The potential for establishment of axial temperature profiles during solid-state fermentation in rotating drum bioreactors.
The potential for establishment of axial temperature profiles during solid-state fermentation in rotating drum bioreactors.
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DOI：
10.1002/bit.10356
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发表时间：
2002-10
影响因子：
3.8
通讯作者：
D. Mitchell;A. Tongta;D. M. Stuart;N. Krieger
中科院分区：
文献类型：
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作者：
D. Mitchell;A. Tongta;D. M. Stuart;N. Krieger
用于固态发酵的转鼓式生物反应器（rdb）内的混合和传热现象研究较少。利用传热模型探讨了在基材床内建立轴向温度梯度的可能性。对于米曲霉在24 L RDB内的麦麸上生长，在空气表面速度为0.0023 m s（-1）和相对湿度为15%的条件下，该模型预测在快速生长期间进风口和出风口之间的轴向温度梯度为2摄氏度，而实验轴向温度梯度为1到4摄氏度。在这些操作条件下，整个床层都会出现不希望出现的高温。但该模型预测，对于204 L RDB，使用表面速度为1 m s（-1）的潮湿空气（相对湿度为90%）可以实现良好的温度控制。对于2200l RDB，预测良好的温度控制，表面速度低至0.4 m s(-1)，每当滚筒出口端的温度超过生长的最佳温度时，气流就从90%切换到15%。这项工作表明，在那些缺乏轴向混合的rdb中可能出现显著的轴向温度梯度。因此，建议在rdb内使用有角度的升力来促进轴向混合。
The mixing and heat transfer phenomena within rotating drum bioreactors (RDBs) used for solid-state fermentation processes are poorly studied. The potential for the establishment of axial temperature gradients within the substrate bed was explored using a heat transfer model. For growth of Aspergillus oryzae on wheat bran within a 24 L RDB with air at a superficial velocity of 0.0023 m s(-1) and 15% relative humidity, the model predicts an axial gradient between the air inlet and outlet of 2 degrees C during rapid growth, compared to experimental axial temperature gradients of between 1 and 4 degrees C. Undesirably high temperatures occur throughout the bed under these operating conditions, but the model predicts that good temperature control can be achieved using humid air (90% relative humidity) at superficial velocities of 1 m s(-1) for a 204 L RDB. For a 2200 L RDB, good temperature control is predicted with superficial velocities as low as 0.4 m s(-1) with the airflow being switched from 90% to 15% relative humidity whenever the temperature at the outlet end of the drum exceeds the optimal temperature for growth. This work suggests that significant axial temperature gradients can arise in those RDBs that lack provision for axial mixing. It is therefore advisable to use angled lifters within RDBs to promote axial mixing.