ISOLATION OF BIOSURFACTANT PRODUCING BACTERIA IN NATTO WHICH HAS POTENTIAL AS ANTIMICROBIAL COMPOUNDS

• Main Author: TANARIS , MELANIA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/53904
• Institution: Institut Teknologi Bandung

Biosurfactants are amphiphilic compounds that could have antimicrobial activity property. Therefore biosurfactants could be used in the food industry to extend the shelf life of a product. Microorganisms with the ability to produce biosurfactants are generally microorganisms found in soil or pathogenic microorganisms. To avoid health problems due to the consumption of biosurfactants, non-pathogenic microorganisms are needed. This study aims to isolate bacteria in Natto, a Japanese fermented food, which has the ability to produce biosurfactants. These biosurfactants were tested for their potential as antimicrobials against four types of bacteria (Aeromonas hydrophila, Staphylococcus aureus, Erwinia cypripedii, and Bacillus stearothermophilus) and four types of fungi (Rhizopus stolonifer, Aspergillus niger, Saccharomyces cereviseae, and Candida albicans). Natto was isolated on Nutrient Agar (NA) medium. Screening of bacterial isolates was carried out based on three methods, namely blood agar hemolysis, oil dropping test, and emulsification index (E24). Isolates with the best screening results are used for biosurfactant production using Mineral Salt Medium (MSM) and the yield obtained is measured. Biosurfactants were tested for antimicrobial activity using the broth microdilution and Kirby-Bauer methods. Biosurfactants were analyzed using a Fourier Transform Infra Red (FTIR) spectrophotometer to see the characteristics of their constituents. Twelve bacterial isolates were obtained from NA medium. All isolates showed beta hemolysis in blood agar. Isolate 7B showed the best screening results with a clear zone diameter of 105 mm as oil dropping test results and 56.7% as E24. Isolate 7B has a yield of 0.2518 g / L. MIC biosurfactant isolate 7B was observed at a concentration of 100 mg / mL for the four tested bacteria. No clear zone was found in the Kirby-Bauer test results for the four test fungi. Biosurfactant isolate 7B belongs to the lipoprotein group with the FTIR spectrum that most closely resembles surfactin. This study showed that the 7B bacterial isolate from natto had the highest yield to produce biosurfactants. The lipoprotein biosurfactant has potential as antibacterial and has no potential as antifungal.