Saccharomyces boulardii is a unique species of yeast previously characterized as a probiotic strain (CNCM I-745) among a few probiotic yeasts reported to date. Inulin is one of the most common prebiotics that exhibit twisted hydrocolloidal properties in dairy products. The present study was designed to develop a synbiotic yogurt by incorporation of S. boulardii and inulin at 1%, 1.5%, and 2% (w/v), comparing with the probiotic and control plain yogurts. Microrheological, microstructural, microbiological, sensory properties, and volatile compounds of the yogurt samples were evaluated. Microrheological analysis showed that addition of inulin to yogurt slightly reduced the values of G′ and G″, while solid–liquid balance (SLB) values confirmed more solid properties of the synbiotic yogurt (0.582~0.595) than the plain yogurt (0.503~0.518). A total of 18 volatile compounds were identified in the synbiotic yogurt, while only five and six compounds were identified in plain and probiotic yogurts, respectively. Physiochemical parameters such as pH, acidity, and protein content were in the normal range (as with the control), while fat content in the synbiotic yogurt decreased significantly. Addition of 1% inulin not only reduced syneresis but also maintained viability of S. boulardii after 28 days of storage. Microstructural and microrheological studies confirmed the dense, compressed, homogeneous structure of the synbiotic yogurt. Thus, addition of inulin improved the textural and sensory properties of the synbiotic yogurt, as well as survival of S. boulardii with viable count above 6.0 log CFU/g in yogurt, as generally required for probiotics. Therefore, novel synbiotic yogurt with desirable quality was developed as an effective carrier for delivery of the probiotic yeast exerting its beneficial health effects.

Folate deficiency is accompanied by gut dysbacteriosis.

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The widespread and indiscriminate use of broad-spectrum antibiotics leads to microbial resistance, which causes major problems in the treatment of infectious diseases. However, advances in nanotechnology have opened up new domains for the synthesis and use of nanoparticles against multidrug-resistant pathogens. The traditional approaches for nanoparticle synthesis are not only expensive, laborious, and hazardous but also have various limitations. Therefore, new biological approaches are being designed to synthesize economical and environmentally friendly nanoparticles with enhanced antimicrobial activity. The current study focuses on the isolation, identification, and screening of metallotolerant fungal strains for the production of silver nanoparticles, using antimicrobial activity analysis and the characterization of biologically synthesized silver nanoparticles by X-ray diffraction (XRD) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). In total, 11 fungal isolates were isolated and screened for the synthesis of AgNPs, while the Penicillium notatum (K1) strain was found to be the most potent, demonstrating biosynthetic ability. The biologically synthesized silver nanoparticles showed excellent antibacterial activity against the bacteria Escherichia coli (ATCC10536), Bacillus subtilis, Staphylococcus aureus (ATCC9144), Pseudomonas aeruginosa (ATCC10145), Enterococcus faecalis, and Listeria innocua (ATCC13932). Furthermore, three major diffraction peaks in the XRD characterization, located at the 2θ values of 28.4, 34.8, 38.2, 44, 64, and 77°, confirmed the presence of AgNPs, while elemental composition analysis via EDX and spherical surface topology with a scanning electron microscope indicated that its pure crystalline nature was entirely composed of silver. Thus, the current study indicates the enhanced antibacterial capability of mycologically synthesized AgNPs, which could be used to counter multidrug-resistant pathogens.

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