Enhancing the viability of Lactobacillus rhamnosus GG after spray drying and during storage

Abstract

Increasing knowledge about the human microbiome has led to a growing awareness of the potential of applying probiotics to improve our health. The pharmaceutical industry shows an emerging interest in pharmaceutical formulations containing these beneficial microbes, the so-called pharmabiotics. An important manufacturing step is the drying of the probiotics, as this can increase the stability and shelf life of the finished pharmabiotic product. Unfortunately, drying also puts stress on microbial cells, thus causing a decrease in viability. We aimed to examine the effect of different drying media and protective excipients on the viability of the prototype probiotic strain Lactobacillus rhamnosus GG after spray drying and during subsequent storage for 28 weeks. The presence of phosphates in the drying medium showed to have a superior protective effect, especially during long-term storage at room temperature. Addition of lactose or trehalose resulted in significantly improved survival rates after drying as well as during long-term storage for the tested excipients. Both disaccharides are characterized by a high glass transition temperature. Maltodextrin showed less protective capacities compared to lactose and trehalose in all tested conditions. The usage of mannitol or dextran resulted in sticky powders and low yields, so further testing was not possible. In addition to optimizing the viability, future research will also explore the functionality of cellular probiotic components after spray drying in order to safeguard the probiotic activity of the formulated pharmabiotics.

Lactobacilli Have a Niche in the Human Nose

“…Intervention study with L. casei AMBR2 nasal spray The L. casei AMBR2 was spray dried in a co-current system with a two-fluid nozzle (orifice diameter 1.4mm) under aseptic conditions, without addition of excipients, at an initial inlet temperature of 135 C, feed (bacterial suspension) flow rate of 7.5 mL/min, air flow rate of approx. 32.5 m 3 /h, spray flow rate of 831 L/h and constant outlet temperature of 55 C. Briefly, bacterial cells were grown to the stationary phase, harvested, and dried using a laboratory-scale air spray dryer B€ uchi,Flawil,Switzerland) (Broeckx et al, 2017). Spray-dried powder was collected from a single cyclone separator continuously throughout the process.…”

Secado por atomización de bacterias ácido lácticas: una revisión

“…Otros agentes protectores utilizados son los solutos u osmolitos compatibles [49], [55], [62], [63]; que son considerados pequeños compuestos orgánicos que no interfieren con las funciones celulares y se usan para el ajuste osmótico. Estos compuestos juegan un papel más allá del ajuste osmótico, ya que actúan en la protección de la membrana celular y proteínas durante los procesos de secado [26].…”

“…Ellos encontraron que las células de L. acidophilus NCIMB 70225 en fase estacionaria temprana presentaron tasas de supervivencia significativamente mayores que las células en fase exponencial, incluso durante el almacenamiento [48]. El 38 % de los artículos seleccionados utilizaron la etapa estacionaria de crecimiento (stationary phase) en los procesos de secado por atomización, el resto de artículos seleccionados no reportan la etapa de crecimiento en la cual se llevó a cabo los experimentos [31], [34], [49], [50], [51].…”

“…En otro estudio de almacenamiento presentado en [49], encontraron la mayor supervivencia para L. rhamnosus GG después de 28 semanas a 4℃, condición que se alcanzó en Buffer fosfato alkalino-PBS con 1,25 % de lactosa o trehalosa. Ellos sugieren que la temperatura de almacenamiento debe estar entre 10-20 ℃ menos que la temperatura de transición vítrea (Tg).…”

“…Ellos sugieren que la temperatura de almacenamiento debe estar entre 10-20 ℃ menos que la temperatura de transición vítrea (Tg). Si no se cumple esta condición la matriz experimenta un cambio del estado vítreo al fluido, donde la movilidad molecular es menos restringida, lo que es perjudicial para la viabilidad de las células de BAL [49].…”