利用Rhodococcus erythropolis NTU-1細胞破乳化

Abstract

本研究目的主要探討R. erythropolis NTU-1之破乳化的特性，其能利用此菌株使油水乳化液在短時間內能分離出油。 以菌液破乳化的研究結果發現，乳化劑Tween80可以將正十六烷與水互相混合形成白色乳化液，利用NTU-1菌液可以在24小時內可以回收85%以上的正十六烷，破乳化效率也高達90%。同時發現在O/W/T為2~8/1/0.01，並不影響最適添加NTU-1菌液量(3 mL,OD600=1)。 若以烘乾經正十六烷培養的NTU-1結塊細胞破乳化，該細胞粉末雖然不具活性，但仍保有很高的疏水性，亦可以使破乳化效果在12小時內就達85%以上且回收85%以上的正十六烷。同時，在O/W/T為2~9/1/0.01，並不影響乾燥NTU-1結塊的最適添加量(0.03 g)。經實驗可估算出1 g的乾燥結塊約可以回收250 mL 的正十六烷。 實驗發現在低乳化劑濃度0.2%或油/水(O/W)比值越小或高破乳化溫度下，可以提高破乳化程度及縮短破乳化時間。另外，藉由改變不同乳化劑體積，發現最適添加NTU-1細胞(不論是菌液或是乾燥結塊)與Tween80體積存在面積比(量的n=2/3次方)的關係。 由此可知，NTU-1菌液或是烘乾後的NTU-1結塊皆具有很好的破乳化能力，可以在24小時就回收80%以上的正十六烷，此項成果確實在三級原油回收方面，提供一個相當具有競爭性及發展性的方法。

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.