Isolation of Biosurfactant Producing Bacteria from Oil Reservoir, Characterization of Biosurfactant Product and Optimization Inorganic Nitrogen Nutrition

• Main Author: Fadhliani
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/34275
• Institution: Institut Teknologi Bandung

The usage of microbes for oil recovery is one of EOR methodes which doesn?t require large investment. Microbes in this case hydrocarbonoclastic bacteria in the reservoir be able to produce bio-surfactants, alcohols, bio-polymers, gases, and acid through metabolic processes. In this research isolation bacteria from reservoir that potential to produce biosurfactant and optimization inorganik nitrogen to increased biosurfactant production. Isolation was done by using 2 phases using brine medium and 0,1% yeast extract at a temperature of 50 ° C and agitation 120 rpm. The first phase of the isolation was conducted using 5% crude oil ( non steril) and 5% brine (non steril), the second phase was conducted using residual oil degradation. . Bacteria obtained from this process was further adapted in gradual temperature from 50 °C, 60 °C, and 70 °C using SMSSe medium. The next step was screening of biosurfactant production bacteria by using hemolytict test, emulsification, and interfacial tension. The best surfactant producing bacteria was adapted in SMSSe medium with gradual oil concentration (10%,15% and 20%). Making the growth curve, biosurfactant production curve, and "critical micelle concentration" curve is performed by using SMSSe medium. The next step was inorganic nitrogen optimization of its source and its concentration using ammonium sulfate, NPK, and ammonium nitrate to increased biosurfactant production. The best nitrogen source varied by 0,1%; 0,15% and 0,2%. Biosurfactant stability tested in range temperature ((32 °C, 40 °C, 50 °C, 70 °C dan 121 °C), salinity (5%, 10%, 15% dan 20% ) and pH (2,4,6,8, dan 10). Identification of bacteria was conducted using 16S rRNA. Analysis biosurfactant produced using FTIR. Twelve bacteria were obtained from the isolation process, eight isolates from the first phase and four isolates from the second phase. Four isolates which have the highest emulsification index is 1,7,9, and 11 with value is 87,5%; 70,58% 72,72% and 70,96%. Isolate 1 showed the best result for all test, decreased interfacial tension was 60,71% compared with isolates 7,9,11 with decreased interfacial tension about 54,28%; 54,28%; and 52,85%. The growth curve showed that isolates 1 has the highest growth rate was 0,2018 h-1 at the 60 hours. The highest biosurfactant production was 2,361 g/L which was reach at 96 hours with rate of biosurfactant formation 0,0048 g/hour. The Critical Micelle Concentration (CMC) point was 1,813 g/L. Ammonium nitrate was the best inorganic nitrogen source that produced the highest biosurfactant 2,262 g/L and the biosurfactant rate iv 0,02172 g L-1h-1 which was reach at 120 hours, compared with NPK and ammonium sulfate which only produces thehighest biosurfactant 0,688 g/L and 0,735 g/L with rate of productiont 0,0099 g L-1 h-1 and 0,0189 g L-1 h-1 at 120 hours. Ammonium nitrate concentration was 0,1%; 0,15% and 0,2% produced biosurfactant 2,262 g/L; 2,105 g/L; and 2,367 g/L and decreased interfacial tension 22,15%; 22,50% and 24,29%. Identification 16S rRNA showed the nearest relationship with Bacillus subtilis. FTIR spectrum of extracted biosurfactant tentatively characterized the biosurfactant as lipopeptide. The Biosurfactant activity was stable at high temperature (32 °C, 40 °C, 50 °C, 70 °C dan 121 °C), salinity (5%, 10%, 15% dan 20% ) and pH (2,4,6,8, dan 10) also optimuum at 70 °C, salinity 20% dan pH 8.