Optimisation of Propane Production from Hydrothermal Decarboxylation of Butyric Acid Using Pt/C Catalyst: Influence of Gaseous Reaction Atmospheres

The displacement and eventual replacement of fossil-derived fuel gases with biomass-derived alternatives can help the energy sector to achieve net zero by 2050. Decarboxylation of butyric acid, which can be obtained from biomass, can produce high yields of propane, a component of liquefied petroleum gases. The use of different gaseous reaction atmospheres of nitrogen, hydrogen, and compressed air during the catalytic hydrothermal conversion of butyric acid to propane have been investigated in a batch reactor within a temperature range of 200–350 °C. The experimental results were statistically evaluated to find the optimum conditions to produce propane via decarboxylation while minimizing other potential side reactions. The results revealed that nitrogen gas was the most appropriate atmosphere to control propane production under the test conditions between 250 °C and 300 °C, during which the highest hydrocarbon selectivity for propane of up to 97% was achieved. Below this temperature range, butyric acid conversion remained low under the three reaction atmospheres. Above 300 °C, competing reactions became more significant. Under compressed air atmosphere, oxidation to CO2 became dominant, and under nitrogen, thermal cracking of propane became significant, producing both ethane and methane as side products. Interestingly, under a hydrogen atmosphere, hydrogenolytic cracking propane became dominant, leading to multiple C–C bond cleavages to produce methane as the main side product at 350 °C.

Vpliv sezone na in vitro razgradljivost in fermentabilnost krmil v vampovem soku navadnega jelena (Cervus elaphus L.)

Transition from summer to winter changes red deer digestive tract physiology and digestive processes. The objective of the trial was to determine the effects of season on in vitro apparent (<em>iv</em>ADMD) and true dry matter (<em>iv</em>TDMD) digestibility, in vitro gas production parameters and short-chain fatty acid synthesis (SCFA) in red deer hinds of eleven substrates naturally occurring in Slovenia (chestnut fruits, acorns of common and sessile oak, two fresh grasses) and those frequently used in supplemental red deer feeding (two grass hays and two grass silages, apple pomace and sugar beet roots). There were no differences in <em>iv</em>ADMD, <em>iv</em>TDMD, determined by incubation of feeds in buffered rumen fluid, as there were no differences in majority of gas production parameters between autumn and winter season. Only the parameter “C” (specific gas production rate) was frequently higher (<em>p</em> &lt; 0.05) in winter season than in autumn season. The amounts of SCFA were similar between two seasons. However, the proportion of acetic acid tended to be higher in winter, while the proportions of propionic and butyric acid tended to be higher in autumn than in winter especially in high fibre feeds. On contrary, in high starch feeds such as oak acorns and chestnut fruits, the proportion of propionic acid was higher (<em>p</em> &lt; 0.05) in winter, while of butyric acid in autumn (<em>p</em> &lt; 0.05). Despite the fact that the number of used substrates (n = 11) and animal rumen fluid donors (n = 6) were small, these results indicate a shift in rumen microbial metabolism between autumn and winter season.

Clinical and metabolic effects of metaprebiotic therapy for some functional bowel diseases

Aim of investigation: to assess the effectiveness and tolerance of dietary supplements (BAA) STIM and STIM LaxMaterials and methods: The analysis of the treatment of 73 patients who were divided into 2 groups. Group 1-32 patients with functional constipation (8 men and 24 women; mean age — 45.7 ± 12.4 years), Group 2-41 patients with functional diarrhea (19 men and 22 women; mean age — 41.0 ± 15,8 years). The study of clinical symptoms was carried out according to the data of an individual diary, using specialized questionnaires with a scoring of symptoms before and after the course of treatment, before and after treatment, the result of the carbolene test, the content of short-chain fatty acids in the feces was assessed. Tolerability was assessed by recording side effects and adverse events.Monotherapy was carried out with STIM LAX for patients with functional constipation at a dose of 1 tablet 3 times a day for 30 days. STIM for patients with functional diarrhea was prescribed in a dose of 2 tablets 3 times a day for 30 days.Results of the study: The results of the study showed that FC therapy with StimLax effectively reduces the frequency and intensity of symptoms such as difficulty / pain, discomfort during defecation, feeling of incomplete emptying, abdominal pain, time spent in the toilet and the number of failed bowel movements. We observed the normalization of transit time according to the carbolene test and an increase in stool frequency up to 5 times a week.Treatment of patients with FD with Stim led to a significant decrease in the intensity of abdominal pain, rumbling, flatulence, stool frequency, an increase in the time of the carbolene test and the normalization of its consistency.Adverse events were observed in 8 (10.9%) patients (4 patients with FD and 4 patients with FD). On the 3-5th day of treatment, there was an increase in flatulence, rumbling in the abdomen. A temporary decrease in the dose of the drug to 1-2 tablets per day removed these phenomena and the symptoms that appeared were resolved within 1-3 days. After that, the dose of the drug was gradually increased to the initial (effective), which the patients tolerated normally.Conclusions: The results of this study indicate high clinical efficacy and good tolerability of treatment with drugs StimLax and Stim in patients with FC and FD. In some cases, it is necessary to titrate the dose of the drug (downward), but this is not accompanied by a decrease in the effectiveness of therapy. The use of these drugs with metaprebiotic properties helps to modify the microbiota of patients with functional bowel diseases. With constipation, the number and activity of both lactic acid flora and microorganisms that produce butyric acid are stimulated; in addition, calcium lactate is an additional source of butyric acid due to metabolism. With diarrhea, along with the stimulation of the number and activity of the lactic acid flora, there is an improvement in the utilization of butyrate by intestinal cells.

MOLECULAR-DYNAMIC SIMULATION OF MIXTURES OF MODIFIED FULLERENES AND 1,8-OCTANDITHIOL

В данной работе мы сообщаем о результатах сравнительного атомистического моделирования двух систем, содержащих функцианализированные фуллерены метилового эфира фенил- C-масляной кислоты (PCBM ) и фенил- C-масляной кислоты (PCBM ) в присутствии растворителя 1,8-октандитиола (ODT). Для реализации расчетов использовался метод молекулярной динамики на базе программного пакета LAMMPS. Зафиксировано принципиальное различие в упаковке молекул PCBM и PCBM . В случае систем с PCBM наблюдается тенденция к постепенному разделению растворителя и фуллеренов. При этом в образцах с PCBM наблюдается тенденция к формированию устойчивых трехмерных сетчатых структур, образованных двумя взаимопроникающими фазами: фуллеренами и молекулами ODT. С целью проверки масштабируемости наблюдаемого структурного упорядочения для смеси PCBM с ODT было выполнено моделирование в ячейке с удвоенным размером ребер. В этом случае мы также наблюдаем формирование биконтинуальных структур из фуллеренов и растворителя. In this work, we report on the results of comparative atomistic modeling of two systems containing functionalized fullerenes of phenyl-C-butyric acid methyl ester (PCBM ) and phenyl- C -butyric acid (PCBM ) in the presence of a high-boiling solvent 1,8 -octanedithiol (ODT). The calculations were performed by full atomistic molecular dynamics with using LAMMPS software package. A fundamental difference in the packaging of PCBM and PCBM molecules was detected. In the case of systems with PCBM , there is a tendency towards gradual separation of the solvent and fullerenes. At the same time, in samples with PCBM , there is a tendency to the formation of stable three-dimensional network structures formed by two interpenetrating phases: fullerenes and ODT molecules. In order to check the scalability of the observed structural ordering for the mixture of PCBM with ODT, an additional simulation was performed in a cell with doubled edge size. In this case, we also observe the formation of bicontinual structures from fullerenes and the solvent.

Enrichment of Homoacetogens Converting H2/CO2 into Acids and Ethanol and Simultaneous Methane Production

An anaerobic granular sludge was enriched to utilize H2/CO2 in a continuous gas-fed up-flow anaerobic sludge reactor by applying operating conditions expected to produce acetic acid, butyric acid and ethanol. Three stages of fermentation were found: Stage I with acetic acid accumulation with the highest concentration of 35 mM along with a pH decrease from initial 6 to 4.5. In Stage II, H2/CO2 was replaced by 100% H2 to induce solventogenesis, whereas butyric acid was produced with the highest concentration of 2.5 mM. At Stage III with 10 μM tungsten (W) addition, iso-valeric acid, valeric acid and caproic acid were produced at pH 4.5 -5.0. In the batch tests inoculated with the enriched sludge taken from the bioreactor (day 70), however, methane production occurred at pH 6. Exogenous 15 mM acetate addition enhanced both the H2 and CO2 consumption rate compared to exogenous 10, 30 and 45 mM acetate by the enriched sludge. Exogenous acetate failed to be converted to ethanol using H2 as electron donor by the enriched acetogens.