利用本土菌株Pseudomonas aeruginosa J16醱酵生產鼠李醣脂之探討

Rhamnolipid production with an indigenous isolate Pseudomonas aeruginosa J16

鄭捷倫(Chieh-Lun Cheng)

指導教授 ： 魏毓宏

元智大學/工程學院/生物科技暨生物資訊研究所/碩士(2007年)

摘要

本研究使用自石化廢水篩選所獲得之台灣本土菌株Pseudomonas aeruginosa J16進行其代謝產物鼠李醣脂之定性、定量及醱酵生產策略上的討論。研究證實P. aeruginosa J16具代謝合成生物界面活性劑鼠李醣脂之能力，經高效液相層析儀、核磁共振光譜儀、快速原子撞擊質譜儀分析証實P. aeruginosa J16合成之鼠李醣脂主要為單鼠李醣脂及雙鼠李醣脂。其次經研究証實，P. aeruginosa J16最適合生產鼠李醣脂的碳、氮源分別為甘油及硫酸銨，其最佳產量為2.8 g/L。上述培養基進一步利用回應曲面實驗設計法求得最佳化培養基組成為Glycerol 3.5 %、(NH4)2SO4 33.25 mM、NaHPO4 40 mM、KH2PO4 40 mM、CaCl2 6 μM、 MgSO4．7H2O 577 μM、EDTA 4 μM、FeSO4．7H2O 4 μM。研究証實P. aeruginosa J16利用回應曲面實驗設計所得之最適化培養基，能將鼠李醣脂產量提升至4.2 g/L，為基礎培養基的7倍，最高產率為0.044 g/L/h。
於重複批次實驗研究上，可讓鼠李醣脂產率達0.086 g/L/h，為批次實驗之1.8倍，且可以連續操作三個批次以上，每批次產量皆可達4.3 g/L以上，並且將醱酵時間縮短兩倍。在饋料批次策略上，以菌體濃度作為添加營養源時機，成功的得到鼠李醣脂最佳產量8.8 g/L為批次實驗的1.9倍，為基礎培養基之17倍，在產率上也有明顯提升可達0.073 g/L/h，此結果顯示，以菌體濃度作為添加營養源時機，為一方便且具效率之醱酵方式。

關鍵字

鼠李醣脂

並列摘要

Abstract
Pseudomonas aeruginosa J16 isolated from wastewater of a petrochemical factory located in southern Taiwan was used in the present work for qualitative、quantitative and production of rhamnolipid. Recent researchers reported that rhamnolipid is a biosurfactant primarily produced by Pseudomonas aeruginosa. The results of HPLC、 13C NMR and mass spectrometry analysis show that the biosurfactant consisted mainly of mono-rhamnolipid (RL1) and di-rhamnolipid (RL2). Preliminary tests indicated that a combination of glycerol and (NH4)2SO4 as the carbon and nitrogen source gave a good rhamnolipid production of 2.8 g/L. The optimal formulation was identified by response surface methodology (RSM) as follows: glycerol (3.51%), (NH4)2SO4 (33.3 mM), NaHPO4 (40 mM), KH2PO4 (40 mM), CaCl2 (6 μM), MgSO4.7H2O (577 μM), EDTA (4 μM), and FeSO4.7H2 (4 μM). Statistical experimental design methodology was not only applied to optimize the culture medium composition but further enhanced rhamnolipid production of 4.2 g/L and productivity of 0.044 g/L/h. The repeat-fed batch strategy not only abridges the time of fermentation about two times but also could repeat this process and get the same results at least three times. In each batch, this strategy could enhance rhamnolipid concentration and productivity were 4.3 g/L and 0.086 g/L/h, respectively. In fed batch strategy, fed timing is controlled by the change of optical density, and the best rhamnolipid production which successfully got was 8.8 g/L, approximately 1.9-fold higher than batch experiment and 17-fold higher than original medium. The results show that the fed batch strategy was convenient and efficient method for rhamnolipid production.

並列關鍵字

Rhamnolipid

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