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標題: | 利用 Rhodococcus erythropolis NTU-1 細胞聚集現象移除正十六烷 Rhodococcus erythropolis NTU-1 Biofloccules for n-Hexadecane Removal |
作者: | Hui-Min Hsieh 謝惠敏 |
指導教授: | 劉懷勝(Hwai-Shen Liu) |
關鍵字: | 細胞聚集現象,正十六烷,冷凍乾燥,烘乾, Rhodococcus erythropolis NTU-1,biofloccules,freeze-drying,heat-drying,n-hexadecane removal, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 本研究目的主要在於探討如何提升及應用R. erythropolis NTU-1的細胞聚集現象,使長鏈烷類在短時間內能大量移除。
研究結果發現,在培養錐形瓶中加入篩網可幫助迴旋式培養下NTU-1與正十六烷的接觸機會及形式,因而NTU-1在44小時內即能形成結塊,配合物理撈除的方式可將2000 ppmv正十六烷移除掉95%以上。 利用冷凍乾燥的方式來保存以NB培養的NTU-1細胞,實驗結果發現使用麥芽糖溶液作為冷凍乾燥保護劑,並存放於-20℃的環境下,乾燥的NTU-1在經過30天存放後仍具有很高的存活率且其生理特性並不會受到影響。同樣利用冷凍乾燥的方式來乾燥以正十六烷培養而得的NTU-1細菌結塊,然而實驗結果顯示乾燥後的NTU-1結塊活性很低,無法再降解烷類,但其再形成結塊包覆烷類的能力並不會受到影響,1 ~ 2小時內即能再次形成聚集體,第12小時以物理撈除的方式可移除80 ~ 90%濃度為2000 ppmv的正十六烷。 接著以烘乾的方式取代成本高及費時的冷凍乾燥法來乾燥NTU-1結塊。實驗中選擇烘乾溫度為80℃,其乾燥所需時間約15小時且乾燥後的NTU-1結塊具有良好形成聚集包覆烷類的效果。這個部分換算出利用1g/L的NTU-1結塊密度來處理10000 ppmv的正十六烷較佳。另外,若以兩段式添加乾燥NTU-1結塊的方法,可使正十六烷的移除效率在12小時內由90%提升至將近100%。 乾燥後NTU-1結塊再形成聚集將烷類包覆的原因與其細胞表面疏水性及完整性有關,此兩項特性需同時存在,乾燥NTU-1結塊才能貼附烷類且以堆疊的方式形成大顆粒結塊。 由此可知,將NTU-1結塊冷凍乾燥或烘乾後保存,利用乾燥NTU-1結塊的高度包覆烷類能力,配合物理撈除的方式,使烷類能在12小時內大量移除,此項成果無疑的為將來石油污染物移除提供了一個相當具競爭性及發展性的方法。 Rhodococcus erythropolis NTU-1 is a strain which can not only degrade hydrocarbons but also traps alkanes in biofloccules during bioremediation process. In this study, we focused on how to accelerate biofloccules formation and to apply NTU-1 biofloccules for n-hexadecane (n-C16) removal. Results showed that sieves in Erlenmeyer flasks increased the n-C16 agitation efficiency under orbital shaking and assisted NTU-1 to utilize n-C16. NTU-1 formed biofloccules and trapped most residual n-C16 within 44 hr. At this time, more than 95% n-C16 was removed. NTU-1 cells (cultured by Nutrient Broth) by freeze-drying preserved most viability with maltose as the protectant. However, freeze-dried NTU-1 biofloccules (cultured by n-C16) resulted in low cell viability. Dried NTU-1 biofloccules did not degrade n-C16 but they still re-formed biofloccules and re-trapped most of n-C16. With these freeze-dried biofloccules, n-C16 removal efficiency achieved 80 ~ 90% within 12 hr. Heat-dried biofloccules were further evaluated because of its simplicity in comparison with freeze-drying method. It proved a good method and we found 1g/L dried cell vs. 10000 ppmv n-C16 was an optimal ratio. Moreover, with two-step addition of dried NTU-1 biofloccules, near 100% of n-C16 was removed in 12 hr. The mechanism of re-forming biofloccules was found to relate to the cell hydrophobicity and integrity. With these two characteristics, dried NTU-1 biofloccules adhered to n-C16, and n-C16 worked as the linker to form cell pellets in a short time. These dried biofloccules provided a feasible and potential method for remediation of hydrocarbon pollutants. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/10087 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 化學工程學系 |
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