Proteome modulation in microencapsulated Lactobacillus reuteri DSM 17938 during simulated gastrointestinal conditions (SGC)

Probiotics have known in recent years an important rediscovery and re-evaluation. Many studies that have been conducted by numerous research groups have highlighted their fundamental role in maintaining our health and well-being and the prevention of certain diseases. However, as living microorganisms they can also be partially destroyed during production, storage and even from the stomach acid environment. Several technological approaches have been proposed to overcome this problem and microencapsulation has gained a great attention because of its potentiality in enhancing their capability to resist to several environmental stress factors[1]. However at this moment are almost lacking experimental evidences that describe the effects of microencapsulation on protein modulation of probiotic bacteria as well as the effect of this protection during SGC. In this work, our aim is to investigate through a gel-based proteomic approach proteome dynamics of chitosan-alginate encapsulated Lactobacillus reuteri DSM 17938 during SGC. Overnight cultures of L. reuteri DSM17938 were encapsulated in core-shell microcapsules[2]. Free and encapsulated bacteria were incubated in ratio 1:4 in gastric simulated solution for 2h at 37 °C and subsequently for 3h at 37 °C in intestinal simulated solution. After incubation bacterial protein have been extracted as described[3] and separated by 1D and 2D electrophoresis. Differentially expressed spot between free and encapsulated bacteria after SGC (p<0.05) have been detected using Progenesis Same Spot 4.6 and will be identified by MALDI-TOF/TOF MS. Several significant differences have been highlighted between the different experimental conditions. The identification of the proteins modulated during SGC in free and encapsulated bacteria will shed light on metabolic response of probiotic bacteria to physiological and technological stress factors.