Author(s): Machado, Daniela ; Vedor, Rita ; Fonseca, Mariana ; Sousa, Sérgio ; Barbosa, Joana Cristina ; Carvalho, Nelson Mota de ; Costa, Célia Maria ; Madureira, Ana Raquel ; Gomes, Ana Maria
Date: 2025
Persistent ID: http://hdl.handle.net/10400.14/55664
Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
Objective: Akkermansia muciniphila is a next-generation probiotic recognized for improving gut barrier function and metabolic health. However, ensuring its viability during processing, storage, and gastrointestinal transit remains a challenge. This study investigated calcium-alginate encapsulation as a strategy for enhancing the stability of A. muciniphila during refrigerated aerobic storage and gastrointestinal passage as well as biological validation in an in vitro fecal model. Methods: A. muciniphila was encapsulated using an extrusion technique with 2% (m/v) sodium alginate and 4% (m/v) calcium chloride. Viability of free and encapsulated cells was assessed over 28-days of refrigerated aerobic storage. Gastrointestinal stability was evaluated using the INFOGEST protocol. In vitro colonic fermentation was conducted in healthy and Escherichia coli O157:H7-infected fecal samples. Microbial composition was analyzed via metagenomic sequencing, while microbial metabolism was assessed by ammonia quantification and short- chain fatty acids (SCFA) profile analysis. Results: Encapsulation achieved a 60% yield and preserved high probiotic viability (at levels around 8-log CFU/g) during 28- days of storage. Moreover, encapsulated cells exhibited higher survival when exposed to gastrointestinal conditions compared to free cells. In fecal fermentation assays, encapsulated A. muciniphila enhanced microbial diversity, reduced Escherichia genus abundance, and modulated SCFA profile. Furthermore, an increasing trend in ammonia production until the 30-hour mark, followed by a decline suggests potential ammonia assimilation by the probiotic. Conclusions: Calcium-alginate encapsulation is a promising delivery strategy to improve the viability and functionality of A. muciniphila, supporting its use as a live biotherapeutic agent for modulating gut microbiota and intestinal infections mitigation.
