Fungal Territory

ISOLATION OF WILD YEAST FOR POTENTIAL USE IN BEER PRODUCTION

Mon, 20 Dec 2021 00:00:00 +0100

There is a limited amount of yeast strains that are currently used in industrial beer brewing. Wild yeasts could provide an alternative to common domesticated brewer’s yeasts by offering a new range of sensory characteristics and improved performance in harsh brewing conditions such as high gravity and high ethanol concentration in wort. High gravity brewing is practical and profitable as it increases production capacity, therefore reducing investment and energy costs. Exploiting the existing natural diversity could lead to finding superior industrial yeasts as well as a better understanding of biodiversity. The aim of the present study was to determine if wild yeast strains isolated from the ecosystem at a regional level (Northeast Mexico) showed favorable characteristics in the brewing process. Sixty-three yeast isolates were obtained from diverse samples including flowers and fruits. Five isolates were selected after three rounds of beer fermentation based on their sensory characteristics. Tests to assess growth over time, flocculation potential, ethanol yield, osmotolerance and ethanol tolerance were applied to two reference yeasts (commercial beer brewing strains) and to the selected isolates of interest which were identified as Saccharomyces cerevisiae by MEX67 amplification and ITS sequencing. The results indicated that the selected wild isolates exhibit characteristics comparable to commercial reference strains in terms of growth and stress tolerance.

PHYSICOCHEMICAL PROPERTIES AND BIOLOGICAL ACTIVITIES OF MANGO (MAGNIFERA INDICA L.) SEED KERNEL AND PEEL OILS

Zekeria Yusuf, Alemtsehay Malede, Mulugeta Desta, Megersa Idris, Sultan Seyida — Mon, 20 Dec 2021 00:00:00 +0100

The peel and kernels mango (Mangifera indica L.) processing by products can be used as a source of valuable products. Therefore, the present study was attempted to study physicochemical properties, antioxidant and antimicrobial activities of mango seed kernel and peel wastes. The result of physicochemical properties indicated that significantly higher oil yield (38.75±1.77), specific gravity (0.86±0.04), acid value (2.66±0.20) and free fatty acid value (1.34±0.12); and higher DPPH (16.70±0.70) antioxidant activities were recorded for mango seed oil extract. However, significantly higher hydrogen peroxide scavenging activity (HPSA, 31.10±1.70) and ascorbic acid (43.00±2.73) were recorded for fruit peel oil extract. Stronger antibacterial activity with maximum zone of inhibition (16.50 mm), minimum inhibitory concentration MIC (0.10µl/ml) and corresponding minimum bactericidal concentration MBC (0.20 µl/ml) was recorded for seed oil extract against S. aureus. Stronger antifungal activity with maximum zone of inhibition (16.47 mm), MIC (0.05 µl/ml, the least value) and MFC (0.10 µl/ml) for seed oil extract against C. albicans. It can be concluded from the results of present study that seed oil extract was found to be more effective antioxidant and antimicrobial potential than peel oil extract in mango (M. indica L.)