【導(dǎo)讀】SunhoonKwon,Ik-KeunYoo,WooGiLee,HoNamChang,YongKeunChang. productivity,gL?1h?productivityof57gL?1h?1h?1

　　

【正文】 和幀過濾單元， 一個 Pellicon 2 BIOMAX 100V的（ 100 k NMWC ， ，超純水，貝德福德，馬）與隔膜泵， 和一個 P 07090 40 （科爾 Parmer ）的細(xì)胞再生裝置，其 CA流速為 600毫升/分鐘。 MCRB在接種前需要用含 50 ％ （ V / V ）乙醇的無菌水徹底清洗。在操作過程中，需不斷向發(fā)酵罐中加入新的培養(yǎng)基同時排出產(chǎn)物。為了防止細(xì)胞密度去超過一定限度，造成過濾功能下降，需要從發(fā)酵罐中不斷抽出少量的發(fā)酵液 。在這兩個階段發(fā)酵過程中，從第一階段流出的發(fā)酵液用于第二階段中。 數(shù)值分析方法 發(fā)酵動力學(xué)的參數(shù)可以用最小二乘回歸來估算。利用 Matlab （ MathWorks 公司，公司，美國） 軟件進行數(shù)值積分找到穩(wěn)態(tài)值和約束多變量優(yōu)化以尋找到最佳操作變量。限制利用的優(yōu)化是最大的細(xì)胞密度（ Xm）和最大其余血糖濃度（ s） 。 討 論 為了提高生物反應(yīng)器產(chǎn)乳酸的性能，我們對連續(xù)乳酸發(fā)酵系統(tǒng)加上膜細(xì)胞分離技術(shù)（ MCRB ）進行了研究。大大增加在固定體積發(fā)酵罐中的細(xì)胞密度，生產(chǎn)率比傳統(tǒng)的間歇和連續(xù)發(fā)酵提高了 10 倍以上。然而，乳酸實際生產(chǎn)中，最主要因素經(jīng)濟上的可行性 ，此方法乳酸濃度高于 95 g / L時，細(xì)胞的生長幾乎完全受到抑制。在初步單 MCRB實驗中 ，即使在細(xì)胞密度保持在高于 90 g / L時，得到的乳酸濃度仍然很低，約 51政 / L，（圖 4 ）。當(dāng)加入一個體積比 MCRB大 9的 CSTR時，在放出細(xì)胞液之前如果讓它在在 MCRB反應(yīng)器中停留更長的時間， 則乳酸濃度會明顯提升，會達到 87 g / L圖 6 ） 。由此我們可以得出這樣的結(jié)論：在第二個反應(yīng)器 CSTR與另一 MCRB 相連并且兩個階段的生物反應(yīng)器與細(xì)胞循環(huán)同在這兩個階段前提下，可以高速生產(chǎn)高濃度的乳酸，如果使用兩 個MCRBs 系列，則可以以 57 g L?1 h?1 的生產(chǎn)速率生產(chǎn)出濃度達到 92 g / L的乳酸（圖 12 ） 。 最后，通過優(yōu)化多步驟 MCRBs 反應(yīng)器，可以得到預(yù)期想得到的最優(yōu)生產(chǎn)乳酸的方法，實驗證明，利用兩階段 MCRBs 反應(yīng)器可以高速生產(chǎn)高濃度的乳酸，從而使固定容積反應(yīng)器的生產(chǎn)效率大大提高（ A型） 。 參考文獻 [1] Aeschlimann A, Stasi LD, von Stockar U. 1990. 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