INFLUENCE OF CULTURE TYPE INTERACTION ON BIOFILM FORMATION, CARBON STEEL CORROSION, AND FUEL DEGRADATION IN B35 STORAGE SYSTEM

• Main Author: Baihaqi, Byan
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81431
• Institution: Institut Teknologi Bandung

Biodiesel is a biofuel which is renewable and more environmentally friendly. The use of biodiesel as fuel in Indonesia has reached B35 (a mixture of 35%-v biodiesel and 65%-v petrodiesel). The B35 storage system is designed from carbon steel material because it is cheap, easy to fabricate, and has good mechanical properties. However, biodiesel has the weakness of being more polar, easily degraded and more hygroscopic, causing material incompatibility between carbon steel and B35. In addition, B35 can be utilized by microbes for growth and metabolism. This condition causes biocorrosion and a decrease fuel quality. This study aims to compare the influence of culture type interaction on biofilm formation, carbon steel corrosion, and fuel degradation in the B35 storage system. The results of this research include that for each type of culture, the growth of Serratia marcescens biofilm colonies was significantly lower than the growth of Bacillus subtilis, Pseudomonas aeruginosa and Micrococcus luteus biofilm colonies. In addition, the mass loss of carbon steel tends to decrease with increasing immersion time. Meanwhile, the highest to lowest carbon steel corrosion rates were the SM-BS, SM-PA, and SM-ML consortium cultures, respectively. Biofilm morphology is dominated by one microbe at a certain immersion time. Meanwhile, the surface morphology of the metal forms pits and thick corrosion products. All types of cultures can degrade ester and hydrocarbon and can cause an increase in the acidity of B35 fuel beyond the specified specifications. In addition, biofilms of all types of cultures consist of carbohydrates, proteins, lipids, water, and peroxide. Meanwhile, the corrosion products of all types of culture are Fe2O3, Fe3O4, FeOOH, and Fe3(PO4)2. There were antagonistic interactions occur with Serratia marcescens through quorum sensing, the formation of thick biofilms, and the production of antagonistic compounds so that the corrosion rate decreases. Then, the corrosion mechanism involves with the relatively same electrochemical reactions. In the B35 storage system, the fuel quality decreases but carbon steel still has relatively good resistance.