# Role of Ascophyllum nodosum and Fucus vesiculosus in Improving the Stress Resistance of Lactiplantibacillus plantarum

## TL;DR

This study shows that adding brown seaweeds like Ascophyllum nodosum and Fucus vesiculosus helps Lactiplantibacillus plantarum grow faster and survive better under stressful conditions.

## Contribution

The study demonstrates that whole brown algal biomass can enhance the stress resistance of L. plantarum, offering a novel prebiotic approach for probiotic applications.

## Key findings

- Algal supplements reduced the lag phase and increased growth rates of L. plantarum at 37 °C.
- Survival under acidic conditions (pH 2.5 and 3.5) exceeded 80% after 3 hours with algal supplementation.
- L. plantarum showed improved tolerance to pepsin, trypsin, and bile salts when exposed to algal extracts.

## Abstract

The survival and efficacy of probiotic bacteria depend on their ability to grow under optimal conditions and withstand environmental stresses, and marine macroalgae are emerging as promising prebiotic sources that may enhance their viability. In this study the effect of Ascophyllum nodosum and Fucus vesiculosus supplementation (0.5% w/v) on Lactiplantibacillus plantarum was evaluated by assessing growth performance and stress resistance under different conditions, including temperatures (15, 25, 30, 37, 42 °C), pH levels (2.5, 3.5, 4.5, 6.5, 8.5), and enzymatic challenges (pepsin, trypsin, bile). Both algal supplements promoted faster initial growth between 25 and 42 °C, particularly at 37 °C, by reducing the lag phase and increasing the growth rate. Under acidic stress, survival exceeded 80% after 3 h, with significant improvements at pH 2.5 and 3.5 in the presence of seaweeds, while enzymatic assays demonstrated enhanced tolerance against pepsin, trypsin, and bile salts. Overall, supplementation with brown algal biomass provided modest but consistent benefits to L. plantarum growth and stress resistance, supporting the use of whole macroalgae as functional additives in probiotic formulations for both human and animal nutrition.