重组人血清白蛋白在汉逊酵母中的高密度发酵表达

Recombinant human serum albumin expression in genetically engineered Hansenula polymorpha high - density fermentation

考察了不同甲醇流加策略对重组汉逊酵母(Hansenula polymorpha)高密度发酵表达重组人血清白蛋白的影响.溶氧控制法不能有效地防止甲醇的过量流加,气相色谱离线检测法虽然控制了甲醇流加过量,但甲醇浓度的波动较大,利用甲醇传感器在线检测控制甲醇的流加可维持较恒定的甲醇浓度.在重组汉逊酵母表达人血清白蛋白的诱导阶段,采用甘油-甲醇混合补料的培养方式,限制性速率流加甘油以增加表达期间的能量供应,以溶氧水平作为甘油代谢指针来控制甘油限制性流加既维持菌体生长,又不会因发酵液中残余甘油及有害代谢产物阻遏蛋白表达.经甲醇甘油混合流加优化后,表达阶段细胞平均比生长速率控制于0.012 h^(-1)时,细胞干重达到150g/L,重组人血清白蛋白表达量达3.5g/L.

Four different methanol feeding modes were evaluated in the human serum albumin production in high - density fermentation by Hansenula polymorpha. It was difficult to avoid methanol excessive in the broth with the feeding strategy only based on DO level. On the othe hand , the fluctuation in methanol concentration was observed with methanol feeding strategy by off- line gas chromatography. However, the stable methanol concentration was perfectly achieved by the on - line monitoring with methanol sensor. The supply of energy was improved by feeding glycerol at a limited rate as well as methanol in the induction phase. Therefore, the high cell dry weight of broth reaches 150 g/L and the maximum rHSA concentration was 3.5 g/L at the 120th hour at the fed- batch fermentation of recombinant Hansenula polymorpha by methanol- glycerol mixed feeding.