High Concentrations Of Acetic Acid Research Articles

Enhancing probiotic impact: engineering Saccharomyces boulardii for optimal acetic acid production and gastric passage tolerance.

Saccharomyces boulardii has been a subject of growing interest due to its potential as a probiotic microorganism with applications in gastrointestinal health, but the molecular cause for its probiotic potency has remained elusive. The recent discovery that S. boulardii contains unique mutations causing high acetic acid accumulation and inhibition of bacterial growth provides a possible clue. The natural S. boulardii isolates Sb.P and Sb.A are homozygous for the recessive mutation whi2S270* and accumulate unusually high amounts of acetic acid, which strongly inhibit bacterial growth. However, the homozygous whi2S270* mutation also leads to acetic acid sensitivity and acid sensitivity in general. In the present study, we have constructed a new S. boulardii strain, derived from the widely therapeutically used CMCN I-745 strain (isolated from the pharmaceutical product Enterol), producing even higher levels of acetic acid while keeping the same tolerance toward low pH as the parent Enterol (ENT) strain. This newly engineered strain, named ENT3, has a homozygous deletion of ACH1 and strong overexpression of ALD4. It is also able to accumulate much higher acetic acid concentrations when growing on low glucose levels, in contrast to the ENT wild-type and Sb.P strains. Moreover, we show the antimicrobial capacity of ENT3 against gut pathogens in vitro and observed that higher acetic acid production might correlate with better persistence in the gut in healthy mice. These findings underscore the possible role of the unique acetic acid production and its potential for improvement of the probiotic action of S. boulardii.IMPORTANCESuperior variants of the probiotic yeast Saccharomyces boulardii produce high levels of acetic acid, which inhibit the growth of bacterial pathogens. However, these strains also show increased acid sensitivity, which can compromise the viability of the cells during their passage through the stomach. In this work, we have developed by genetic engineering a variant of Saccharomyces boulardii that produces even higher levels of acetic acid and does not show enhanced acid sensitivity. We also show that the S. boulardii yeasts with higher acetic acid production persist longer in the gut, in agreement with a previous work indicating competition between probiotic yeast and bacteria for residence in the gut.

The effect of chemically modified wood particles on the termite durability of sandwich particleboard from Cotylelobium melanoxylon and Gigantochloa pruriens

The tropical region of Indonesia is a preferred habitat for termites. High humidity is very supportive of the growth of these organisms. The impact resulting from these conditions is the vulnerability to the durability of products made from lignocellulosic because this material is the main feed source for termites. Chemical modification treatment is needed in the manufacturing process to increase product durability. This study aims to analyze the resistance of sandwich particleboard to attack by subterranean termites due to chemical modification of the particles. The sample used in this study was chemically modified particleboard made of raru wood (Cotylelobium melanoxylon) particles and belangke bamboo (Gigantochloa pruriens) strand. Then the samples were fed to subterranean termites (Coptotermes curvignathus) regarding SNI 01.7202-2006. Parameters observed included the percentage of termite weight loss and mortality. The results showed that sandwich particleboard, which was dominated by 80% bamboo and 20% raru wood with acid and alkaline treatment, was not resistant to subterranean termite attack. The weight loss value produced in this study ranged from 11.97 - 15.83%, included in the durable class IV classification. The higher concentration of acetic acid in particle immersion resulted in a decrease in the value of the board’s weight loss, and the opposite condition was experienced by panels with particle immersion treatment using sodium hydroxide (NaOH).

Date Vinegar: First Isolation of Acetobacter and Formulation of a Starter Culture.

There is a lack of scientific analysis and control over the production of date vinegar in Oman, despite its growing demand in the worldwide market. Traditional production of date vinegar may lead to elevated amounts of ethanol (≥0.5%) and reduced content of acetic acid (<4%) compared to the standard acceptable levels. This study aimed to isolate non-Gluconobacter species from date vinegar produced by spontaneous fermentation and formulate starter cultures for quick and efficient production of date vinegar. In spontaneous fermentation date vinegar samples, the highest concentration of acetic acid was 10.42% on day 50. Acetobacter malorum (5 isolates), A. persici (3 isolates), and A. tropicalis (3 isolates) were identified based on 16S rRNA gene sequences for the first time in date vinegar. For date vinegar prepared with a starter culture of Acetobacter and yeast, the highest concentration of acetic acid was 4.67%. In conclusion, spontaneous fermentation resulted in the production of date vinegar with a high concentration of acetic acid, acceptable concentrations of ethanol and methanol, and the first isolation of three Acetobacter species. The formulated starter culture produced acceptable amounts of acetic acid and the time of fermentation was reduced 10 times (from 40 days to 4 days). This can provide the basis for producing a personalized or commercial product that ensures the production of good-quality date vinegar in an easier, faster, safer, and more efficient way from low-quality and surplus dates.

Salt Water Exposure Exacerbates the Negative Response of Phragmites australis Haplotypes to Sea-Level Rise.

The response of coastal wetlands to sea-level rise (SLR) largely depends on the tolerance of individual plant species to inundation stress and, in brackish and freshwater wetlands, exposure to higher salinities. Phragmites australis is a cosmopolitan wetland reed that grows in saline to freshwater marshes. P. australis has many genetically distinct haplotypes, some of which are invasive and the focus of considerable research and management. However, the relative response of P. australis haplotypes to SLR is not well known, despite the importance of predicting future distribution changes and understanding its role in marsh response and resilience to SLR. Here, we use a marsh organ experiment to test how factors associated with sea level rise-inundation and seawater exposure-affect the porewater chemistry and growth response of three P. australis haplotypes along the northern Gulf of Mexico coast. We planted three P. australis lineages (Delta, European, and Gulf) into marsh organs at five different elevations in channels at two locations, representing a low (Mississippi River Birdsfoot delta; 0-13 ppt) and high exposure to salinity (Mermentau basin; 6-18 ppt) for two growing seasons. Haplotypes responded differently to flooding and site conditions; the Delta haplotype was more resilient to high salinity, while the Gulf type was less susceptible to flood stress in the freshwater site. Survivorship across haplotypes after two growing seasons was 42% lower at the brackish site than at the freshwater site, associated with high salinity and sulfide concentrations. Flooding greater than 19% of the time led to lower survival across both sites linked to high concentrations of acetic acid in the porewater. Increased flood duration was negatively correlated with live aboveground biomass in the high-salinity site (χ2 = 10.37, p = 0.001), while no such relationship was detected in the low-salinity site, indicating that flood tolerance is greater under freshwater conditions. These results show that the vulnerability of all haplotypes of P. australis to rising sea levels depends on exposure to saline water and that a combination of flooding and salinity may help control invasive haplotypes.

The Potential of Katmon Fruit (Dellenia philippinensis) Extract as a Natural Food Preservative

This study investigates the potential of Katmon fruit (Dellenia philippinensis) extract as a natural food preservative. The methodology encompassed the extraction of key components from the fruit and their subsequent Analysis. Computational evaluations, based on data from Tables 1, 2, and 3, reveal a significant correlation between the acetic acid concentration in the extract and its antimicrobial effectiveness. Results demonstrate the extract's substantial capability to inhibit microbial growth, which is attributed to its high antioxidant and acetic acid content. Sensory evaluations suggest the extract does not compromise food quality. The discussion underscores the advantages of Katmon fruit extract over synthetic preservatives, highlighting its natural, cost-effective, and eco-friendly nature. The study adds to the understanding of natural food preservation, proposing a viable alternative to synthetic additives, with implications supported by computational data analyses.

New biomarkers underlying acetic acid tolerance in the probiotic yeast Saccharomyces cerevisiae var. boulardii

Evolutionary engineering experiments, in combination with omics technologies, revealed genetic markers underpinning the molecular mechanisms behind acetic acid stress tolerance in the probiotic yeast Saccharomyces cerevisiae var. boulardii. Here, compared to the ancestral Ent strain, evolved yeast strains could quickly adapt to high acetic acid levels (7 g/L) and displayed a shorter lag phase of growth. Bioinformatic-aided whole-genome sequencing identified genetic changes associated with enhanced strain robustness to acetic acid: a duplicated sequence in the essential endocytotic PAN1 gene, mutations in a cell wall mannoprotein (dan4Thr192del), a lipid and fatty acid transcription factor (oaf1Ser57Pro) and a thiamine biosynthetic enzyme (thi13Thr332Ala). Induction of PAN1 and its associated endocytic complex SLA1 and END3 genes was observed following acetic acid treatment in the evolved-resistant strain when compared to the ancestral strain. Genome-wide transcriptomic analysis of the evolved Ent acid-resistant strain (Ent ev16) also revealed a dramatic rewiring of gene expression among genes associated with cellular transport, metabolism, oxidative stress response, biosynthesis/organization of the cell wall, and cell membrane. Some evolved strains also displayed better growth at high acetic acid concentrations and exhibited adaptive metabolic profiles with altered levels of secreted ethanol (4.0–6.4% decrease), glycerol (31.4–78.5% increase), and acetic acid (53.0–60.3% increase) when compared to the ancestral strain. Overall, duplication/mutations and transcriptional alterations are key mechanisms driving improved acetic acid tolerance in probiotic strains. We successfully used adaptive evolutionary engineering to rapidly and effectively elucidate the molecular mechanisms behind important industrial traits to obtain robust probiotic yeast strains for myriad biotechnological applications.Key points•Acetic acid adaptation of evolutionary engineered robust probiotic yeast S. boulardii•Enterol ev16 with altered genetic and transcriptomic profiles survives in up to 7 g/L acetic acid•Improved acetic acid tolerance of S. boulardii ev16 with mutated PAN1, DAN4, OAF1, and THI13 genesGraphical

Sources of elevated organic acids in the mountainous background atmosphere of southern China

Formic acid (FA) and acetic acid (AA) are pivotal organic acids in the troposphere, significantly influencing atmospheric chemistry. However, their abundance and sources in the mountainous background atmosphere remain underexplored. We undertook continuous measurements of FA and AA in Nanling mountains, southern China, during autumn 2020 using a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS). Both acids registered higher concentrations than in other global high-altitude or forested locations, averaging at 0.89 (max: 3.91) and 0.95 (max: 3.52) ppbv for FA and AA, respectively. High concentrations of FA and AA in this forested background area arose from secondary formation and biomass burning, collectively contributing 71 % to 89 %. During episodes, FA and AA concentrations surged 2–3 times, owing to the enhanced atmospheric oxidation capacity. The secondary FA production was predominantly due to isoprene oxidation among the VOC precursors studied. However, observed inconsistencies between calculated and actual FA concentrations suggest overlooked precursors or mechanisms warranting further investigation. Our findings can enhance the understanding of organic acid characteristics and the interplay of biogenic and anthropogenic sources in the background atmosphere.

Exploring the Potential of Wood Vinegar: Chemical Composition and Biological Effects on Crops and Pests

Wood vinegar is a by-product of the pyrolysis of organic raw materials. In this study, we investigated the chemical composition and biological activity of industrial wood vinegar derived from the pyrolysis of wood pruning waste. The composition of wood vinegar was characterized using liquid chromatography (LC) and gas chromatography–mass spectrometry (GC-MS). Wood vinegar bioactivity was tested against Bactrocera oleae under field conditions in an olive grove for two years. Furthermore, wood vinegar was applied in a greenhouse experiment with strawberry plants and in a strawberry field infested with the nematode Meloidogyne incognita. Finally, a seed root length bioassay was performed to evaluate the phytotoxicity or biostimulation of wood vinegar on Eruca sativa, Lactuca sativa, Lens culinaryis, Lolium multiflorum, and Solanum lycopersicum. Our results showed that wood vinegar had a pH of 3.2, with high concentrations of acetic acid (27,840.16 mg L−1) and phenols (54.00 mg L−1). No repellent effect against B. oleae was observed when wood vinegar was applied as an aerosol in olive groves. On strawberry plants in greenhouse conditions, wood vinegar showed phytotoxic effects at high concentrations, resulting in a decrease in the total yield of the plants. In the field, at a 1% concentration, wood vinegar led to a significant 15% reduction in the infection caused by M. incognita in strawberry plants. Finally, in the in vitro crop bioassay, wood vinegar demonstrated remarkable phytotoxicity effects at high concentrations while promoting root growth when diluted. The efficacy of wood vinegar displayed considerable variability based on concentration and delivery system, emphasizing the need for careful evaluation when considering its application, particularly in diverse crops and production systems.

Effects of different marination conditions on the physico-chemical and microbiological quality of anchovy (Engraulis encrasicolus) fillets inoculated with Morganella psychrotolerans during cold storage.

This study is aimed to determine the effects of different marination conditions (1, 2, 3, 4% acetic and 6, 8, 10% NaCl) on the anchovy fillets inoculated with Morganella psychrotolerans during refrigerated storage (4±1°C) for three months. According to the results of study, marination has great inhibitory effects on the growth of M. psychrotolerans. Total psychrophilic bacteria, total lactic acid bacteria, total yeast and mold, Total Enterobacteriaceae and M. psychrotolerans growth were not observed in the groups treated with 3 and 4% acetic acid. Control groups and fillets marinated with 1% acetic acid showed lower sensory scores. Those groups were rejected on 30th, 45th and 60th days of the storage, respectively, while the groups marinated with 2%, 3%, and 4% acetic acid had higher sensory scores and they were still acceptable until at the end of the study. According to peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) assessment, lipid oxidation was delayed in the fillets marinated with high acetic acid concentrations (3 and 4%) comparing with the control and other inoculated fillets. From this research it can be revealed that high acetic acid and salt concentrations suppress the bacteria growth in the anchovy fillets. Thus, marination process can be recommended to be used as a preservation method to inhibit bacterial growth in anchovy fillets for a safe consumption.

High acetate titer obtained from CO2 by thermophilic microbial electrosynthesis with Thermoanaerobacter kivui

Novel renewable platforms for production of organic molecules need to be developed and deployed to achieve a circular carbon economy. Microbial electrosynthesis (MES) is a promising technology to produce acetate from CO2 and renewable electricity. However, productivity and product titer improvements are needed for electroacetogenesis to compete with other production methods. Here, we report the production of high concentrations of acetic acid by Thermoanaerobacter kivui in a continuous, H2-mediated, and thermophilic microbial electrosynthesis process. Acetate titers correlated inversely with the production rate: 490 mM (29.4 g L−1) acetate were produced at a production rate of 5.66 mM h−1 (0.34 g L−1 h−1) whereas 390 mM (23.4 g L−1) acetate were produced at a production rate of 12.75 mM h−1 (0.76 g L−1 h−1). This indicates that electrosynthesis rates are limited by product inhibition rather than electron donor supply at high acetate concentrations.

Investigation of Acid Tolerance Mechanism of Acetobacter pasteurianus under Different Concentrations of Substrate Acetic Acid Based on 4D Label-Free Proteomic Analysis.

Acetobacter pasteurianus is always used to brew vinegar because of its ability of producing and tolerating a high concentration of acetic acid. During vinegar fermentation, initial acetic acid contributes to acetic acid accumulation, which varies with initial concentrations. In this study, to investigate the mechanisms of tolerating and producing acetic acid of Acetobacter pasteurianus under different concentrations of substrate acetic acid, four-dimensional label-free proteomic technology has been used to analyze the protein profiles of Acetobacter pasteurianus at different growth stages (the lag and exponential phases) and different substrate acetic acid concentrations (0%, 3%, and 6%). A total of 2093 proteins were quantified in this study. The differentially expressed proteins were majorly involved in gene ontology terms of metabolic processes, cellular metabolic processes, and substance binding. Under acetic acid stress, strains might attenuate the toxicity of acetic acid by intensifying fatty acid metabolism, weakening the tricarboxylic acid cycle, glycerophospholipid and energy metabolism during the lag phase, while strains might promote the assimilation of acetic acid and inter-conversion of substances during the exponential phase by enhancing the tricarboxylic acid cycle, glycolysis, pyruvate, and energy metabolism to produce and tolerate acid. Besides, cell cycle regulation and protein translation might be potential acid tolerance pathways under high acid stress. The result contributes to the exploration of new potential acid tolerance mechanisms in Acetobacter pasteurianus from four-dimensional label-free relative quantitative proteomics analysis.

Effects of MgCl2 on sludge anaerobic digestion: Hydrolysis, acidogenesis, methanogenesis, and microbial characteristics

Back diffused draw salt affects the anaerobic digestion performance in a forward osmosis membrane bioreactor. Previous studies have established the influence of MgCl2 on sludge anaerobic digestion; however, its effects on individual phases, such as hydrolysis, acidogenesis, and methanogenesis remain unclear. This study investigates the influence of different concentrations of MgCl2 on these stages of anaerobic digestion and compares variations in methane production under different substrates. The findings demonstrate that adding MgCl2 significantly enhances sludge hydrolysis. At a concentration of 50 g/L, the soluble chemical oxygen demand increases by 265.2 %, although with unstable reactions. MgCl2 significantly affects the production of fatty acids. Specifically, the production of acids was enhanced when the concentration of MgCl2 was below 20 g/L, while it was inhibited when the concentration exceeded 50 g/L. The highest concentration of acetic acid recorded is 1991.28 mg/L, which represents an 83.5 % increment. In contrast, methane production shows a higher susceptibility to MgCl2, experiencing inhibition at concentrations exceeding 1 g/L. The inhibitory concentration for methane production is lower than for acid production. The study also observes significant differences in microbial structure, particularly in Methanogen. When using different substrates, the predominant orders of methanogen are Methanobacteriales for tests with acid solution as a feed and Methanosarcinales for tests with waste sludge as a feed, respectively. Analyses of metabolic pathways reveal that carbon dioxide and acetic acid are the most prevalent pathways in terms of abundance. In summary, MgCl2 has varying effects on various stages of anaerobic digestion of sludge.

Adaptive laboratory evolution of Salmonella enterica in acid stress.

Adaptive laboratory evolution (ALE) studies play a crucial role in understanding the adaptation and evolution of different bacterial species. In this study, we have investigated the adaptation and evolution of Salmonella enterica serovar Enteritidis to acetic acid using ALE. Acetic acid concentrations below the minimum inhibitory concentration (sub-MIC) were used. Four evolutionary lineages (EL), namely, EL1, EL2, EL3, and EL4, of S. Enteritidis were developed, each demonstrating varying levels of resistance to acetic acid. The acetic acid MIC of EL1 remained constant at 27 mM throughout 70 days, while the MIC of EL2, EL3, and EL4 increased throughout the 70 days. EL4 was adapted to the highest concentration of acetic acid (30 mM) and demonstrated the highest increase in its MIC against acetic acid throughout the study, reaching an MIC of 35 mM on day 70. The growth rates of the evolved lineages increased over time and were dependent on the concentration of acetic acid used during the evolutionary process. EL4 had the greatest increase in growth rate, reaching 0.33 (h-1) after 70 days in the presence of 30 mM acetic acid as compared to EL1, which had a growth rate of 0.2 (h-1) after 70 days with no exposure to acetic acid. Long-term exposure to acetic acid led to an increased MIC of human antibiotics such as ciprofloxacin and meropenem against the S. enterica evolutionary lineages. The MIC of ciprofloxacin for EL1 stayed constant at 0.016 throughout the 70 days while that of EL4 increased to 0.047. Bacterial whole genome sequencing revealed single-nucleotide polymorphisms in the ELs in various genes known to be involved in S. enterica virulence, pathogenesis, and stress response including phoP, phoQ, and fhuA. We also observed genome deletions in some of the ELs as compared to the wild-type S. Enteritidis which may have contributed to the bacterial acid adaptation. This study highlights the potential for bacterial adaptation and evolution under environmental stress and underscores the importance of understanding the development of cross resistance to antibiotics in S. enterica populations. This study serves to enhance our understanding of the pathogenicity and survival strategies of S. enterica under acetic acid stress.

Implication of amino acid metabolism and cell surface integrity for the thermotolerance mechanism in the thermally adapted acetic acid bacterium Acetobacter pasteurianus TH-3.

Acetobacter pasteurianus, an industrial vinegar-producing strain, is suffered by fermentation stress such as fermentation heat and/or high concentrations of acetic acid. By an experimental evolution approach, we have obtained a stress-tolerant strain, exhibiting significantly increased growth and acetic acid fermentation ability at higher temperatures. In this study, we report that only the three gene mutations of ones accumulated during the adaptation process, ansP, dctD, and glnD, were sufficient to reproduce the increased thermotolerance of A. pasteurianus. These mutations resulted in cell envelope modification, including increased phospholipid and lipopolysaccharide synthesis, increased respiratory activity, and cell size reduction. The phenotypic changes may cooperatively work to make the adapted cell thermotolerant by enhancing cell surface integrity, nutrient or oxygen availability, and energy generation.

Microwave-assisted unfermented cocoa bean: improving flavor precursor after acetic acid submersion.

Objective was to enhance flavor precursors of unfermented cocoa beans by soaking beans in acetic acid and further heated by microwave. Acetic acid concentration, microwave power, and microwave exposure time were investigated and screened using a one-variable-at-a-time approach. Optimum condition for degree of hydrolysis (DH) was determined by Response Surface Methodology using Box-Behnken Design. Results showed that flavor precursors increased at a higher acetic acid concentration, microwave power, and microwave exposure time. Optimum condition was achieved at acetic acid concentration of 1.21M, microwave power at 450 W, and microwave exposure time of 4min. The microwave-assisted cocoa bean had a DH of 38.99% and a reducing sugar of 0.98%. Microwave-assisted heating increased amino acid content, especially hydrophobic amino acids as flavor precursors, and the main volatile compounds, especially aldehyde and pyrazine. Thus, microwave-assisted heating is a promising alternative to improve flavor precursors of unfermented cocoa beans.

Sequential bioconversion of C1-gases (CO, CO2, syngas) into lipids, through the carboxylic acid platform, with Clostridium aceticum and Rhodosporidium toruloides

Syngas (CO, CO2, H2) was effectively bioconverted into lipids in a two-stage process. In the first stage, C1-gases were bioconverted into acetic acid by the acetogenic species Clostridium aceticum through the Wood-Ljungdahl metabolic pathway in a stirred tank bioreactor, reaching a maximum acetic acid concentration of 11.5 g/L, with a production rate of 0.05 g/L·h. Throughout this experiment, samples were extracted at different periods, i.e., different concentrations, to be used in the second stage, aiming at the production of lipids from acetic acid. The yeast Rhodosporidium toruloides, inoculated in the acetogenic medium, was able to efficiently accumulate lipids from acetic acid generated in the first stage. The best results, in terms of lipid content, dry biomass, biomass yield (Y(X/S)) and lipid yield (Y(L/S)) were 39.5% g/g dry cell weight, 3 g/L, 0.35 and 0.107, respectively. In terms of abundance, the lipid profile followed the order: C18:1 > C16:0 > C18:2 > C18:0 > Others. Experiments were also performed to determine the toxicity exerted by high concentrations of acetic acid on R. toruloides, resulting in inhibition at initial acid concentrations around 18 g/L leading to a higher lag phase and being lethal to the yeast at initial acetic acid concentrations around 22 g/L and above. This research paves the way for a novel method of growing oleaginous yeasts to produce sustainable biofuels from syngas or C1-pollutant gases.

Fermented milk by Lactobacillus delbrueckii, Lacticaseibacillus paracasei, and Kluyveromyces marxianus shows special physicochemical and aroma formation during the storage

In this study, the microbial interactions among co-culture of Lactobacillus delbrueckii DPUL-F36, Lacticaseibacillus paracasei DPUL-F115, and Kluyveromyces marxianus 39 in fermented milk were evaluated during 13 days of refrigerated storage (4 ± 0.5 °C), in terms of titratable acidity, viable cell counts and metabolites. The fermented milk involving K.marxianus 39 showed a maximum lactobacilli count (4.8 × 109 CFU/mL) and titratable acidity (151.0 ± 1.7 °T). K. marxianus 39 could enrich the flavor of the fermented milk and improve the sensory quality of the fermented milk on the 5th and 9th day of storage. The contents of aspartic acid, glycine, alanine, valine, methionine, leucine, lysine, and tyrosine increased significantly, while the contents of valine, methionine, leucine, phenylalanine, and lysine in milk fermented by Lactobacillus delbrueckii DPUL-F36, Lacticaseibacillus paracasei DPUL-F115, and Kluyveromyces marxianus 39 were significantly lower than those in milk fermented by Lactobacillus delbrueckii DPUL-F36, Lacticaseibacillus paracasei DPUL-F115 during storage. The higher concentrations of acetic acid, nonanoic acid, acetoin, 2-nonanone, and 2-undecanol were observed in the fermented milk involved with K. marxianus 39. Our results showed K. marxianus 39 has the potential to be a starter culture for fermented dairy products.

On the Rich Chemistry of Pseudo-Protic Ionic Liquid Electrolytes.

Mixing weak acids and bases can produce highly complicated binary mixtures, called pseudo-protic ionic liquids, in which a complex network of effects determines the physicochemical properties that are currently impossible to predict. In this joint computational-experimental study, we investigated 1-methylimidazole-acetic acid mixtures through the whole concentration range. Effects of the varying ionization and excess of either components on the properties, such as density, diffusion coefficients, and overall hydrogen bonding structure were uncovered. A special emphasis was put on understanding the multiple factors that govern the conductivity of the system. In the presence of an excess of acetic acid, the 1-methylimidazolium acetate ion pairs dissociate more efficiently, resulting in a higher concentration of independently moving, conducting ions. However, the conductivity measurements showed that higher concentrations of acetic acid improve the conductivity beyond this effect, suggesting in addition to standard dilution effects the occurrence of Grotthuss diffusion in high acid-to-base ratios. The results here will potentially help designing novel electrolytes and proton conducting systems, which can be exploited in a variety of applications.

Characterization of Melon, (Cucumis melo L.) Silage with Different Biomass Mixtures and Dry Matter Contents

The objective of this study was to obtain different dry matter contents and proportions of melon plant biomass for silage making. A completely randomized design with factorial arrangement (3 × 2) and four replications was adopted. The first factor consisted of three melon biomass mixtures based on as-fed composition of plant (branches + leaves) and harvested melon (fruits)—100% plant (0% fruit), 90% plant + 10% fruit, and 100% fruit. The second factor corresponded to the ensiled material, which was either fresh or dehydrated in the field after harvest (40% dry matter). Silages produced from dehydrated biomass after fruit harvest, containing 0% and 10% fruit, showed the highest dry matter contents: 297 g/kg and 293 g/kg, respectively. Silages produced from fresh biomass containing 0% and 10% fruit showed high concentrations of acetic acid, reaching 14.9 g/kg and 14.1 g/kg, respectively. Silages produced from dehydrated biomass containing 10% and 100% fruit showed better results in terms of the indicators associated with high-quality silage. Dehydration improves the fermentative profile and overall quality of melon silage.

Untargeted Metabolomics Analysis Revealed the Difference of Component and Geographical Indication Markers of Panax notoginseng in Different Production Areas.

Panax notoginseng (P. notoginseng) has excellent medicinal and food dual-use characteristics. However, P. notoginseng with a unique origin label has become the target of fraud because of people confusing or hiding its origin. In this study, an untargeted nuclear magnetic resonance (NMR)-based metabolomics approach was used to discriminate the geographical origins of P. notoginseng from four major producing areas in China. Fifty-two components, including various saccharides, amino acids, saponins, organic acids, and alcohols, were identified and quantified through the NMR spectrum, and the area-specific geographical identification components were further screened. P. notoginseng from Yunnan had strong hypoglycemic and cardiovascular protective effects due to its high acetic acid, dopamine, and serine content, while P. notoginseng from Sichuan was more beneficial for diseases of the nervous system because of its high content of fumarate. P. notoginseng from Guizhou and Tibet had high contents of malic acid, notoginsenoside R1, and amino acids. Our results can help to distinguish the geographical origin of P. notoginseng and are readily available for nutritional recommendations in human consumption.