Fungal β-Glucans Enhance Lactic Acid Bacteria Growth by Shortening Their Lag Phase and Increasing Growth Rate

The gut microbiome has a significant role in general health and well-being. Novel types of prebiotics, such as fungal polysaccharides, show potential for the formulation of new synbiotic formulations. However, little is known about the underlying mechanisms of the prebiotic effects of such compounds. This study investigated the prebiotic properties of fungal glucan extracts from Pleurotus ostreatus, Lentinula edodes, and Saccharomyces cerevisiae, employing a novel high-throughput method based on optical density measurements. This approach enabled the simultaneous screening of the effects of multiple extracts on six different strains of probiotic bacteria. Experiments were conducted to evaluate the effect of the extracts on the growth dynamics (the duration of the lag phase and the growth rate) of probiotic strains of the genera Lactobacillus and Lacticaseibacillus and on pathogenic bacteria. Fungal polysaccharide supplementation, particularly with their β-glucans, significantly shortened the lag phase by an average of 7-8 h in all tested strains and increased the growth rate by 2-fold in four strains of lactic acid bacteria. Different magnitudes of effects were observed across the various strain-extract combinations. This study lays the groundwork for elucidating the mechanism by which fungal β-glucans stimulate growth in probiotic bacteria and for the rapid screening of optimal combinations for formulating innovative synbiotics.