OPTIMASI PRODUKSI N-ACYLHOMOSERINE LACTONASE OLEH ESCHERICHIA COLI BL21(DE3) PADA SISTEM FED-BATCH SECARA INTERMITTENT FEEDING DENGAN VARIASI KONSENTRASI GLISEROL

• Main Author: Claretta, Bianca
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83337
• Institution: Institut Teknologi Bandung

Acute hepatopancreatic necrosis disease (AHPND) is a disease that affects the digestive system in white shrimp(Litopenaeus vannamei) and causes global losses in shrimp production of USD 43 billion. AHPND is caused by Vibrio parahaemolyticus bacteria that can produce toxins when quorum sensing events occur. Quorum sensing regulated by the autoinducer acyl homoserine lactone (AHL) can be inhibited by the enzyme acyl homoserine lactonase (AHL-lactonase) through the process of quorum quenching. Previous research has successfully excreted acyl homoserine lactonase enzyme encoded aiiA gene by Escherichia coli BL21 (DE3) inserted plasmid pET- 26b(+)-N20-aiiA-6xHis. Batch system fermentation using the two-stage temperature control strategy method with a temperature transfer of 27-37 C used in the previous study, successfully excreted more protein in the extracellular fraction, thus facilitating the downstream process. In this study, fed-batch fermentation and incubation temperature of 27-37oC were carried out with varying concentrations of glycerol in the feeding (300 g/L, 400 g/L, and 600 g/L) in an effort to increase cell production and the amount of enzyme produced. The purpose of this study was to determine the optimal glycerol concentration in the feeding media on cell growth, protein yield, and the presence of the target protein, N-acyl homoserine lactone. In this study, variations in glycerol concentration had no significant effect on cell growth and a positive impact on cell concentration. HPLC analysis showed that glycerol was not a limiting factor in the cultivation process. The final cell concentration in all three variations was in the same range of 109 CFU/mL. On the other hand, the 600 g/L glycerol concentration variation produced the highest protein yield of 11.57 mg/mL and the highest target protein yield was at the 600 g/L glycerol concentration variation. This study concludes that the addition of glycerol 600 g/L to the feeding media can be a strategy to increase protein productivity by E. coli BL21 (DE3)