Analysis of biological demulsification process of water-in-oil emulsion by Alcaligenes sp. S-XJ-1.
A demulsifying strain (S-XJ-1) was isolated from petroleum-polluted soil and identified as Alcaligenes sp. It showed emulsion breaking ratio of 81.3% for W/O emulsion within 24h when the cell concentration was 500mg/L. Evolution of water droplets during the biological demulsification process was investigated using a Turbiscan stability analyzer and microphotography. Further investigation focused on cell surface hydrophobicity and oil-water interfacial properties. The biological demulsification process began with rapid dispersal of the cells into the oil phase and adsorption onto the oil-water interface. This occurred due to high cell surface hydrophobicity and the presence of amphiphilic compounds in the cell walls. The cells had higher interfacial activity than the emulsifier molecules, and they displaced some of the emulsifier molecules, which effectively reduced the interfacial tension gradient. As a result, the interfacial film strength decreased, the water droplets coalesced and eventually phase separation occurred.
Wen
Yue
Y
College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 20092, China.
Cheng
Hang
H
Lu
Li-Jun
LJ
Liu
Jia
J
Feng
Yi
Y
Guan
Wei
W
Zhou
Qi
Q
Huang
Xiang-Feng
XF
D000421:Alcaligenes / Q000166:cytology / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D001709:Biotechnology / Q000379:methods*; D002462:Cell Membrane / Q000378:metabolism; D004655:Emulsions; D057927:Hydrophobic and Hydrophilic Interactions; D009821:Oils / Q000737:chemistry*; D013500:Surface Tension; D014867:Water / Q000737:chemistry*
D004655:Emulsions; D009821:Oils; D014867:Water