Building on the previously mentioned context of enzyme applications in pharmaceutical synthesis, enzyme catalysts face various limitations in practical implementation. The core issues are as follows:
Significant stability issues
As enzymes are proteins, they are highly sensitive to external conditions such as temperature, pH, and ionic strength. They readily denature and lose activity in high-temperature or extreme pH environments. Consequently, conventional free enzymes have short shelf lives and operational lifespans, making it difficult for them to meet the rigorous operating conditions required for certain industrial reactions.
Application scope limited by specificity
The high substrate specificity of enzymes is a double-edged sword; they function only with specific substrates or reactions and cannot accommodate complex synthesis scenarios involving multiple substrates or reaction types. Processes requiring multi-step tandem reactions often necessitate the use of various enzyme preparations, significantly increasing process complexity.
High production and usage costs
Enzyme extraction and purification are complex processes, making the production of high-purity, industrial-grade enzymes difficult and expensive. Furthermore, conventional free enzymes are often hard to separate from products in aqueous reaction systems and are typically limited to single-use applications, further driving up overall production costs.
Susceptibility to interference and difficult downstream processing
Enzyme activity is easily compromised by impurities such as heavy metals and inhibitors, while contaminating enzymes in the reaction system can trigger unintended side reactions. Additionally, the mixture of enzymes and products substantially increases the workload for downstream product separation and purification, and the mild aqueous reaction environment is prone to microbial contamination.
