The potential role of yeasts in the mitigation of health issues related to beer consumption

Unraveling the potential nutritional benefits of fermented date syrup waste: Untargeted metabolomics and carbohydrate metabolites of in vitro digested fraction

Valorization of fruit by-products is a crucial area of research for the development of innovative bio-based products. This study investigated the physicochemical properties and health-promoting benefits of date syrup waste, both fermented by Pichia cecembensis or Pichia kudriavzevii (FDSW), and unfermented (CDSW). Metabolomics profiles of these samples were identified post in vitro digestion. FDSW exhibited 42 volatile compounds, including 9 new ones, and contained (-)-epicatechin, tyrosol, and gallic acid. Bioaccessible fractions of FDSW demonstrated substantial α-amylase inhibition, with percentages of 40.7 % and 53.9 %, respectively. FDSW displayed superior cytotoxicity against Caco2 and MCF-7 cancer cell lines, with an average of ∼75 % and 56 %, respectively. Untargeted metabolomics analysis revealed an increase in secondary metabolites, totaling 27 metabolites. LC-QTOF analysis of bioaccessible carbohydrate metabolites in FDSW identified two phytochemical groups, alkaloids, and terpenoids. This study underscores the potential of FDSW for producing value-added bio-based products with desirable characteristics and health benefits.

Scale-up and fed-batch cultivation strategy for the enhanced co-production of microbial lipids and carotenoids using renewable waste feedstock

Agro-industrial by-product valorization as a feedstock for the bioproduction of high-value products has demonstrated a feasible alternative to handle the environmental impact of waste. Oleaginous yeasts are promising cell factories for the industrial production of lipids and carotenoids. Since oleaginous yeasts are aerobic microorganisms, studying the volumetric mass transfer (k_La) could facilitate the scale-up and operation of bioreactors to grant the industrial availability of biocompounds. Scale-up experiments were performed to assess the simultaneous production of lipids and carotenoids using the yeast Sporobolomyces roseus CFGU-S005 and comparing the yields in batch and fed-batch mode cultivation using agro-waste hydrolysate in a 7 L bench-top bioreactor. The results indicate that oxygen availability in the fermentation affected the simultaneous production of metabolites. The highest production of lipids (3.4 g/L) was attained using the k_La value of 22.44 h^-1, while higher carotenoid accumulation of 2.58 mg/L resulted when agitation speed was increased to 350 rpm (k_La 32.16 h^-1). The adapted fed-batch mode in the fermentation increased the production yields two times. The fatty acid profile was affected according to supplied aeration and after the fed-batch cultivation mode. This study showed the scale-up potential of the bioprocess using the strain S. roseus in the obtention of microbial oil and carotenoids by the valorization of agro-industrial byproducts as a carbon source.