Anti-bacterial activity of lysozyme in pitching yeast and effect of lysozyme on yeast fermentation

Lysozyme has antibacterial activity against Gram-positive bacteria and has no activity against yeast. As such, lysozyme can be used for the specific inhibition of beer spoilage bacteria. After all, the most frequently identified beer spoilage bacteria are lactic acid bacteria and brewers’ yeast is the culture used for the fermentation. Hen egg white lysozyme (300 mg/L) is tested for the antibacterial activity against four described Gram-positive beer spoilage bacteria in industrial pitching yeast and in industrial beer with refermentation in the bottle. The influence of industrial pitching yeast treated with lysozyme on the fermentation performance is also studied

Determinants of euro term structure of credit spreads

In this paper, we investigate the determinants of the Euro term structure of credit spreads. More specifically, we analyze whether the sensitivity of credit spread changes to financial and macroeconomic variables depends on bond characteristics such as rating and maturity. According to the structural models and empirical evidence on credit spreads, we find that changes in the level and the slope of the default-free term structure, the market return, implied volatility, and liquidity risk significantly influence credit spread changes. The effect of these factors strongly depends on bond characteristics, especially the rating and to a lesser extent the maturity. Bonds with lower ratings are more affected by financial and macroeconomic news. Furthermore, we find that liquidity risk significantly increases credit spreads, especially on lower rated bonds. JEL Classification: C22, E45, G15Credit risk, Nelson-Siegel, Structural models

The Term Structure of Credit Spreads on Euro Corporate Bonds

Although there is a broad literature on structural credit risk models, there has been little empirical testing of these models.In this paper we examine the term structure of credit spreads on euro corporate bonds and the empirical validation of structural credit risk models.The latter provide a framework to analyze the main determinents of credit spreads.Using a dataset of 1577 investment grade corporate and 250 AAA rated government bonds, we first estimate the term structure of credit spreads for di.erent (sub)rating categories with an extension of the Nelson-Siegel method.Within each rating category, credit spreads on plus rated bonds have significantly higher credit spreads than minus rated bonds.According to the structural models, the results indicate that credit spread changes are significantly negatively correlated with changes in the level and the slope of the default-free term structure.While changes in the slope a.ect all rating categories, changes in the level are more important for higher rated bonds (AAA and AA).The stock return and the implied volatility of the stock price seem to significantly influence credit spread changes.The lower the rating category and the longer the maturity of the bond the stronger both e.ects.For BBB rated bonds, changes in liquidity -measured as the bid-ask spread- significantly influence credit spread changes.Higher rated bonds (AAA and AA) are also driven by past credit spread changes.capital markets;risk management;bonds;volatility;credit risk

Application of Mn(III) Oxidative Cyclizations to Natural Product Synthesis

This work begins with a brief review of manganese(III) acetate free radical oxidative cyclization chemistry and its application toward functionalizing nitrogen containing heterocycles. Exploration of a cyclopropane ring opening reaction using indoline, and subsequent manganese(III) cyclization chemistry will be presented as a possible route towards a family of natural products called the flinderoles. Work on the construction of the core of several indole alkaloids from the genus Tabernaemontana, including tronocarpine, chippiine, and dippinine B, will be explored with utilization of manganese(III) cyclizations. Hopes of accessing an advanced common intermediate for each of these natural products will be discussed due to structural similarities that converge nicely with the use of manganese(III) as a key synthetic step

2D separation and profiling of complex oligosaccharide mixtures

Oligosaccharides present in various natural sources can contain different linkages, susbstitutions and building blocks with the same mass. Oligosaccharide mixtures often contain these isomeric and isobaric structures, which causes their complexity. These components are difficult to separate and analyze with conventional analytical methods. The technique described below was developed to obtain a higher resolution

Spectrum of polysaccharides degradation products of ales and lager beers

The saccharide spectrum, as a distribution of fractions of different molecular mass, of sixteen beers was determined by ultracentrifugation using filters with cut-offs of 1, 5, 10 and 50 kDa. The saccharide concentrations in the filtrates were determined by density measurements. The saccharide composition was examined through HPAEC-PAD. The results were compared with the values of classic features of beers. The newly developed method provides additional information of the beers and is a simple and fast tool for exploring the effect of the saccharide spectrum on the industrial characteristics. The results revealed that similar top fermentation beers and similar lager beers have different saccharide spectra