Thermochemical Lab, Chemical Engineering Department, Central Leather Research Institute (CSIR-CLRI), Adyar, Chennai, Tamilnadu, 600020, India.
Bioprocess Biosyst Eng. 2019 Jun;42(6):1009-1021. doi: 10.1007/s00449-019-02101-0. Epub 2019 Mar 11.
Air flow rate and agitation speed for inulinase production by Kluyveromyces marxianus were optimized based on metabolic heat release profiles. Shear stress and oxygen transfer (ka) values were compared to assess the effects of aeration and agitation. At agitation rates of ≤ 100 rpm, the oxygen mass transfer rates were small and eventually led to less inulinase production, but at agitation rates > 150 rpm, loss of biomass resulted in less inulinase activity. Bio-reaction calorimeter (BioRc1e) experiment with aeration rates ≤ 0.5 lpm showed low ka while at 1.5 lpm frothing of reactor contents caused loss of biomass and inulinase activity. The optimum conditions for aeration and agitation rate for K. marxianus in BioRc1e were 1 lpm and 150 rpm. Heat yield values obtained for the substrate, product and biomass reinstated the ongoing metabolic process. The heat release pattern could be a promising tool for optimization of bioprocess and in situ monitoring, with a possibility of interventions during the biotransformation process. At optimized aeration and agitation conditions, a two-fold increase in inulinase activity could be noticed.
基于代谢热释放曲线，优化了马克斯克鲁维酵母生产菊粉酶的空气流速和搅拌速度。比较了剪切应力和氧传递（ka）值，以评估通气和搅拌的影响。在搅拌速度≤100rpm 时，氧气传质速率较小，最终导致菊粉酶产量较低，但在搅拌速度>150rpm 时，生物量损失导致菊粉酶活性降低。通气速率≤0.5lpm 的生物反应量热计（BioRc1e）实验显示 ka 值较低，而在 1.5lpm 时，反应器内容物的泡沫会导致生物量和菊粉酶活性损失。BioRc1e 中 K.marxianus 的最佳通气和搅拌速度条件为 1lpm 和 150rpm。获得的底物、产物和生物量的产热量值证实了正在进行的代谢过程。热释放模式可能是优化生物过程和原位监测的有前途的工具，并有可能在生物转化过程中进行干预。在优化的通气和搅拌条件下，菊粉酶活性可提高两倍。
