Bench scale Layer-by-Layer microencapasulation of Lactiplantibacillus plantarum WCFS1.

Layer-by-Layer (LbL) self-assembly encapsulation is a promising technology for the protection and delivery of lactic acid bacteria. However, laboratory-scale encapsulation is often time-consuming, involves intensive protocols tailored for small-scale operations, requires substantial amounts of energy and water, and results in a low yield of encapsulated biomass. Scaling-up this process to a bench-bioreactor scale is not simply a matter of increasing culture volume as different key parameters (not particularly relevant at lab scale) become critical, including biomass production, the number of polymer layers, and the biomass-to-polymer mass ratio.

Investigation of Freezing and Freeze-Drying for Preserving and Re-Using a Whole Microbial Cheese Community.

Preserving microbial ecosystems obtained from traditional cheese-making processes is crucial to safeguarding the biodiversity of microbial cheese communities and thus ensuring that the high flavor quality of traditional cheeses is maintained. Few protocols have been proposed for the long-term storage of microbial consortia. This work aimed to develop preservation methods to stabilize the entire microbial community in smear-ripened cheese without multiplication or isolation.

Mechanistic study of the differences in lactic acid bacteria resistance to freeze- or spray-drying and storage.

Lactobacillus delbrueckii subsp. bulgaricus and Lactiplantibacillus plantarum are two lactic acid bacteria (LAB) widely used in the food industry. The objective of this work was to assess the resistance of these bacteria to freeze- and spray-drying and study the mechanisms involved in their loss of activity.

Insights into the mechanisms of L. salivarius CECT5713 resistance to freeze-dried storage.

Ligilactobacillus salivarius is a lactic acid bacterium exhibiting several health benefits. However, it is sensitive to freeze-drying and storage in the dried state, thus limiting its commercial exploitation. Our objective was to identify markers of cell resistance by applying multiscale characterization to L.

Multiobjective optimization of frozen and freeze-dried Lactobacillus delbrueckii subsp. bulgaricus CFL1 production via the modification of fermentation conditions.

Aim: This study investigates the individual and combined effects of fermentation parameters for improving cell biomass productivity and the resistance to freezing, freeze-drying, and freeze-dried storage of Lactobacillus delbrueckii subsp. bulgaricus CFL1.

Methods And Results: Cells were cultivated at different temperatures (42°C and 37°C) and pH values (5.

Effect of protective agents on the storage stability of freeze-dried Ligilactobacillus salivarius CECT5713.

Ligilactobacillus salivarius is a lactic acid bacterium exhibiting several health benefits but remains commercially underexploited due to its inability to survive during long-term storage in the dried state. Our objective was to study the effect of various protective molecules (maltodextrin, trehalose, antioxidants, and fructooligosaccharides), being efficient on other bacteria, on the freeze-dried stability of L. salivarius CECT5713.

Insights into lactic acid bacteria cryoresistance using FTIR microspectroscopy.

Freezing is widely used for bacterial cell preservation. However, resistance to freezing can greatly vary depending on bacterial species or growth conditions. Our study aims at identifying cellular markers of cryoresistance based on the comparison of three lactic acid bacteria (LAB) exhibiting different tolerance to freezing: Carnobacterium maltaromaticum CNCM I-3298, Lactobacillus delbrueckii subsp.

Dynamic Modeling of CNCM I-3298 Growth and Metabolite Production and Model-Based Process Optimization.

is a species of lactic acid bacteria found in dairy, meat, and fish, with technological properties useful in food biopreservation and flavor development. In more recent years, it has also proven to be a key element of biological time-temperature integrators for tracking temperature variations experienced by perishable foods along the cold-chain. A dynamic model for the growth of CNCM I-3298 and production of four metabolites (formic acid, acetic acid, lactic acid, and ethanol) from trehalose in batch culture was developed using the reaction scheme formalism.

Heat Transfer During Freeze-Drying Using a High-throughput vial System in view of Process Scale-up to Serum vials.

Specific devices that combine 96-well plates and high-throughput vials were recently proposed to improve the efficiency of formulation screening. Such devices make it possible to increase the number of formulations tested while reducing the amount of active ingredients needed. The geometry of the product container influences the heat and mass transfer during freeze-drying, impacting product temperature (T_{p}) and therefore affecting the final product quality.

Highlighting Protective Effect of Encapsulation on Yeast Cell Response to Dehydration Using Synchrotron Infrared Microspectroscopy at the Single-Cell Level.

In the present paper, the Layer by Layer (LbL) method using β-lactoglobulin and sodium alginate was performed to individually encapsulate cells in microorganized shells in order to protect them against stresses during dehydration. Higher survival (∼1 log) for encapsulated yeast cells was effectively observed after air dehydration at 45°C. For the first time, the potentiality of Synchrotron-Fourier Transform InfraRed microspectroscopy (S-FTIR) was used at the single-cell level in order to analyze the contribution of the biochemical composition of non-encapsulated vs.

FTIR micro-spectroscopy using synchrotron-based and thermal source-based radiation for probing live bacteria.

Fourier transform infrared (FTIR) spectroscopy has proven to be a non-invasive tool to analyse cells without the hurdle of employing exogenous dyes or probes. Nevertheless, the study of single live bacteria in their aqueous environment has long remained a big challenge, due to the strong infrared absorption of water and the small size of bacteria compared to the micron-range infrared wavelengths of the probing photons. To record infrared spectra of bacteria in an aqueous environment, at different spatial resolutions, two setups were developed.

Freeze-Drying of Lactic Acid Bacteria: A Stepwise Approach for Developing a Freeze-Drying Protocol Based on Physical Properties.

Freeze-drying or lyophilization has become a reference process for preserving lactic acid bacteria. The development of stable freeze-dried lactic acid bacteria (LAB) requires maintaining the biological activity of the cells and the macroscopic porous structure while increasing the efficiency of the manufacturing process. Physical properties of protective solutions, such as glass transition and collapse temperatures, are key elements not only for process optimization but also for the stability of freeze-dried LAB.

Factors influencing the membrane fluidity and the impact on production of lactic acid bacteria starters.

Production of lactic acid bacteria starters for manufacturing food, probiotic, and chemical products requires the application of successive steps: fermentation, concentration, stabilization, and storage. Despite process optimization, losses of bacterial viability and functional activities are observed after stabilization and storage steps due to cell exposure to environmental stresses (thermal, osmotic, mechanical, and oxidative). Bacterial membrane is the primary target for injury and its damage is highly dependent on its physical properties and lipid organization.

Determination of the dried product resistance variability and its influence on the product temperature in pharmaceutical freeze-drying.

During the primary drying step of the freeze-drying process, mass transfer resistance strongly affects the product temperature, and consequently the final product quality. The main objective of this study was to evaluate the variability of the mass transfer resistance resulting from the dried product layer (R) in a manufacturing batch of vials, and its potential effect on the product temperature, from data obtained in a pilot scale freeze-dryer. Sublimation experiments were run at -25 °C and 10 Pa using two different freezing protocols: with spontaneous or controlled ice nucleation.

Effect of Freeze Dryer Design on Heat Transfer Variability Investigated Using a 3D Mathematical Model.

During the freeze-drying process, vials located at the border of the shelf usually present higher heat flow rates that result in higher product temperatures than vials in the center. This phenomenon, referred to as edge vial effect, can lead to product quality variability within the same batch of vials and between batches at different scales. Our objective was to investigate the effect of various freeze dryer design features on heat transfer variability.

Subcellular membrane fluidity of Lactobacillus delbrueckii subsp. bulgaricus under cold and osmotic stress.

Cryopreservation of lactic acid bacteria may lead to undesirable cell death and functionality losses. The membrane is the first target for cell injury and plays a key role in bacterial cryotolerance. This work aimed at investigating at a subcellular resolution the membrane fluidity of two populations of Lactobacillus delbrueckii subsp.

Biophysical characterization of the Lactobacillus delbrueckii subsp. bulgaricus membrane during cold and osmotic stress and its relevance for cryopreservation.

Freezing lactic acid bacteria often leads to cell death and loss of technological properties. Our objective was to provide an in-depth characterization of the biophysical properties of the Lactobacillus delbrueckii subsp. bulgaricus membrane in relation to its freeze resistance.

Determination of Intracellular Vitrification Temperatures for Unicellular Micro Organisms under Conditions Relevant for Cryopreservation.

During cryopreservation ice nucleation and crystal growth may occur within cells or the intracellular compartment may vitrify. Whilst previous literature describes intracellular vitrification in a qualitative manner, here we measure the intracellular vitrification temperature of bacteria and yeasts under conditions relevant to cryopreservation, including the addition of high levels of permeating and nonpermeating additives and the application of rapid rates of cooling. The effects of growth conditions that are known to modify cellular freezing resistance on the intracellular vitrification temperature are also examined.

Draft Genome Sequence of Lactobacillus delbrueckii subsp. bulgaricus CFL1, a Lactic Acid Bacterium Isolated from French Handcrafted Fermented Milk.

Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) is a lactic acid bacterium widely used for the production of yogurt and cheeses.

Understanding the cryotolerance of lactic acid bacteria using combined synchrotron infrared and fluorescence microscopies.

Freezing is widely used for preserving different types of cells. Frozen concentrates of lactic acid bacteria (LAB) are extensively used for manufacturing food, probiotic products and for green chemistry and medical applications. However, the freezing and thawing processes cause cell injuries that result in significant cell death.

Freeze-drying of lactic acid bacteria.

Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g.

Model for heat and mass transfer in freeze-drying of pellets.

Lyophilizing frozen pellets, and especially spray freeze-drying, have been receiving growing interest. To design efficient and safe freeze-drying cycles, local temperature and moisture content in the product bed have to be known, but both are difficult to measure in the industry. Mathematical modeling of heat and mass transfer helps to determine local freeze-drying conditions and predict effects of operation policy, and equipment and recipe changes on drying time and product quality.

Effect of product temperature during primary drying on the long-term stability of lyophilized proteins.

Our objective was to investigate the effect of performing primary drying at product temperatures below and above Tg' (glass transition temperature of the freeze-concentrated phase) on the long-term stability of lyophilized proteins. Two protective media differing in the nature of the bulking agent used (amorphous or crystalline) were selected. Several lyophilization cycles were performed by using various combinations of shelf temperature and chamber pressure to obtain different values of product temperature during primary drying.