Differential distribution and proteomic response of Saccharomyces cerevisiae and non‐model yeast species to zinc

Efficient Mycoprotein Production with Low CO2 Emissions through Metabolic Engineering and Fermentation Optimization of Fusarium venenatum

The global protein shortage is intensifying, and promising means to ensure daily protein supply are desperately needed. The mycoprotein produced by Fusarium venenatum is a good alternative to animal/plant-derived protein. To comprehensively improve the mycoprotein synthesis, a stepwise strategy by blocking the byproduct ethanol synthesis and the gluconeogenesis pathway and by optimizing the fermentation medium was herein employed. Ultimately, compared to the wild-type strain, the synthesis rate, carbon conversion ratio, and protein content of mycoprotein produced from the engineered strain were increased by 57% (0.212 vs 0.135 g/L·h), 62% (0.351 vs 0.217 g/g), and 57% (61.9 vs 39.4%), respectively, accompanied by significant reductions in CO2 emissions. These results provide a referential strategy that could be useful for improving mycoprotein synthesis in other fungi; more importantly, the obtained high-mycoprotein-producing strain has the potential to promote the development of the edible protein industry and compensate for the gap in protein resources.

Effects of ultrasound treatments on wine microorganisms

Ultrasound is one of the most promising non-thermal an emerging technique in food technology. The objective of the present work was to evaluate the effect of different ultrasonic treatments on the most important wine microbiota (Saccharomyces and non-Saccharomyces yeasts and lactic acid bacteria). Two stages were carried out: the assessment step, where six different ultrasonic treatments (with varying power, time, and pulses) were used on Saccharomyces cerevisiae, Brettanomyces spp., and Lactiplantibacillus plantarum; and the validation step, where two chosen ultrasonic treatments were used on Zigosaccharomyces bailli, Brettanomyces spp., Saccharomyces cerevisiae, Saccharomyces bayanus, Pichia membranifaciens, Schizosaccharomyces pombe, and Hanseniaspora osmophila. The most sensitive microorganism was Brettanomyces spp., and the most resistant was Lactiplantibacillus plantarum. Ultrasonic treatments had varying effects on vitality (delay of growth or maximum OD reduction) and on viability (reduction of microbial growth).

Proteomic profiling and glycomic analysis of the yeast cell wall in strains with Aflatoxin B1 elimination ability

The use of microorganisms for Aflatoxin B₁ elimination has been studied as a new alternative tool and it is known that cell wall carried out a critical role. For that reason, cell wall and soluble intracellular fraction of eight yeasts with AFB₁ detoxification capability were analysed. The quantitative and qualitative comparative label-free proteomic allowed the identification of diverse common constituent proteins, which revealed that putative cell wall proteins entailed less than 10% of the total proteome. It was possible to characterize different enzymes linked to cell wall polysaccharides biosynthesis as well as other proteins related with the cell wall organization and regulation. Additionally, the concentration of the principal polysaccharides was determined which permitted us to observe that β-glucans concentration was higher than mannans in most of the samples. In order to better understand the biosorption role of the cell wall against the AFB₁ , an antimycotic (Caspofungin) was used to damage the cell wall structure. This assay allowed the observation of an effect on the normal growth of those yeasts with damaged cell walls that were exposed to AFB₁ . This effect was not observed in yeast with intact cell walls, which may reveal a protective role of this structure against mycotoxins.