Solving Enzyme Stability by Tackling Glycerol-Free Formulation Challenges

Imagine diagnostic assays that can be shipped and stored at room temperature, removing the need for freezing or refrigeration while maintaining stability and performance—even in remote areas.

Molecular diagnostics, known for their unparalleled sensitivity and specificity, are at the forefront of disease detection and play a critical role in timely healthcare decisions worldwide. However, the field still faces formidable logistical challenges: traditional liquid reagents require cold-chain management, a costly and complex necessity that limits accessibility, especially in low-resource settings.

The Role of Glycerol

Traditionally, enzyme buffers use glycerol as a cryoprotectant and stabilizer to prevent ice crystal formation that could damage enzymes when stored at -20°C¹. A 50% glycerol buffer lowers the freezing point to -23°C², allowing enzymes to be stored at -20°C without undergoing damaging freeze/thaw cycles³. However, glycerol’s ability to lower the freezing point also makes water removal during the freeze-drying process challenging, potentially leaving residual moisture⁴ that can compromise the quality of lyophilized products intended for ambient-temperature shipping and storage.

Glycerol can be removed from enzyme buffers using dialysis or filtration, but these methods are time-consuming and can change the salt concentration, leading to up to 20% enzyme loss⁵. Additionally, once glycerol is removed, extensive process optimization and quality control are needed to ensure the enzyme’s stability and functionality in the modified buffer. Therefore, the best approach for developing reagents suited for lyophilization, air-drying, and ambient-temperature stability is to formulate them without glycerol from the start. However, designing stable, glycerol-free formulations remain a significant challenge, requiring careful selection of stabilizers and other excipients that can protect the enzyme’s structure and activity. These stabilizers must not only preserve enzyme function during storage and use but also be compatible with downstream applications, ensuring consistent performance across different assay conditions. Deep expertise in enzymology and buffer optimization, combined with extensive screening, formulation optimization, and accelerated stability studies, is essential for successfully designing high-performing glycerol-free enzymes.

With over 40 years of innovation in reagent development, Meridian has engineered high-performing glycerol-free enzymes for PCR, LAMP, and NGS. These enzymes are designed to retain superior activity and stability after lyophilization, ensuring reliable performance across a range of molecular diagnostic applications.

Meridian also offers its expertise through custom formulation services, assisting in the conversion of existing enzyme formulations to glycerol-free versions. With a collaborative and flexible approach, Meridian provides assay developers with direct access to its deep knowledge of enzymology, enabling the rapid optimization of existing assay protocols or the development of new protocols incorporating lyophilized reagents.

Meridian’s Glycerol-Free Enzymes

A critical first step in creating a glycerol-free enzyme is using highly purified material, which is achieved through careful purification and strict quality control. Meridian’s extensive expertise in advanced buffer formulation allows for precise fine-tuning of the concentration of each component in the buffer, including magnesium, salts, PCR enhancers, and stabilizers. This optimization ensures that the buffer chemistry is tailored for each glycerol-free enzyme, resulting in optimal enzyme activity and full compatibility with lyophilization.