De-emulsification by Rhodococcus erythropolis NTU-1

This report investigated the feasibility of applying Rhodococcus erythropolis NTU-1 that possessed de-emulsifying ability to recover oil from oil-in-water (O/W) emulsion.
Suspended NTU-1 cell reach de-emulsification efficiency up to 90% and recovered 85% oil in 24 hr. Besides, the optimal amount of NTU-1 cell addition was 3 mL (OD600=1) when Oil/Water/Tween80 was 2~8/1/0.01.
Heat-dried bioflocculi also were tested because of its convenience in practical application. Dried bioflocculi retained its high hydrophobicity, resulting in more than 85% de-emulsification and 85% oil recovery in 12hr. When Oil/Water/Tween80 volume is 2~9/1/0.01, the optimal amount of dried NTU-1 was 0.03 g. It was estimated and calculated that 250 mL oil might be recovered by 1 g dried bioflocculi.
Lower Tween80 concentration or O/W ratio and higher temperature, better de-emulsification and oil recovery in less time. In addition, the optimal amount of NTU-1 for de-emulsification, for both suspended and dried NTU-1, was proportional to the amount of Tween80 to the power of 2/3, indicating a surface area dependent behavior.
These experimental results showed that NTU-1 in MSM or dried bioflocculi had a potential role in enhancing tertiary oil recovery process.