Kashyap Rahul, Palai Tapas, Bhattacharya Prashant K
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
Department of Chemical Engineering and Technology, Birla Institute of Technology Mesra, Ranchi, 835215, India.
Bioprocess Biosyst Eng. 2015 Dec;38(12):2417-26. doi: 10.1007/s00449-015-1478-4. Epub 2015 Oct 5.
Experimental investigations were made to synthesize fructo-oligosaccharides (FOS) from sucrose using fructosyltransferase. The influence of various parameters such as temperature (45-55 °C), pH (4-5), initial sucrose concentration (ISC: 300-500 g/L) and enzyme concentration (4-32 U/mL) were varied. A maximum FOS yield of 60% was observed at ISC 500 g/L, pH 4.5 with enzyme activity 32 U/mL and at 55 °C. It was confirmed that 1-kestose (tri-) was the major product of FOS as compared to nystose (tetra-) and fructosylnystose (penta-saccharides). Further, the reaction rate increases with increase in temperature. From separate sets of experiments, it was observed that FOS formation was affected by glucose inhibition. Apart from the increase in the rate of FOS formation with increasing enzyme activity, the final values of FOS yield increase though till 16 U/mL and thereafter attain plateau. A kinetic model was also developed, based on Michaelis-Menten kinetics, and a five-step ten-parameter model, including glucose inhibition, was obtained. Model was solved using COPASI(®) (version 4.8) solver for kinetic parameter estimations followed by time course simulations.
开展了实验研究，以利用果糖基转移酶从蔗糖合成低聚果糖（FOS）。对各种参数的影响进行了研究，如温度（45 - 55°C）、pH值（4 - 5）、初始蔗糖浓度（ISC：300 - 500 g/L）和酶浓度（4 - 32 U/mL）。在ISC为500 g/L、pH值为4.5、酶活性为32 U/mL且温度为55°C的条件下，观察到FOS的最大产率为60%。证实了与蔗果四糖（四糖）和果糖基蔗果四糖（五糖）相比，1-蔗果三糖（三糖）是FOS的主要产物。此外，反应速率随温度升高而增加。从单独的实验中观察到，FOS的形成受到葡萄糖抑制的影响。除了随着酶活性增加FOS形成速率提高外，FOS产率的最终值在酶活性达到16 U/mL之前增加，此后达到平稳状态。还基于米氏动力学建立了一个动力学模型，并得到了一个包括葡萄糖抑制的五步十参数模型。使用COPASI(®)（版本4.8）求解器对模型进行求解，以估计动力学参数，随后进行时间进程模拟。
