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The electricity network is undergoing a change due to reducing costs for renewable energy sources. Subsidy programs for renewable energy sources are changing and the funding available is being reduced. This will have an impact on anaerobic digestion which in some cases may struggle financially. Overfeeding is one of the most common mechanisms of inhibition in the process, and by shifting to intermittent feeding for on-demand production, this change will provide more information about the digestion process and could be used to detect the beginning of inhibition due to overfeeding. This paper discusses the shift towards intermittent production and how this change can be used to monitor the anaerobic digestion process.
The introduction of Feed-in tariffs in the German Renewable Energy Act (EEG) fuelled the growth of anaerobic digestion (AD) industry making Germany the country with highest number of operational AD plants. However, the rapid expansion of AD industry resulted in some unwanted side-effects such as food vs fuel debate, increased prices for electricity and the temporal mismatch between supply and demand of electricity grid. Subsequent amendments in EEG has tried to address some of these issues by reduction in Feed-in tariffs, introduction of a cap on cereal based feedstocks and providing premium for energy production in accordance with market demand. Furthermore, the Feed-in tariffs which were introduced for 20 years are soon going to expire. The changes in legal and political discourse is soon going to introduce some new challanges to the AD industry. This paper has discussed some of these challanges and their potential solutions.
Pseudozyma antarctica Lipase B catalyzed esterification and transesterification in deep eutectic solvents (DES) was investigated in reaction systems with alcohols of different polarity. Coconut oil and crude biodiesel were deacidified successfully with non-immobilized CALBL and final acid values of 1.2 for biodiesel and 0.5 for coconut oil were obtained, while no esterification with ethanol was observed without DES. Water depletion of the lipid phase in the presence of water adsorbing DES causes this difference. Analysis of water contents revealed a 10 fold lower water content of the lipid phase in the presence of a second DES phase than in trials without utilization of DES. In contrast reactions of hydrophilic polyols are suppressed in the presence of DES. While the esterification of fructose and the transesterification with glycerol worked well in the polar solvent 2-methyl-2-butanol, almost no fructose esterification and a decreased transesterification with glycerol were observed in the presence of DES. Analysis of logP values of the substrates explains the substrate dependent differences in reactivity. The polar alcohols are probably bound strongly in the hydrogen-bonding network of the DES phase and are thus not available for lipase catalyzed reactions.
In the last few decades raw material molasses, used in large scale fermentations in the production of bioethanol, citric acid, (baker´s) yeast and yeast extracts, has become more and more expensive. That is why agro-industrial wastes have become an interesting alternative. They are being produced in large volumes every day and represent a serious environmental problem considering its high organic content. The present contribution aims to demonstrate how waste products of wine production can be employed as substrate in bioethanol production. Cultivation of yeast and bioethanol production on molasses and grape pomace extract was studied in flasks in laboratory scale. This work should be regarded as an example of integrated sustainability which demonstrates how the waste from one industrial process is used as feedstock for another.
Comparative analysis of non-natural acceptor glucosylation with sucrase enzymes of family GH 70
(2019)
Mutan- and alternansucrase were analyzed for their non-natural glucosylation potential with catecholic compounds caffeic acid and nordihydroguaiaretic acid (NDGA) as well as with non-catecolic p-coumaric acid and umbellic acid. Mutansucrase accepted both catecholic substrates and high glucosylation yields of 92 % with caffeic acid and 81 % with NDGA were obtained. The enzyme showed a clear regio-preference for the catechol 4-OH, which corresponds to findings from our previous work with Leuconostoc and Weissella derived glucansucrases. The substrate spectrum of the alternansucrase was broader and all substrates were successfully glucosylated with a preference for the catechols. Interestingly alternansucrase possessed a different regio-specificity. With caffeic acid the 3-O-α-D-glucoside was the major product. A similar substrate spectrum and regioselectivity pattern was observed in previous glucansucrase screenings only with glucansucrase from strain Weissella beninensis DSM 22752. Therefore it may be concluded that the W. beninensis enzyme is an alternansucrase type enzyme as well.
Multidrug resistance (MDR) in tumors and pathogens remains a major problem in the efficacious treatment of patients by reduction of therapy options and subsequent treatment failure. Various mechanisms are described to be involved in the development of MDR with overexpression of ATP-binding cassette (ABC) transporters reflecting the most extensively studied. These membrane transporters translocate a wide variety of substrates utilizing energy from ATP hydrolysis leading to decreased intracellular drug accumulation and impaired drug efficacy. One treatment strategy might be inhibition of transporter-mediated efflux by small molecules. Isocoumarins and 3,4-dihydroisocoumarins are a large group of natural products derived from various sources with great structural and functional variety, but have so far not been in the focus as potential MDR reversing agents. Thus, three natural products and nine novel 3,4-dihydroisocoumarins were designed and analyzed regarding cytotoxicity induction and inhibition of human ABC transporters P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) in a variety of human cancer cell lines as well as the yeast ABC transporter Pdr5 in Saccharomyces cerevisiae. Dual inhibitors of P-gp and BCRP and inhibitors of Pdr5 were identified, and distinct structure-activity relationships for transporter inhibition were revealed. The strongest inhibitor of P-gp and BCRP, which inhibited the transporters up to 80 to 90% compared to the respective positive controls, demonstrated the ability to reverse chemotherapy resistance in resistant cancer cell lines up to 5.6-fold. In the case of Pdr5, inhibitors were identified that prevented substrate transport and/or ATPase activity with IC50 values in the low micromolar range. However, cell toxicity was not observed. Molecular docking of the test compounds to P-gp revealed that differences in inhibition capacity were based on different binding affinities to the transporter. Thus, these small molecules provide novel lead structures for further optimization.
For use in a landfill, a laboratory reactor for safe and environmentally friendly biological utilization of low-concentration methane gas will be further developed. The current principle of denitrification-coupled aerobic methane oxidation will be replaced by methane oxidation under anaerobic conditions. Anaerobic methane oxidation offers the advantage that, in addition to methane, nitrate also undergoes biodegradation. Another advantage is that the oxygen content can be significantly lower. This reduces the risk of the formation of an explosive atmosphere in the reactor. Currently, the principle of anaerobic methane oxidation is known. However, organisms capable of doing so are not yet available as a pure culture. Therefore, several biomasses were probed for the ability of anaerobic methane oxidation. It was found that moor-heavy sediment, activated sludge from the leachate treatment plant and biomass from the local biogas plant oxidize methane after the natural carbon source (C source) was been removed.
STEPsCON 2018 was jointly organized by the Faculty of Applied Natural Sciences of TH Köln (Germany) and the University of Oulu (Finland) on the occasion of the 50th anniversary of the Leverkusen – Oulu town twinning. The conference focused on sustainability issues and covered the current state of research in four key topics:
1. Sustainable Medicine and Pharmaceuticals
2. Resources and Bioremediation
3. Sustainable Chemistry & Industrial Biotechnology
4. Innovative Materials & Formulations
Due to the worldwide shortage of petrochemical based resources, the usage of renewable bio-based raw materials for established and novel products becomes increasingly important.[1] Such bio-based resources are already used for the fabrication of a variety of products, e. g. paper, lubricants, detergents or cosmetics. In the future they are expected to emerge in many more applications in industry and household.[1]
A very promising approach relies on the use of glycolipids as a source of hydroxy-oleic acid.[2] Microbial glycolipids are produced for instance via fermentation from natural resources such as plant oils and sugar.[3] After fermentation complex product mixtures are obtained with the composition depending on the microorganism, substrate and fermentation time.[3] The successful use of microbial glycolipids and hydroxy-oleic acid (HOA) derived therefrom as bio-based intermediates requires reliable analytical methods as well as robust manufacturing processes for the synthesis and cleavage of bio-based molecules. In order to obtain hydroxy-oleic acids as bio-based intermediates, the acidic cleavage of microbial derived sophorolipid was investigated. In addition the implementation of HOA in polyurethane (PU) systems was explored.
Aerobic microbial cultivations are industrially important group of processes and pose challenges for the reactor design. In particular, estimation of industrial scale conditions is difficult from laboratory and pilot scale data. Due to complex interaction of gas/liquid phase hydrodynamics, mass transfer parameters and microbial metabolism, both improvement of modelling tools and reactor design are desired. We present an approach to estimate growth conditions in industrial scale reactor by combining black-box metabolic models with CFD-model.
The reactor type used here is Outotec OKTOP9000®, which is used in the industrial hydrometallurgical processes at 900 m3 scale. It is adopted to a laboratory setting and compared to stirred tank reactor (STR) in gas dispersion, mass transfer and yeast cultivation experiments. In addition, a kinetic model for the yeast growth is developed based on literature sources and validated by the laboratory scale batch cultivations. This kinetic model is used along with CFD-model that is developed to describe the flow and mass transfer conditions in the industrial scale reactor.
The laboratory scale experiments show the feasibility of OKTOP9000® reactor when compared to STR, particularly with improved gas handling capacity. The modelling approach shows qualitatively similar behavior in the large scale simulations when compared to laboratory scale cultivations.