探討嗜鹽菌於不同導電度和以大豆水解液作為氮源醱酵生產Polyhydroxyalkanoate之研究

Effect of Conductivity on the Production of PHA by H. mediterranei Using Soybean Hydrolyte as Nitrogen Source

張希文(Hsi-Wen Chang)

指導教授 ： 陳志成

大同大學/工程學院/生物工程學系所/碩士(2004年)

摘要

本研究以嗜鹽菌Haloferax mediterranei採用重覆式批次饋料醱酵，利用廉價的擠壓米糠、澱粉與大豆水解液來生產polyhydroxyalkanoate (PHA)之研究。利用導電度來測量醱酵液中鹽濃度的變化及決定饋鹽的時機。發現導電度維持在3.0 S/m的饋料醱酵中，在82 hr可得最佳之菌體量為117 g/L，而PHA含率可達54.1% g/g菌體重。實驗發現在維持導電度於3.0 S/m時，加大醱酵液中的澱粉濃度，有助於菌體量之生長。PHA之收率(yield)可達0.30 g PHA/g 碳源。以廉價的大豆水解液取代酵母萃取物，在醱酵118 hr後，菌體量可以穩定維持在59.1 ~ 62.1 g/L，其PHA含率可達64.8%，而PHA 收率達0.38 g PHA/g 碳源，本研究有助於降低PHA的生產成本，而提升其在分解性塑膠市場上的競爭力。

關鍵字

導電度 ； 大豆水解液

並列摘要

Haloferax mediterranei was cultivated by repeated fed-batch fermentation to produce polyhydroxyalkanoate (PHA) by using cheap extruded rice bran/starch and soybean hydrolyte. Conductivity detector was used to estimate the salt concentration of broth, and also to determine the suitable salt feeding for conductivity control. It was found that maintaining conductivity at 3.0 S/m resulted the maximum cell concentration of 117 g/L; the PHA content can reach 54.1 % g/g cell. Under the conductivity around 3.0 S/m, enhancing the concentration of starch in the broth would promote the cell growth. The PHA yield reach 0.30 g PHA/g carbon source. Using cheap soybean hydrolyte to replace yeast extract resulted stable cell concentration at 60 g/L after 118 hrs of culture; we could harvest cells with PHA content of 64.8 %, and PHA yield can reach 0.38 (g PHA/g carbon source). This study help to reduce the production cost of PHA and enhance the competitiveness of PHA in the market of biodegradable plastics.

並列關鍵字

conductivity ； soybean hydrolyte

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