Demulsification capabilities of a Microbacterium species for breaking water-in-crude oil emulsions

African Journal of Biotechnology, Vol. 12(16), pp. 2019-2026, 17 April, 2013, DOI: 10.5897/AJB11.3462
Demulsification capabilities of a Microbacterium species for breaking water-in-crude oil emulsions
Hossein Salehizadeh 1,2*, Aida Ranjbar 2 and Kevin Kennedy 1
1 Department of Civil Engineering, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
2 Chemical Engineering Group, Faculty of Engineering, University of Isfahan, Isfahan, Iran.
Abstract
A bacterium strain belonging to Microbacterium sp., isolated from oily sludge samples of Siri Island in the south of Iran, produced a strong, thermo stable microbial demulsifier (Yx/s=0.663, Yp/s=0.204, productivity=0.185 g L-1 h-1) on glucose as a sole carbon source supplemented with yeast extract. The optimum values of temperature, inoculum concentration, pH and culture age for microbial demulsifier production were 25°C, 108 CFU mL-1, 7 and 24 h, respectively. The maximum demulsification activity and the half-life value (t1/2) of culture broth measured for a water-in-crude oil (W/CO) emulsion were 96.4% and 36 h at 80°C in flask. The demulsifier was purified to homogeneity using cold ethanol. For 4.33 mg mL-1 of partially purified microbial demulsifier, the half-life value for the W/CO model emulsion was 3 h.
This work aimed to investigate the behavior of a demulsifier isolated from Microbacterium sp. on water and crude oil (W/CO) model emulsions, optimization of growth conditions and factors influencing microbial demulsifier production as well as the effect of the W/CO demulsification, assay temperature and inoculum concentration on the model emulsion. 
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