Characterization and Enhanced Degradation Potentials of Biosurfactant-Producing Bacteria Isolated from a Marine Environment

Abstract

At present, improvement in the degradation effect of diesel-degrading bacteria by combining them with surfactant-producing bacteria is an important way to efficiently repair the ecology of oil-contaminated areas. Among the 14 bacterial isolates, three diesel-degrading bacteria showed better degradation performance, with degradation rates of diesel of 50.52% (HDMP1), 42.70% (HDMP2), and 36.46% (HDMP3). Three biosurfactant-producing bacteria showed better emulsifying ability. The (E24) values of the biosurfactant against diesel were determined to be 55% (HDMB1), 81% (HDMB2), and 73% (HDMB3). The best surfactant-producing bacteria (HDMB2) produce lipopeptide biosurfactants that can be observed by the presence of peptide and carboxyl groups using Fourier transform infrared spectroscopy. In addition, the interaction between the diesel-degrading bacteria and biosurfactant-producing bacteria was evaluated and we found that the combination of HDMP1 and HDMB2 had significant performance for oil removal (the degradation rate of diesel was 67.38%), which indicated its future application in a microbial enhanced oil recovery process.