Publications by authors named "Shuangming Tong"

During enzyme immobilization, enzyme activity and protein distribution are affected by various factors such as enzyme load, temperature, and pH. In general, two types of protein distribution patterns (heterogeneous or homogeneous) are observed inside a porous carrier, owing to differences in preparation parameters. During the immobilization of a fusion protein (CCApH) of cephalosporin C acylase (CCA) and pHluorin (a pH-sensitive mutant of green fluorescent protein), different shaking speeds induced obvious differences in protein distribution on an epoxy carrier, LX-1000EPC.

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Article Synopsis
  • In a stirred tank reactor, the pH dropped from 8.5 to 7.2 during catalysis with immobilized cephalosporin C acylase (CCA), affecting enzyme stability due to diffusional resistance.
  • Adding phosphate and bicarbonate buffers improved conditions, allowing CCA to successfully catalyze 15 batch reactions without a significant pH gradient.
  • Using 0.2 M ammonium bicarbonate buffer in a packed bed reactor resulted in continuous catalysis for 21 days with high conversion rates (≥95%), enhancing enzyme stability and efficiency compared to nonbuffered systems.
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