利用生質柴油副產物生產聚羥基烷酸酯及其物性分析

本研究利用六株格蘭氏陰性細菌Duganella zoogloeoides TF1-1、Pseudomonas mosselii TO7、Pseudomonas nitroreducens PO6、Pseudomonas citronellolis PO21、Duganella zoogloeoides TS18及Paracoccus versutus GG45培養在含生質柴油副產物的礦物鹽培養基中48小時，觀察聚羥基烷酸酯的累積情形。其中以TF1-1及TO7兩株菌的PHA含量最高，分別為55 mol %及48 mol %。利用氣相層析分析聚合物單體組成，TF1-1所生成的PHA具有3-HB單體(100 mol%)，TO7生合成的PHA單體組成以3-HO (83 mol %)及3-HB(15 mol %)為主。以1H 及13C NMR解析聚合物結構，證實TF1-1所生合成的聚合物為PHB，TO7生合成的PHA，具有P(3HB)及P(3HO)的組成，與氣相層析分析結果一致。另外以傅立葉轉換紅外線光譜儀鑑定此兩株菌生產的PHA之官能基，證實具有PHA的C=O官能基訊號、C-O-C伸張模式的訊號，CH、CH2及CH3皆有吸收鋒出現。凝膠滲透層析儀測定TF1-1及TO7的PHA之廣分佈係數分別是1.30及1.38。熱性質分析結果顯示TO7及TF1-1的PHA產物裂解溫度分別為281.52oC及222.43oC；微差熱掃描分析結果顯示TF1-1的PHA產物比一般短鏈PHA的結晶度為低，具有較廣之應用性。為研究培養溫度及培養時間對於菌體內PHA分子量變化的影響，本研究以TO7為研究對象，以辛酸鈉為單一碳源觀察，結果顯示廣分佈係數無顯著的變化趨勢，但分子量分佈情形在高溫下培養有變高的趨勢，證實培養溫度對於分子量變化有影響。本研究結果顯示TF1-1及TO7兩株菌可以利用生質柴油副產物為碳源生成聚羥基烷酸酯，有較低的廣分佈係數，具備工業發展的潛力。

關鍵字

聚羥基烷酸酯

並列摘要

The six gram negative bacteria strains, Duganella zoogloeoides TF1-1, Pseudomonas mosselii TO7, Pseudomonas nitroreducens PO6, Pseudomonas citronellolisPO21, Duganella zoogloeoides TS18 and Paracoccus versutus GG45 were cultured in the MS medium containing biodiesel by-product to accumulate PHA. Among them, strains of TF1-1 and TO7 have the higher PHA content which were 55 mol % and 48 mol % , respectively. Gas chromatography revealed the monomer composition of polymer from TF1-1 utilizing BDF by-product was completely 3-HB (100 mol%), whereas the monomer unit of TO7 is primarily 3-HO (83 mol %) and 3-HB (15 mol %). NMR displayed the pattern of polymer produced by TF1-1 identical to the spectra of PHB. NMR spectrum of polymer produced by TO7 corroborates the composition and the expected structure analyzed by GC analysis. FTIR spectra show the absorption band CH , CH2 , CH3, ester bond and C-O-C band stretching. GPC analysis showed PDI values of the polymer produced by TF1-1 and TO7 were 1.3 and 1.38. The culture temperature and time have no predominant effects on the PDI value change. But molecular weight distribution curve gradually changed to a bimodal after 44 h at 35℃, suggesting the cultivation temperature is a factor involved in molecular weight change. This study showed the TF1-1 and TO7 will be potential candidates for industrial production of PHA with low PDI value and lower crystallinity from inexpensive waste substrate.