Fed-batch cultivation of Saccharomyces cerevisiae on lignocellulosic hydrolyzate
Fed-batch cultivation of Saccharomyces cerevisiae on lignocellulosic hydrolyzate
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DOI：
10.1007/s10529-006-9227-z
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发表时间：
2007-01
影响因子：
2.7
通讯作者：
Anneli Petersson;G. Lidén
中科院分区：
文献类型：
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作者：
Anneli Petersson;G. Lidén
在木质纤维素稀酸水解液厌氧发酵生产燃料乙醇过程中，酵母菌生长很差。然而，在水解产物上有氧生长的酵母细胞对水解产物的耐受性增加。因此，在部分水解产物上培养酵母具有在水解产物的发酵中能够提高乙醇生产率的潜力。为了评估酵母在水解产物中生长的能力，使用乙醇浓度作为输入变量来控制进料速率，进行分批补料培养。然后，通过在培养期间将乙醇浓度控制在低水平，酵母以0.19 h-1的比生长速率在未脱水的水解产物中生长。然而，与合成培养基相比，在水解产物上培养的生物质产率较低：在乙醇设定点为0.25 g/l的情况下，在水解产物上的产率为0.46 g/g，而合成培养基为0.52 g/g。差异的主要原因不是乙醇产量本身，而是在高比生长速率下甘油的显著产量。甘油的产生可能归因于呼吸能力不足。
Saccharomyces cerevisiaegrows very poorly in dilute acid lignocellulosic hydrolyzate during the anaerobic fermentation for fuel ethanol production. However, yeast cells grown aerobically on the hydrolyzate have increased tolerance for the hydrolyzate. Cultivation of yeast on part of the hydrolyzate has therefore the potential of enabling increased ethanol productivity in the fermentation of the hydrolyzate. To evaluate the ability of the yeast to grow in the hydrolyzate, fed-batch cultivations were run using the ethanol concentration as input variable to control the feed-rate. The yeast then grew in an undetoxified hydrolyzate with a specific growth rate of 0.19 h−1by controlling the ethanol concentration at a low level during the cultivation. However, the biomass yield was lower for the cultivation on hydrolyzate compared to synthetic media: with an ethanol set-point of 0.25 g/l the yield was 0.46 g/g on the hydrolyzate, compared to 0.52 g/g for synthetic media. The main reason for the difference was not the ethanol productionper se, but a significant production of glycerol at a high specific growth rate. The glycerol production may be attributed to an insufficient respiratory capacity.