In vivo instability of chorismate causes substrate loss during fermentative production of aromatics

Metabolic engineering of microbial strains to produce aromatic compounds deriving from the shikimate pathway is of great interest to the chemical industry as a more sustainable alternative for feedstock production. Chorismate is a significant intermediate in the shikimate pathway. In this study, the formation of phenylalanine and phenylpyruvate as by‐products in strains engineered downstream of the chorismate node for increased aromatic production was explored in yeast fermentations. Tracer experiments showed that these compounds are synthesized de novo during fermentation, under conditions in which their synthesis was genetically blocked. Chorismate stability evaluation, as well as deletion mutation analysis throughout the phenylalanine biosynthesis pathway, suggested that this synthesis was a result of intracellular, non‐enzymatic rearrangement of chorismate to phenylpyruvate via prephenate, which was followed by enzymatic transamination of phenylpyruvate to form phenylalanine. These results not only aid in the development of strain‐engineering strategies to avoid the accumulation of by‐products during fermentations aimed at increased aromatics production, but also deepen our understanding of yeast metabolism. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation of plasma,high‐pressure and ultrasound processing on the stability of fructooligosaccharides

Fructooligosaccharides (FOS) are among the main carbohydrates with prebiotic activity, and they are the most applied functional carbohydrate ingredient in the food industry. FOS are known to hydrolyse when subjected to thermal processing, thus partially losing its functional properties. In this study, we evaluate whether three nonthermal technologies are suitable for processing FOS regarding its stability after processing. FOS were subjected to ultrasound, high‐pressure processing (HPP) and atmospheric cold plasma (ACP). The FOS solution, 70 g L^?1, was set at a concentration recommended for human intake. The treatments were carried out at operating conditions usually used for microbial inactivation in foods (HPP at 450 MPa for 5 min; US at 600–1200 W L^?1 for 5 min; ACP at 70 kV for 15–60 s). NMR and HPLC analysis of the FOS components showed that ACP, ultrasound and HPP have not induced any significant change on FOS concentration (<2.0%) nor on the degree of polymerisation of the FOS (<3.3%). Contrarily to what is reported for thermal treatments, these nonthermal technologies were considered suitable for FOS processing.     

Behaviour of pseudo-random and chaotic sources of stochasticity in nature-inspired optimization methods

Stochasticity, noisiness, and ergodicity are the key concepts behind many natural processes and its modeling is an important part of their implementation. There is a handful of soft-computing methods that are directly inspired by nature or stochastic natural processes. The implementation of such a nature-inspired optimization and search methods usually depends on streams of integer and floating point numbers generated in course of their execution. The pseudo-random numbers are utilized for in-silico emulation of probability-driven natural processes such as arbitrary modification of genetic information (mutation, crossover), partner selection, and survival of the fittest (selection, migration) and environmental effects (small random changes in motion direction and velocity). Deterministic chaos is a well known mathematical concept that can be used to generate sequences of seemingly random real numbers within selected interval in a predictable and well controllable way. In the past, it has been used as a basis for various pseudo-random number generators (PRNGs) with interesting properties. This work provides an empirical comparison of the behavior of selected nature-inspired optimization algorithms using different PRNGs and chaotic systems as sources of stochasticity.     

Magnetic behavior of CeO<Subscript>2-δ</Subscript> thin films doped with non-magnetic transition metals

This paper presents the magnetic behavior of CeO_2-δ films doped with two non-magnetic transition metal elements: copper and zinc. High quality films were grown on LaAlO₃ (001) substrate using a pulsed laser deposition technique. Detailed structural characterization and magnetic property measurements were performed. Our results showed that Cu-doped CeO_2-δ films exhibit room temperature ferromagnetism while Zn-doped CeO_2-δ films are non-magnetic.     

Effect of production season on protein fraction content in milk of various breeds of goats in Poland

Milk of various goat breeds was analysed to assess the effect of production season on content of basic chemical components, with regard to whey proteins. Milk of goats in the productive herds (white and coloured coat) contained significantly (P < 0.01) more total protein, casein, fat, dry matter and functional whey proteins. The production season significantly determined the content of total protein (P < 0.01), casein (P < 0.01) and whey proteins (P < 0.05), including α‐lactalbumin (P < 0.01) and lactoferrin (P < 0.01). A higher content of total protein and casein was found in the autumn–winter season and the content of whey proteins was higher in the spring–summer period.     

Heat recovery stamp charged coke making: An experience in operational excellence

The coal blend quality and process control of coke making technologies is an important lever to produce quality coke with optimal cost. Apart from impacting cost, this improves the CO₂ footprint. This is facilitated by proper selection of coke making technologies and coal/coal blend. Each technology has its own advantage and limitation based on its design criteria. Recently, Tata Steel introduced Asia largest single location 1.6 mtpa of heat recovery coke plant for the first time. This paper briefly described the operational philosophy evolved in heat recovery coke plant to produce desired quality coke at comparatively lower cost through operational excellence. The reduction of imported prime hard coking coal in coal blend up to 30% without affecting coke quality adversly and understanding the operational processes and finally mastering heat recovery coke making technology was also part of this paper.