An Electro-Microbial Process to Uncouple Food Production from Photosynthesis for Application in Space Exploration.

Here we propose the concept of an electro-microbial route to uncouple food production from photosynthesis, thereby enabling production of nutritious food in space without the need to grow plant-based crops. In the proposed process, carbon dioxide is fixed into ethanol using either chemical catalysis or microbial carbon fixation, and the ethanol created is used as a carbon source for yeast to synthesize food for human or animal consumption. The process depends upon technologies that can utilize electrical energy to fix carbon into ethanol and uses an optimized strain of the yeast to produce high-quality, food-grade, single-cell protein using ethanol as the sole carbon source in a minimal medium.

Crucial aspects of metabolism and cell biology relating to industrial production and processing of biomass.

The multitude of applications to which spp. are put makes these yeasts the most prolific of industrial microorganisms. This review considers biological aspects pertaining to the manufacture of industrial yeast biomass.

Techno-economic implications of improved high gravity corn mash fermentation.

The performance of Saccharomyces cerevisiae MBG3964, a strain able to tolerate >18% v/v ethanol, was compared to leading industrial ethanol strain, Fermentis Ethanol Red, under high gravity corn mash fermentation conditions. Compared to the industrial ethanol strain, MBG3964 gave increased alcohol yield (140g L(-1) vs. 126g L(-1)), lower residual sugar (4g L(-1) vs.

Use of population genetics to derive nonrecombinant Saccharomyces cerevisiae strains that grow using xylose as a sole carbon source.

According to scientific dogma, Saccharomyces cerevisiae cannot grow utilizing xylose as a sole carbon source. Although recombinant DNA technology has overcome this deficiency to some degree, efficient utilization of xylose appears to require complex global changes in gene expression. This complexity provides a significant challenge to the development of yeasts suitable for the utilization of xylose-rich lignocellulosic substrates.

Involvement of oxidative stress response genes in redox homeostasis, the level of reactive oxygen species, and ageing in Saccharomyces cerevisiae.

Saccharomyces cerevisiae mutants lacking oxidative stress response genes were used to investigate which genes are required under normal aerobic conditions to maintain cellular redox homeostasis, using intracellular glutathione redox potential (glutathione E(h)) to indicate the redox environment of the cells. Levels of reactive oxygen species (ROS) and mitochondrial membrane potentials (MMP) were also assessed by FACS using dihydroethidium and rhodamine 123 as fluorescent probes. Cells became more oxidised as strains shifted from exponential growth to stationary phase.

A flow-cytometric method for determination of yeast viability and cell number in a brewery.

A flow-cytometric assay, using the fluorescent dye, oxonol, for the simultaneous determination of yeast cell viability and cell number is described. The assay was optimised, and trialed at a brewery for 6 months. The flow-cytometry assay offered a substantially reduced error in viability determination, compared to methylene blue which is the industry standard for measuring viability.

Inducible gene expression by nonculturable bacteria in milk after pasteurization.

The viability of bacteria in milk after heat treatments was assessed by using three different viability indicators: (i) CFU on plate count agar, (ii) de novo expression of a gfp reporter gene, and (iii) membrane integrity based on propidium iodide exclusion. In commercially available pasteurized milk, direct viable counts, based on dye exclusion, were significantly (P < 0.05) higher than viable cell counts determined from CFU, suggesting that a significant subpopulation of cells in pasteurized milk are viable but nonculturable.