Saccharomyces cerevisiae in the production of fermented beverages

Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively) strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre‐hydrolysis) in the case of beers and whiskies, sucrose‐rich plants (molasses or sugar juice from sugarcane) in the case of rums, or from fruits (which do not require pre‐hydrolysis) in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites) as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations

Temporal trend in the transfer of Sellafield-derived 14C into different size fractions of the carbonate component of NE Irish Sea sediment

From 1994 onwards, 14C discharges from the Sellafield nuclear fuel reprocessing plant have been made largely to the Northeast Irish Sea. They represent the largest contributor to UK and European populations of the collective dose commitment derived from the entire nuclear industry discharges. Consequently, it is important to understand the long-term fate of 14C in the marine environment. Research undertaken in 2000 suggested that the carbonate component of Northeast Irish Sea sediments would increase in 14C activity as mollusc shells, which have become enriched in Sellafield-derived 14C, are broken down by physical processes including wave action and incorporated into intertidal and sub-tidal sediments. The current study, undertaken in 2011, tested this hypothesis. The results demonstrate significant increases in 14C enrichments found in whole mussel shells compared to those measured in 2000. Additionally, in 2000, there was an enrichment above ambient background within only the largest size fraction (>500 μm) of the intertidal inorganic sediment at Nethertown and Flimby (north of Sellafield). In comparison, the present study has demonstrated 14C enrichments above ambient background in most size fractions at sites up to 40 km north of Sellafield, confirming the hypothesis set out more than a decade ago

Positive Diagnosis of Ancient Leprosy and Tuberculosis Using Ancient DNA and Lipid Biomarkers

Diagnosis of leprosy and tuberculosis in archaeological material is most informative when based upon entire genomes. Ancient DNA (aDNA) is often degraded but amplification of specific fragments also provides reliable diagnoses. Cell wall lipid biomarkers can distinguish ancient leprosy from tuberculosis and DNA extraction residues can be utilized. The diagnostic power of combined aDNA and lipid biomarkers is illustrated by key cases of ancient leprosy and/or tuberculosis. Human tuberculosis was demonstrated in a woman and child from Atlit-Yam (~9 ka) in the Eastern Mediterranean and in the 600 BCE Egyptian “Granville” mummy. Both aDNA and lipids confirmed Pleistocene tuberculosis in a ~17 ka bison from Natural Trap Cave, Wyoming. Leprosy is exemplified by cases from Winchester (10th–12th centuries CE) and Great Chesterford (5th–6th centuries CE). A mixed infection from Kiskundorozsma, Hungary (7th century CE) allowed lipid biomarkers to assess the relative load of leprosy and tuberculosis. Essential protocols for aDNA amplification and analysis of mycolic, mycolipenic, mycocerosic acid, and phthiocerol lipid biomarkers are summarized. Diagnoses of ancient mycobacterial disease can be extended beyond the reach of whole genomics by combinations of aDNA amplification and lipid biomarkers, with sole use of the latter having the potential to recognize even older cases

Hybrid natural inflation from non Abelian discrete symmetry

A spontaneously broken global discrete symmetry may have pseudo Goldstone modes associated with the spontaneous breaking of the approximate continuous symmetry of the low dimension terms in the Lagrangian. These provide natural candidates for an inflaton that can generate slow roll inflation. We show that, in the case of a non Abelian discrete symmetry, the pseudo Goldstone modes readily couple to further scalar fields in a manner that the end of inflation is determined by these additional scalar fields, generating hybrid inflation. We give a simple parameterisation of the inflationary potential in this case, determine the inflationary parameters resulting, and show that phenomenological successful inflation is possible while keeping the scale of symmetry breaking sub-Plankian. Unlike natural inflation the inflation scale can be very low. We construct two simple hybrid inflation models, one non supersymmetric and one supersymmetric. In the latter case no parameters need be chosen anomalously small.Comment: Accepted for publication in Phys. Lett.

Enhanced Crystallographic incorporation of Strontium(II) ions to Calcite via Preferential Adsorption at Obtuse growth steps

Sr-containing calcium carbonates were precipitated from solutions containing Ca(OH)₂, SrCl₂ and Na₂CO₃ in a reactor where constant solution composition was maintained. The total concentration of divalent ions was same in all experiments, but the Sr/Ca ratio was varied between 0.002 and 0.86, and the pH value was between 12.02 and 12.25. All solutions were oversaturated with respect to calcite (SIcalcite = 1.2-1.5). Calcite was the only product formed at low Sr/Ca ratios, but at Sr/Ca ≥ 0.45 strontianite was detected in some systems. Sr-rich precipitate was observed in both a surface layer on (6.9-6 µm) rhombic calcite seed crystals and as smaller (> 3.64-1.96 µm) calcite crystals that were elongated along their C-axis. The degree of crystal elongation increased with the Sr/Ca ratio in those crystals. Precipitates recovered from low Sr/Ca ratio experiments exhibited an XRD spectrum identical to that of rhombic calcite, however the peaks attributed to Sr-containing calcite shifted progressively to lower 2θ values with increasing solution Sr/Ca ratio, indicating increased lattice volume. Sr K-edge EXAFS analysis of the precipitates showed that the shift in morphology and lattice volume is accompanied by a change in the local coordination of Sr²⁺ in calcite. The Sr-O bond lengths were similar to the Ca-O bond lengths in calcite, but Sr-O coordination increased from 6 fold in crystals containing 0.21 Wt. % Sr, to 8 fold in crystals containing 9.47 Wt. % Sr, and the Sr-Ca coordination decreased from 6 and 6 (for the first and second Sr-Ca shells respectively) to 4 and 1. It is suggested that Sr²⁺ undergoes preferential incorporation at obtuse (+) growth sites on the calcite surface due to its large ionic radius (1.13 Å), and this increases the growth rate parallel to the C-axis, resulting in the observed elongation in this direction

Hybrid Natural Low Scale Inflation

We discuss the phenomenological implications of hybrid natural inflation models in which the inflaton is a pseudo-Goldstone boson but inflation is terminated by a second scalar field. A feature of the scheme is that the scale of breaking of the Goldstone symmetry can be lower than the Planck scale and so gravitational corrections are under control. We show that, for supersymmetric models, the scale of inflation can be chosen anywhere between the Lyth upper bound and a value close to the electroweak breaking scale. Unlike previous models of low scale inflation the observed density perturbations and spectral index are readily obtained by the choice of the free parameters