Evaluating microbial contaminations of alternative heating oils

Since 2008, European and German legislative initiatives for climate protection and reduced dependency on fossil resources led to the introduction of biofuels as CO₂-reduced alternatives in the heating oil sector. In the case of biodiesel, customers were confronted with accelerated microbial contaminations during storage. Since then, other fuel alternatives, like hydrogenated vegetable oils (HVOs), gas-to-liquid (GtL) products, or oxymethylene ether (OME) have been developed. In this study, we use online monitoring of microbial CO₂ production and the simulation of onset of microbial contamination to investigate the contamination potential of fuel alternatives during storage. As references, fossil heating oil of German refineries are used. Biodiesel blends with fossil heating oils confirmed the promotion of microbial activity. In stark contrast, OMEs have an antimicrobial effect. The paraffinic Fischer–Tropsch products and biogenic hydrogenation products demonstrate to be at least as resistant to microbial contamination as fossil heating oils despite allowing a diversity of representative microbes. Through mass spectrometry, elemental analysis, and microbial sequencing, we can discuss fuel properties that affect microbial contaminations. In summary, novel, non-fossil heating oils show clear differences in microbial resistance during long-term storage. Designing blends with an intrinsic resistance against microbial contamination and hence reduced activity might be an option.     

Caloplaca sect.Xanthoriella,sect. nov.: Untersuchungen über die „Xanthoria lobulata-Gruppe“ (Lichenes,Teloschistaceae)

Reexamination ofXanthoria persica, X. polycarpoides, X. lobulata gave evidence, that the thalli of these species are devoid of a lower cortex and rhizinae. Therefore, they do not fit the definition of the genusXanthoria and are transferred toCaloplaca (under the new sectionXanthoriella) asCaloplaca persica, C. polycarpoides, andC. boulyi, respectively. — Details on development, anatomical structure, ecology and distribution are presented.

     

Stabilization of cyclohexanone monooxygenase by computational and experimental library design

Enzymes often by far exceed the activity, selectivity, and sustainability achieved with chemical catalysts. One of the main reasons for the lack of biocatalysis in the chemical industry is the poor stability exhibited by many enzymes when exposed to process conditions. This dilemma is exemplified in the usually very temperature-sensitive enzymes catalyzing the Baeyer–Villiger reaction, which display excellent stereo- and regioselectivity and offer a green alternative to the commonly used, explosive peracids. Here we describe a protein engineering approach applied to cyclohexanone monooxygenase from Rhodococcus sp. HI-31, a substrate-promiscuous enzyme that efficiently catalyzes the production of the nylon-6 precursor ε-caprolactone. We used a framework for rapid enzyme stabilization by computational libraries (FRESCO), which predicts protein-stabilizing mutations. From 128 screened point mutants, approximately half had a stabilizing effect, albeit mostly to a small degree. To overcome incompatibility effects observed upon combining the best hits, an easy shuffled library design strategy was devised. The most stable and highly active mutant displayed an increase in unfolding temperature of 13°C and an approximately 33x increase in half-life at 30°C. In contrast to the wild-type enzyme, this thermostable 8x mutant is an attractive biocatalyst for biotechnological applications.     

Development of personal pollen information—the next generation of pollen information and a step forward for hay fever sufferers

Pollen allergies affect a large part of the European population and are considered likely to increase. User feedback indicates that there are difficulties in providing proper information and valid forecasts using traditional methods of aerobiology due to a variety of factors. Allergen content, pollen loads, and pollen allergy symptoms vary per region and year. The first steps in challenging such issues have already been undertaken. A personalized pollen-related symptom forecast is thought to be a possible answer. However, attempts made thus far have not led to an improvement in daily forecasting procedures. This study describes a model that was launched in 2013 in Austria to provide the first available personal pollen information. This system includes innovative forecast models using bi-hourly pollen data, traditional pollen forecasts based on historical data, meteorological data, and recent symptom data from the patient’s hayfever diary. Furthermore, it calculates the personal symptom load in real time, in particular, the entries of the previous 5 days, to classify users. The personal pollen information was made available in Austria on the Austrian pollen information website and via a mobile pollen application, described herein for the first time. It is supposed that the inclusion of personal symptoms will lead to major improvements in pollen information concerning hay fever sufferers.     

Hospital profiling using Bayesian decision theory

For evaluating the quality of care provided by hospitals, special interest lies in the identification of performance outliers. The classification of healthcare providers as outliers or non-outliers is a decision under uncertainty, because the true quality is unknown and can only be inferred from an observed result of a quality indicator. We propose to embed the classification of healthcare providers into a Bayesian decision theoretical framework that enables the derivation of optimal decision rules with respect to the expected decision consequences. We propose paradigmatic utility functions for two typical purposes of hospital profiling: the external reporting of healthcare quality and the initiation of change in care delivery. We make use of funnel plots to illustrate and compare the resulting optimal decision rules and argue that sensitivity and specificity of the resulting decision rules should be analyzed. We then apply the proposed methodology to the area of hip replacement surgeries by analyzing data from 1,277 hospitals in Germany which performed over 180,000 such procedures in 2017. Our setting illustrates that the classification of outliers can be highly dependent upon the underlying utilities. We conclude that analyzing the classification of hospitals as a decision theoretic problem helps to derive transparent and justifiable decision rules. The methodology for classifying quality indicator results is implemented in an R package (iqtigbdt) and is available on GitHub.     

The Temperature Gradient-Forming Device,an Accessory Unit for Normal Light Microscopes To Study the Biology of Hyperthermophilic Microorganisms

To date, the behavior of hyperthermophilic microorganisms in their biotope has been studied only to a limited degree; this is especially true for motility. One reason for this lack of knowledge is the requirement for high-temperature microscopy—combined, in most cases, with the need for observations under strictly anaerobic conditions—for such studies. We have developed a custom-made, low-budget device that, for the first time, allows analyses in temperature gradients up to 40°C over a distance of just 2 cm (a biotope-relevant distance) with heating rates up to ∼5°C/s. Our temperature gradient-forming device can convert any upright light microscope into one that works at temperatures as high as 110°C. Data obtained by use of this apparatus show how very well hyperthermophiles are adapted to their biotope: they can react within seconds to elevated temperatures by starting motility—even after 9 months of storage in the cold. Using the temperature gradient-forming device, we determined the temperature ranges for swimming, and the swimming speeds, of 15 selected species of the genus Thermococcus within a few months, related these findings to the presence of cell surface appendages, and obtained the first evidence for thermotaxis in Archaea.     

EphrinB2 and GRIP1 stabilize mushroom spines during denervation-induced homeostatic plasticity

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