant of mixed culture bacteria dissolved the hydrocarbon components with temperature fractions 150, 155, 178, 184, 190, and 197 o C.