Influence of Must Supplementation on Growth of Pediococcus spp. after Alcoholic Fermentation

One factor potentially affecting growth of wine spoilage microbes (e.g., Pediococcus spp.) is the presence of nutrients not consumed during alcoholic fermentation by Saccharomyces cerevisiae. To assess the impactof must nutrient supplementation on Pediococcus spp., synthetic grape musts containing low (55.2 mg N/L), medium (250 mg N/L), or high (530 mg N/L) concentrations of yeast assimilable nitrogen (YAN) were fermented by S. cerevisiae. Upon cessation of fermentative activity P. damnosus OW-2, P. inopinatus OW-8, P. parvulus WS-7C, WS-29A, OW-1, or P. pentosaceus ATCC 33316 were inoculated at 104 to 105 cfu/mL. With the exceptions of OW-1 and OW-2, none of the other species or strains grew in the synthetic wines unless yeast extract or peptone was added, suggesting the absence of an essential nutrient.  Experiments were replicated using Cabernet Sauvignon musts containing low (66.9 mg N/L), medium(219 mg N/L), and high (438 mg N/L) YAN. In general, wines containing the greatest residual amino acid concentrations (high YAN) supported better growth of the aforementioned Pediococcus spp. However, low YAN wines containing negligible residual nitrogen achieved similar populations after a short period of initial inhibition, suggesting that ‘excessive’ nitrogen supplementation to musts does not have a large impact on growth of pediococci post alcoholic fermentation

The Value of Grid-Scale Variable Renewable Energy Generation in Sub-Saharan Africa

This report was produced for the Green Growth Diagnostics for Africa project, funded by the Engineering and Physical Sciences Research Council.Securing a sufficient supply of reliable and affordable electricity is a huge challenge for countries in sub-Saharan Africa. Many countries in the region are experiencing rapid increases in the size of their populations, and even more rapid growth in their economies. As a result, the region experienced a 45 per cent increase in annual energy consumption between the years 2000-2014, with the growth in some countries much higher. This article surveys the most relevant research, policies and sources of data relevant to generation adequacy assessment in two example SSA countries: Kenya and Ghana. It also includes an exploratory analysis of the temporal relationships between the hydro resource, wind resource and power demand in Kenya, with an emphasis on assessing the impact of limited data availability

Capillary membrane-immobilised polyphenol oxidase and the bioremediation of industrial phenolic effluent

Waste-generating industrialisation is intrinsically associated with population and economic proliferation. This places considerable emphasis on South Africa's water shortage due to the integral relationship between population growth rate and infrastructure development. Of the various types of industry-generated effluents, those containing organic pollutants such as phenols are generally difficult to remediate. Much work has been reported in the literature on the use of enzymes for the removal of phenols from these waste-streams but little application of this bioremediation approach has reached practical fruition. This study focuses on integrating and synergistically combining the advantages of enzyme-mediated dephenolisation of synthetic and industrial effluent with that of membrane teclmology. The ability of the enzyme polyphenol oxidase to convert phenol and a number of its derivatives to chemically reactive o-quinones has been reported extensively in the literature. These o-quinones can then physically be removed from solution using various precipitation or adsorption techniques. The enzyme is, however, plagued by a product-induced phenomenon known as suicide inactivation, which renders it inactive and thus limits its application as a bioremediation tool. Integrating membrane technology with the enzyme's catalytic ability by immobilising polyphenol oxidase onto polysulphone and poly(ether sulphone) capillary membranes enabled the physical removal of these inhibitory products from the micro-environment of the immobilised enzyme which therefore increased the phenol conversion capability of the immobilised biocatalyst. Under non-immobilised conditions it was found that when exposed to a mixture of various phenols the substrate preference of the enzyme is a function of the R-group. Under immobilised conditions, however, the substrate preference of the enzyme becomes a function of certain transport constraints imposed by the capillary membrane itself. Furthermore, by integrating a quinone-removal process in the enzyme-immobilised bioreactor configuration, a 21-fold increase in the amount of substrate converted per Unit enzyme was observed when compared to the conversion capacity of the inunobilised enzyme without the product removal step. Comparisons were also made using different membrane bioreactor configurations (orientating the capillaries transverse as opposed to parallel to the module axis) and different immobilisation matrices (poly(ether sulphone) and polysulphone capillary membranes). Conversion efficiencies as high as 77% were maintained for several hours using the combination of transverse-flow modules and novel polysulphone capillary membranes. It was therefore concluded that immobilisation of polyphenol oxidase on capillary membranes does indeed show considerable potential for future development

Historic Farmsteads: Preliminary Character Statement - North East region

This document is one of eight Preliminary Character\ud Statements, which provide information on the\ud characteristics of traditional farm buildings in each\ud Region

The magnetic Bp star 36 Lyncis, I. Magnetic and photospheric properties

This paper reports the photospheric, magnetic and circumstellar gas characteristics of the magnetic B8p star 36 Lyncis (HD 79158). Using archival data and new polarised and unpolarised high-resolution spectra, we redetermine the basic physical properties, the rotational period and the geometry of the magnetic field, and the photospheric abundances of various elements.}{Based on magnetic and spectroscopic measurements, we infer an improved rotational period of $3.83475\pm 0.00002$ d. We determine a current epoch of the longitudinal magnetic field positive extremum (HJD 2452246.033), and provide constraints on the geometry of the dipole magnetic field (i\geq 56\degr, $3210 {\rm G}\leq B_{\rm d}\leq 3930$ G, $\beta$ unconstrained). We redetermine the effective temperature and surface gravity using the optical and UV energy distributions, optical photometry and Balmer line profiles ($T_{\rm eff}=13300\pm 300$ K, $\log g=3.7-4.2$), and based on the Hipparcos parallax we redetermine the luminosity, mass, radius and true rotational speed ($L=2.54\pm 0.16 L_\odot, M=4.0\pm 0.2 M_\odot, R=3.4\pm 0.7 R_\odot, v_{\rm eq}=45-61.5$ \kms). We measure photospheric abundances for 21 elements using optical and UV spectra, and constrain the presence of vertical stratification of these elements. We perform preliminary Doppler Imaging of the surface distribution of Fe, finding that Fe is distributed in a patchy belt near the rotational equator. Most remarkably, we confirm strong variations of the H$\alpha$ line core which we interpret as due to occultations of the star by magnetically-confined circumstellar gas.Comment: Accepted by Astronomy and Astrophysic

Recent studies of magnetic fields in Herbig Ae/Be stars

New determinations of the mean longitudinal magnetic field for several Herbig Ae/Be stars are presented. The longitudinal magnetic field measurements of MWC 480 reveal the presence of a strong kG field, which was undetected in our previous low‐resolution polarimetric observations with FORS 1. The magnetic field geometries of Herbig Ae/Be stars studied with spectropolarimetric time series can likely be described by centred dipoles with polar magnetic field strengths of several hundred Gauss. A number of Herbig Ae/Be stars with detected magnetic fields were recently observed with X‐shooter in the visible and near‐IR as well as with the high‐resolution near‐IR spectrograph CRIRES. These observations are of great importance to understand the relation between the magnetic field topology and the physics of accretion flow and accretion disk gas emission (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89448/1/1022_ftp.pd