Abstract
This study aims to compare and analyze the chemical structures of bacterial biosurfactants produced by an indigenous Bacillus subtillis strain cultured in minimal salt medium (MSM) enriched with fresh cooking oil and used cooking oils that are cheaper and easy to obtained in huge quantities. Optimization of biosurfactants was successfully conducted in two MSMs enriched with 2% (v/v) fresh cooking oil and 2% (v/v) waste cooking oil respectively. The initial pH of growth medium was fixed at pH 7.64 and the whole fermentation process was maintained in a constant temperature of 30 °C. Chemical structures analysis of biosurfactants produced at 1L scale in bioreactor were conducted using spectroscopic methods such as Nuclear Magnetic Resonance (NMR) and Fourier-Transform Infrared spectroscopy (FTIR). The chemical compound isolated from the biosurfactant produced from the waste cooking oil was pentyl 2-ureidobut-3-enoate (1) while (1-hydroxyethyl)amino)methyl heptanoate (2) was isolated from the biosurfactant produced from fresh cooking oil. This study demonstrated the ability of Bacillus subtilis to produce a low-cost biosurfactant characterized as lipopeptide.