Vault protein nanocage encapsulation technology for stabilizing sweet proteins

Overview

Natural sweet proteins such as Brazzein, Monellin, and Thaumatin offer intense sweetness with minimal calories, but their commercial use has been limited by poor stability under heat, acidic conditions, and extended storage. This technology addresses those challenges by encapsulating sweet proteins within vault protein nanocages, naturally occurring shell-like particles found in many eukaryotes including humans. Because vaults are biocompatible and naturally derived, they present minimal risk of allergenicity or regulatory complications. A yeast-based production system makes large-scale manufacturing economical and robust, positioning this approach as a practical pathway to bring stable, natural protein sweeteners to market.

Technical specifications

Key features:

• Vault nanocages are hollow, barrel-shaped protein structures that encapsulate cargo proteins through a versatile INT affinity tagging strategy
• Encapsulation preserves protein activity while significantly enhancing resistance to heat inactivation, extreme pH, and long-term storage
• Validated with model enzymes: vault-encapsulated manganese peroxidase retained over 70% activity after 70 hours at 25°C compared to less than 8% for the free enzyme, and achieved 100% phenol removal at pH 4.0 versus 30% for the free enzyme
• Vault-encapsulated laccase maintained twice the activity of free laccase after six days at 45°C
• Vault nanocages themselves showed no structural change after 30 days of storage at 25°C
• Yeast-based vault production reduces cost and complexity compared to existing methods, enabling economical scale-up
• Target sweet proteins for encapsulation include Brazzein, Monellin, and Thaumatin

Technology readiness level

The underlying vault encapsulation platform and yeast-based production method have been validated in the principal investigator's laboratory using model enzymes, demonstrating clear stability improvements under heat, acidic pH, and extended storage conditions. The current proposal is a one-year proof-of-concept study to confirm that the same benefits transfer to commercially relevant sweet proteins. Planned validation includes thermostability assays at multiple temperatures, low-pH storage testing over nine months, and sensory evaluation by a taste panel. Upon successful completion, the technology will be positioned for pilot-scale trials and partnership with food and beverage companies seeking stable natural sweetener ingredients.