BIOTALK: "Strategies to promote next generation probiotics viability and stability under stress conditions"

Aud. EBI (-101)

Speaker: Daniela Machado | Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal

Abstract
In recent years, the scientific community has been widening their knowledge about dynamics involved in metabolic and inflammatory disorders. The prevalence of these conditions are reaching epidemic proportions, bringing new challenges to clinicians and researchers. The specific roles and modulating properties that beneficial/probiotic bacteria hold in the context of the gut ecosystem seem to be a key strategy to avert such imbalances. Currently, Akkermansia muciniphila, Faecalibacterium prausnitzii and Eubacterium hallii have emerged as potential next generation probiotics (NGP) given their demonstrated potential in prevention and treatment of inflammatory/cardio-metabolic disorders. The challenges of these non-conventional native gut bacteria lie mainly on their sensitivity to aerobic environments, which precludes the development of nutraceutical and therapeutic formulations. In this line of research supported by the EOSBAC and CAPEOSBAC projects, we intend to develop strategies to enhance the viability and stability of NGPs under stress conditions, including aerobic storage and gastrointestinal (GI) passage. The initial steps toward the achievement of such goals have been performed using A. muciniphila and will be the focus of this biotalk. Asides a comprehensive phenotypic characterization of A. muciniphila DSM 22959, exposure to ambient air resilience, adhesion properties viability and stability when incorporated in different formulations or encapsulated and submitted to both GI transit and aerobic storage will be covered. Exposure essays to ambient air revealed that A. muciniphila survived up to 72 hours in an aerobic atmosphere. In addition, the adhesion properties of A. muciniphila to gut epithelium were proven, using Caco-2 and HT29-MTX cell lines as in vitro models. Then, freeze-dried formulations and encapsulation methods were explored as technological strategies to enhance viability and stability of A. muciniphila when submitted to both GI transit and aerobic storage. Overall, A. muciniphila achieved high numbers in freeze-dried powders of the formulation containing inulin (10 % w/v), riboflavin (16.5 mM) and glutathione (0.2 % w/v). In addition, this formulation contained higher number of viable cells than the starch counterpart, yet the addition of starch conferred higher stability during aerobic storage. In an attempt to reduce sensitivity to GI and aerobic storage conditions, A. muciniphila was encapsulated, by emulsification/internal gelation method, in a Na-alginate (4 % w/v), calcium carbonate (CaCO3; 500 mM) and denatured whey protein isolate (DWPI; 10 % w/v). Akkermansia muciniphila was efficiently encapsulated, where microcapsules size diameter was smaller than 100 μm. Moreover, encapsulated A. muciniphila demonstrated high resistance to GI conditions and aerobic storage since their viability only decreased 1 log cycle after simulated GI tract exposure presenting a high stability after 7 days of refrigerated aerobic storage. These findings suggest Na-alginate:CaCO3:DWPI microcapsules reveal a potential strategy to protect A. muciniphila against detrimental GI transit and aerobic storage conditions.

Acknowledgments: This work was supported by national funds through FCT/MEC (PIDDAC), project reference IF/00588/2015 and by Operational Program Competitiveness and Internationalization in its FEDER component and by the budget of the Foundation for Science and Technology, I.P. (FCT, IP) in its OE component, project reference POCI-01-0145-FEDER-031400 (PTDC/BAA-AGR/31400/2017) with scientific collaboration of CBQF under the FCT project UID/Multi/50016/2019.