Lyophilization of Listeria Strains Using Composite Matrices
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Solution Overview
Problem
Lyophilization of Listeria bacteria strains, such as Listeria monocytogenes, is challenging due to strain-specific parameters and the complexity of the freeze-drying process, which can result in cell damage and reduced viability.
Innovation Solution
A method for lyophilizing bacteria or Listeria strains involving a formulation with a buffer and sucrose, followed by a freezing step, primary drying under vacuum at a temperature between −10° C. and −30° C., and secondary drying at a temperature between −5° C. and 25° C., to produce a stable lyophilized composition with residual moisture between 2.5% and 4% and high viability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If lyophilization is used to preserve bacteria, then storage stability and shelf-life are improved, but cell damage and loss of viability occur
Solution Approach 1:
The patent applies preliminary action by pre-freezing the bacterial composition at controlled rates before lyophilization. This pre-freezing step prepares the bacterial cells and formulation matrix in advance, creating a protective ice crystal structure and concentrating protective agents around the cells before the drying process begins, thereby reducing cell damage during subsequent sublimation
Solution Approach 2:
The patent employs parameter changes by optimizing multiple lyophilization parameters including freezing temperature (−50°C to −80°C), primary drying temperature (−30°C to −10°C), secondary drying temperature (20°C to 40°C), and pressure conditions. These parameter adjustments create optimal conditions that balance water removal efficiency with bacterial cell protection, maintaining viability while achieving long-term stability
2Reliability
If traditional liquid formulations are used, then bacterial viability is maintained, but storage and transportation costs increase due to cold-chain requirements
Solution Approach 1:
The patent utilizes phase transitions by converting the bacterial formulation from liquid to solid lyophilized state through controlled freezing and sublimation. This phase change removes the need for cold-chain storage while preserving bacterial viability through the protective effects of the frozen matrix and optimized drying process, enabling room temperature storage and reducing energy costs
Solution Approach 2:
The patent employs composite materials by formulating bacteria with protective excipients including sugars (sucrose, trehalose), amino acids (glycine, alanine), and buffers in the lyophilized matrix. This composite formulation provides multiple protective functions simultaneously: structural support, moisture control, and cell membrane protection, enabling stable storage without refrigeration while maintaining high viability
3Reliability
If strain-specific optimized freeze-drying procedures are developed, then cell viability is improved, but the process becomes more complex and laborious
Solution Approach 1:
The patent applies universality by developing a standardized lyophilization protocol and formulation platform that can be applied across multiple bacterial strains including Listeria monocytogenes, Salmonella, and E. coli. The core formulation components (sugars, amino acids, buffers) and processing parameters serve universal protective functions, reducing the need for strain-specific optimization while maintaining high viability through the multi-protective composite matrix
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves high viability (>60%) of Listeria strains after storage at −20° C. or 4° C. for up to 24 months, reducing storage and transportation costs and enabling room temperature stability, thus overcoming the limitations of traditional liquid formulations.
Implementation Method 1
cooling the composition provided in step (a) to a holding temperature between about −32° C. and about −80° C. in a freezing step
Implementation Method 2
exposing the composition produced by step (b) to a vacuum at a holding temperature between about −10° C. and about −30° C. in a primary drying step
Implementation Method 3
exposing the composition produced by step (c) to a vacuum at a holding temperature between about −5° C. and about 25° C. in a secondary drying step
Data Source
AI summary
Methods and compositions are provided for lyophilization of bacteria or Listeria strains, such as Listeria monocytogenes. Provided are methods for producing a lyophilized composition comprising a bacteria or Listeria strain, formulations for lyophilization comprising a bacteria or Listeria strain, lyophilized bacteria or Listeria strains, and methods of preparing frozen bacteria or Listeria strains for lyophilization.