Generation of putative biosurfactant producing mutant by β-Lactam Mutagenesis

Biosurfactant is valuable microbial product excreted extracellularly by microorganism. This microbial product has a clear advantage over commercial synthetic surfactants. Risen concern on bad effects of synthetic surfactants towards environments has led to the introduction of biological resources as an alternative. However, higher cost production and lower output become another challenge face by the industry. This project was conducted to generate mutant on bacteria strain with altered biosurfactant production. Gram-positive rod of isolate UMK A2 was induced by β-lactam mutagenesis in ampicillin treatment. 5 µg/mL ampicillin was determined as minimum inhibition concentration (MIC) towards isolate UMK A2 through well assay. Then, half of the MIC was used to induce mutagenesis in isolate UMK A2. In preliminary test, 161 colonies were patched on 5% of horse blood agar and shows β-hemo lys is activity. 10 colonies were chosen to proceed with biosurfactant screening assay. The screening including hemolysis test, drop collapse test, oil spreading test and emulsification test. These tests applied for qualitative and quantitative method to detect the present of altered biosurfactant production by mutant stains. From the tests conducted, M2 strain has 2 mm difference diameters in hemolysis zone, positive in drop collapse of palm oil, 3.80 cm in 1st batch and 3.77 cm in 2nd batch average diameter of oil displacement and forms 0.47 cm emulsion layer for both batches in engine oil than wild types. While, M4 strain has 1 mm difference diameter in hemolysis zone, 3.47 cm in 1st batch and 3.23 cm in 2nd batch average diameter of oil displacement and forms 1.07 cm in 1st batch and 0.50 cm in 2nd batch of emulsion layer in engine oil. From the observed result, it can be concluded that genes involved in biosurfactant production might be mutated during ampicillin treatment.