Avaliação do crescimento de Saccharomyces boulardii utilizando permeado hidrolisado do soro de leite

Abstract

Probiotics are live microorganisms that provide health benefits to the host and play an essential role in maintaining the balance of the intestinal microbiota. Among them, the yeast Saccharomyces boulardii, a subspecies of Saccharomyces cerevisiae, stands out and has been widely studied for its probiotic characteristics. This yeast has proven effective in the treatment and prevention of gastrointestinal disorders, such as antibiotic-associated diarrhea, Clostridium difficile infections, and inflammatory bowel diseases. As an alternative to conventional cultivation media, studies have demonstrated the use of whey permeate as a promising substrate, offering a sustainable and low-cost option, in addition to adding value to a by-product of the dairy industry. Whey permeate is rich in lactose and mineral salts but poses a significant environmental impact when improperly discarded. In this context, this study aimed to evaluate the cultivation of S. boulardii using whey permeate as a substrate, through the assessment of different enzymatic hydrolysis conditions of lactose and the subsequent fermentation process. In the lactose hydrolysis step, different concentrations of the enzyme β-galactosidase (Saphera® 2600 L) and processing temperatures were tested, based on a 2² factorial design, with the goal of optimizing the process. According to the results, the best condition was observed at 35 °C and 0.15% (w/v) enzyme concentration, with 31.9% lactose conversion and the release of 50.9 g L⁻¹ of glucose. This condition was used for the hydrolysis of the permeate, which then served as the cultivation medium for the yeast, resulting in a final biomass concentration of 6.81 g L⁻¹ after 30 hours of fermentation. At the end of the process, the following fermentation parameters were observed: biomass productivity (QX) of 0.223 g L⁻¹·h⁻¹, substrate-to-biomass conversion factor (YX/S) of 0.140 g·g⁻¹, and maximum specific growth rate (µmax) of 0.321 h⁻¹. The results confirm the feasibility of using whey permeate as an alternative and low-cost substrate with potential for agroindustrial waste valorization, highlighting its sustainable use for probiotic biomass production.