以發酵法生產具官能基之聚酯材料

Abstract

本研究為利用微生物發酵生產生物可分解材料，實驗中除探討微生物之最適化環境外，另嘗試以不同結構之特殊碳源饋料，鑑定生合成產物之結構及物性，期望能獲得含特殊官能基之聚羥基烷酯。研究中採用之菌株為Pseudomonas oleovorans，當以6 g/L辛酸鈉(sodium octanoate)作為碳源，4 g/L硫酸銨為氮源進行發酵培養時，20小時所得菌體量為3.38 g/L，PHA累積量為0.71 g/L，PHA佔菌體乾重的26 %；當氮源添加0.66 g/L硫酸銨時，結果顯示對於此菌體為限氮環境，因此造成PHA大量累積，發酵20小時之產量可提升到 1.4 g/L，PHA content為46%；如改變氮源為yeast extract時，菌體生長及PHA累積的狀況都較佳，添加6 g/L辛酸鈉及16 g/L yeast extract，菌量可提高至5.84 g/L，饋入8 g/L辛酸鈉及2 g/L yeast extract時，PHA累積量達到1.63 g/L。 P. oleovorans饋以不同碳源發酵培養時，所生產之PHA結構也隨之改變，以辛酸鈉及壬酸為碳源時，分別可獲得PHO(poly(3-hydroxyoctanoate)及PHHN (Poly(3-hydroxyheptanoate-co-3-hydroxynonanoate))為主之共聚合物；當添加十一烯酸(undecylenic acid)為碳源時，可生合成由3-hydroxy-10-undecenoate，3-hydroxy-7-noneneoate，3-hydroxy-6-hepteneoate三種重複單元所組成的不飽和共聚物；如以苯戊酸(5-phenylvaleric acid)饋加，此聚酯高分子側鏈末端將為含有苯環結構之(Poly(3-hydroxy- 5-phenylvalerate))PHPV。藉由引入各種不同官能基之功能性可分解材料，將可增加應用的範圍。

Biosynthesis of biodegradable polymers using Pseudomonas oleovorans was conducted. Manipulations of carbon source as well as ingredients of fermentation medium were investigated. PHA (ployhydroxyalkanoate) incorporated with functional groups was anticipated. 3.38 g/L of dry cell weight and 26% of PHA content were obtained using P. oleovorans when dosing 6 g/L of sodium octanoate and 4 g/L of ammonium sulfate. 1.4 g/L of PHA were attained under a limitation of nitrogen source. PHA content was 46 % dry cell weight. If nitrogen source of medium were changed from ammonium sulfate to yeast extract, both cell concentration and weight of PHA were enhanced respectively. Fermentation with dosages of 6 g/L sodium octanoate and 16 g/L yeast extract were resulted in a high cell concentration (5.84 g/L). When dosing 8 g/L of sodium octanoate and 2 g/L of yeast extract, high PHA concentration was obtained (1.63 g/L). Different products of PHA were obtained by dosage of different carbon sources. Both PHO (poly(3-hydroxyoctanoate)) and PHHN (poly(3-hydroxyheptanoate-co-3-hydroxynonanoate))were the major co- polymers obtained by dosaging sodium octanoate and nonanoic acid respectively as a sole carbon source. PHA contained 3-hydroxy- 10-undecenoate，3-hydroxy-7-noneneoate and 3-hydroxy-6-hepteneoate units were obtained when feeding undecylenic acid as a sole carbon source. When dosing 5-phenylvaleric acid, PHPV(Poly(3-hydroxy-5- phenylvalerate)) with phenyl group were be synthesized. Introducing the various functional groups into the structure of PHAs facilitates the development of synthesizing new functionality biopolymers for many uses.