INFLUENCE OF CONSORTIUM CULTURE AND MIXED CULTURE ON CARBON STEEL CORROSION IN B30 STORAGE SYSTEM

• Main Author: Baihaqi, Byan
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/73716
• Institution: Institut Teknologi Bandung

<p align="justify"> Biodiesel is a renewable fuel that is being developed in Indonesia. Biodiesel development has reached B30, which is a mixture of 30% biodiesel and diesel oil. The use of B30 in Indonesia is regulated in the B30 Mandatory Program. Biodiesel is stored in storage tanks made of carbon steel. Biodiesel is hygroscopic and easily degraded, can trigger corrosion caused by microbes, which is called biocorrosion. In the B30 storage system, microbes utilize B30 as a carbon source and form biofilms which cause an increase in the corrosion rate of carbon steel. This research aims to compare the interaction effect of consortium culture and mixed culture on corrosion of carbon steel in B30 storage system. The consortium cultures used were Serratia marcescens-Bacillus megaterium and Serratia marcescens-Bacillus licheniformis. Meanwhile, the mixed culture used was biofilm isolates from metal soaked in B30. Results of this study show that colony growth of S. marcescens was lower than B. megaterium and B. licheniformis in consortium culture. Whereas the growth of bacterial and fungal colonies in mixed culture was not significantly different. The highest corrosion rate value of carbon steel was caused by the S. marcescens-B. Megaterium consortium culture. Biofilm morphology in the consortium culture was dominated by B. megaterium and B. licheniformis. Meanwhile, the morphology of mixed culture biofilms is a combinaion of the morphology of bacteria and fungi. The metal surface morphology on consortium culture and mixed culture produces pitting corrosion. Corrosion products produced by the consortium culture and mixed culture are Fe2O3, Fe3O4, and FeOOH. In the consortium culture, antagonistic interactions occurred, namely inhibition of S. marcescens growth activity due to the formation of thick biofilms and production of antimicrobials by B. megaterium and B. licheniformis as well as corrosion inhibitor is produced by B. licheniformis. Meanwhile, there was a synergistic interaction between the microbes in the mixed culture. The corrosion mechanism that occurs in consortium cultures and mixed cultures involves the same electrochemical reactions.