Supplement-Free Cultivation of Saccharomyces cerevisiae var. boulardii Using Sunflower Meal Hydrolysate

Abstract

This study evaluated sunflower meal, a protein- and carbohydrate-rich by-product of sunflower oil processing, as a sustainable feedstock for the supplement-free cultivation of Saccharomyces cerevisiae var. boulardii. Sequential acid and enzymatic hydrolysis were applied to release fermentable sugars. During this process, the formation of fermentation inhibitors, such as hydroxymethyl furfural (HMF) and furfural, was also monitored. Hydrolysates were analyzed by high-performance liquid chromatography over 72 h to determine sugar profiles and inhibitor concentrations. The selected hydrolysis conditions yielded up to 25.76 g/L glucose, whereas HMF and furfural concentrations remained relatively low, ranging from 0.09 to 0.52 g/L and 0.02 to 0.11 g/L, respectively. The resulting hydrolysate was evaluated as a cultivation medium for S. cerevisiae var. boulardii under submerged fermentation conditions (30 °C, 120 rpm) without additional nutrient supplementation. Viable cell counts reached 8.3–8.4 log CFU/mL, comparable to those obtained in a yeast extract-peptone-malt extract (YPM) control medium. The sunflower meal hydrolysate exhibited substantially higher antioxidant activity than YPM throughout the cultivation period, with high initial values indicating a major contribution from sunflower-derived compounds. These findings demonstrate that sunflower meal can be converted into a hydrolysate with relatively low HMF and furfural concentrations that supports substantial S. cerevisiae var. boulardii growth. The resulting fermentation broth also exhibited high antioxidant activity, highlighting the potential of sunflower meal hydrolysate as a sustainable alternative medium for probiotic yeast production.