Bioconversion of Palm Oil into Biosurfactant by <i>Halomonas meridiana</i> BK-AB4 for the Application of Corrosion Inhibitor

Abstract

Biosurfactant is environmentally friendly surfactant produced by a certain microorganism in a lipid-rich medium. A previous study has shown that Halomonas meridiana BK-AB4 had the potential of a moderately halophilic bacterium in converting olive oil into biosurfactant. In the present study, the effect of changing the carbon source from olive oil into cheaper and more abundant vegetable oil, which is palm oil, for the production of the biosurfactant was evaluated. The study began by optimizing the production medium with varying the nitrogen source, the concentration of palm oil and pH. The optimum condition of biosurfactant production was observed in the medium consisted of 0.6% (w/v) of urea, 2% (v/v) of palm oil and pH 9. The resulted biosurfactant was stable at pH 7-10 and in the salt concentration of 6-15%. Biosurfactant activity in lowering air-water surface tension was measured using the Du Noüy ring method, and the value of critical micelle concentration (CMC) was about 233 ppm. At this point, the surface tension of water dropped from 68.3 to 49.8 dyne/cm. Preliminary structural analysis by using FTIR technique suggested that the resulted biosurfactant has -OH, -C-H aliphatic C=C, H-C-C and C=O groups in its structure, which is similar to that of the fatty-acid type of biosurfactant. The potential of biosurfactant as a metal corrosion inhibitor was evaluated by using electrochemical impedance spectroscopy (EIS) that measured at 30 °C. The measurement revealed that the highest inhibition level was observed at the biosurfactant concentration about 200 ppm that corresponds to the inhibition level about 53.23%. ABSTRAKBiosurfaktan adalah surfaktan ramah lingkungan yang diproduksi oleh mikroorganisme tertentu dalam media kaya lemak. Dalam studi sebelumnya, telah ditemukan potensi bakteri halofilik, Halomonas meridiana BK-AB4, dalam mengkonversi minyak zaitun ke biosurfaktan. Dalam penelitian ini dipelajari efek variasi sumber karbon dari minyak zaitun ke minyak yang lebih murah dan berlimpah, yaitu minyak sawit, untuk produksi biosurfaktan. Studi ini dimulai dengan mengoptimalkan produksi media pada berbagai sumber nitrogen, konsentrasi minyak sawit dan pH. Kondisi optimum produksi biosurfaktan diamati dalam medium yang terdiri dari 0,6% (b/v) urea, 2% (v/v) minyak sawit dan pH 9. Produksi biosurfaktan stabil pada pH 7-10 dan konsentrasi garam 6-15%. Aktifitas biosurfaktan dalam menurunkan tegangan permukaan air-air diukur menggunakan metode cincin Du Noüy, nilai konsentrasi Misel kritis (CMC) adalah sekitar 233 ppm. Pada titik ini, tegangan permukaan air menurun dari 68,3 ke 49.8 dyne/cm. Analisis awal struktur menggunakan teknik FTIR dihasilkan bahwa biosurfaktan memiliki gugus -OH, -C-H alifatik C=C, H-C-C dan C=O dalam strukturnya, yang mirip dengan jenis asam lemak biosurfaktan. Potensi biosurfaktan sebagai inhibitor korosi logam dievaluasi menggunakan spektroskopi impedansi elektrokimia (EIS) yang diukur di 30 °C. Pengukuran menunjukkan bahwa tingkat inhibisi diamati pada konsentrasi biosurfaktan sekitar ...

Process Optimization of Palm Oil Mill Effluent-Based Biosurfactant of Halomonas meridiana BK-AB4 Originated from Bledug Kuwu Mud Volcano in Central Java for Microbial Enhanced Oil Recovery

“…According to the functional groups detected in the FTIR analysis, the crude biosurfactant extract produced belonged to the fatty acid class of biosurfactants. The results obtained were similar to those reported by Sari et al [3].…”

“…The detection of a carboxylic acid functional group indicates that the biosurfactant produced belongs to the fatty acid class of biosurfactants, whereas the presence of C-H bonds denotes the existence of long hydrocarbon chains composed of hydrophobic or non-polar groups typically found in biosurfactants [36]. A C=C bond points to the presence of a double bond, which may be influenced by unsaturated fatty acids used as carbon sources [3,37]. According to the functional groups detected in the FTIR analysis, the crude biosurfactant extract produced belonged to the fatty acid class of biosurfactants.…”

“…EOR technology generally utilizes surfactants, emulsifiers, polymers, and solvents, all of which pose a relatively high risk of environmental pollution [1]. In contrast, microbial enhanced oil recovery (MEOR) technology exploits microorganisms that produce biosurfactants [2,3]. These biosurfactants can be synthesized from inexpensive substrates, and they are non-toxic and can be degraded naturally, thereby making them an attractive alternative to EOR based on chemicals.…”

“…Previous research examined the ability of H. meridiana BK-AB4 to produce biosurfactants using olive oil and palm oil substrate [3]. However, as these two vegetable oils are food commodities with high demand, their use in biosurfactant production would give rise to competition with other sectors, especially the food sector.…”

“…However, as these two vegetable oils are food commodities with high demand, their use in biosurfactant production would give rise to competition with other sectors, especially the food sector. Biosurfactant synthesis by microorganisms occurs when they are cultivated in lipid-rich media [3].…”