ANALYSIS OF MICROBIAL COMMUNITY IN OIL FIELD USING CULTURE-INDEPENDENT AND CULTURE-DEPENDENT FOR MICROBIAL ENHANCED OIL RECOVERY (MEOR)

• Main Author: Hilda Efendi, Silfana
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57884
• Institution: Institut Teknologi Bandung

Oil production in Indonesia has a deficit so that it has not been able to fulfill market demand. Meanwhile, the oil demand continues to increase. One of the efforts developed is Microbial Enhanced Oil Recovery (MEOR) which aims to increase the productivity of oil recovery by utilizing microorganisms through the metabolites they produce. Identification and exploration of bacteria in oil reservoirs are one of the important information in MEOR. In this study, exploration of the microbial community was carried out in the ABG-02 Jatibarang well and the LDK-21 Cepu well. This study aims to analyze the microbial community in both wells that have the potential for MEOR using culture-independent and culture-dependent method. Culture-independent was carried out by sequencing the 16S rRNA gene from environmental samples using next-generation sequencing (NGS). The sequencing results were analyzed using tools, namely QIIME2 for taxonomy annotation and PICRUSt2 for prediction annotation. The culture-dependent approach was carried out by isolating microbes on agar plates and screening at 50 oC. Then isolate is performed macroscopic and microscopic morphological characterization. The isolates obtained were identified by MALDI-TOF MS. Based on the taxonomic analysis, 9 predominant bacterial phyla in LDK-21 well were obtained from Proteobacteria, Bacteriodetes, Firmicutes, Chloroflexi, Actinobacteria, Patescibacteria, Caldatribacteria, Desulfobacteria, and Thermatoga groups, with the highest relative abundance in the Bacteriodetes phylum. Meanwhile, in ABG-02 well, only 6 phyla were identified, namely Proteobacteria, Bacterioidetes, Firmicutes, Chloroflexi, Actinobacteria, and 1 unidentified group, with the highest relative abundance being the Proteobacteria group. The value of microbial alpha diversity in the wells was calculated using the Shannon, Simpson and Chao1 indices, indicating the value of the LDK-21 well was higher than that of the ABG-02 well. The diversity of microbial abundance in the LDK-21 well belongs to the category of moderate diversity and moderate community stability and has a higher estimated number of species compared to ABG-02 well. Based on the function prediction analysis using the KEGG database, it is predicted that in both wells there will be bacteria that have metabolic pathways K00626 and K01897, which are pathways for biosynthesis and degradation of fatty acids. Microbes in both wells were also predicted to have enzymes EC.2.3.1.9, EC.6.2.1.3, and EC.6.4.1.2 which play a role in the production of Acyl-CoA for the biosynthesis of lipids such as rhamnolipids. Based on the analysis with the MetaCyc database, it is also predicted that the microbes in both wells have a beta-oxidation metabolic pathway which is the core pathway in lipid biosynthesis. Meanwhile, culture-dependently, 15 thermophilic isolates were isolated from ABG-02 well and 10 thermophilic isolates were obtained from LDK-21 well. The isolates that were isolated in both wells were dominated by groups of Gram-positive bacteria and were in the form of bacilli. The isolates in well ABG-02 that were identified were Bacillus licheniformis, Bacillus cereus, Bacillus subtilis, and Bacillus pumilus. Based on this research, it can be concluded that both culture-dependent and culture-independent can be used to predict indigenous microbes from wells. In addition, in the both wells some microbes have the potential for physiological functions to be applied to MEOR technology.