Types Of Organic Acids Research Articles

Enhancing the potential application of food-waste biochar as a sustainable bio-solid fuel: Analysis of post-treatment and combustion behavior

Food-waste biochar holds significant potential as a bio-solid fuel for achieving carbon neutrality; however, its high content of sodium (Na), potassium (K), calcium (Ca), chlorine (Cl), and nitrogen, inhibits its potential use. This study explored the effects of post-treatment with ascorbic, acetic, citric, and iminodiacetic acids on the properties of food-waste biochar and volatile ionic substances to establish a foundation for assessing both the environmental impact and practical use of food waste. Post-treatment with organic acids achieved 92% Cl-removal efficiency and induced deformation of the functional groups of food-waste biochar surfaces, leading to the re-adsorption of alkali and alkaline earth metals. This re-adsorption of alkali metal ions showed a distinct correlation with NOx mitigation. The amount of re-adsorbed Na and K varied based on the types of organic acids, resulting in different NOx emission reduction effects. Iminodiacetic acid was particularly effective in alleviating Ca and PO4 volatilization, whereas citric acid exhibited the highest Ca elution performance, and the Ca-contained leachate is a potential source of CO2 storage through indirect mineral carbonation. Acetic acid is the most feasible alternative, considering both economic and environmental aspects. The findings suggest that the post-treatment of food-waste biochar effectively mitigates air pollutants during combustion and is beneficial for sustainable biosolid fuel production and bio-waste management.

Production of Citric Acid from Different Aspergillus species Obtained from Soil

The genus Aspergillus is considered highly important in the production of various types of enzymes and organic acids. Aspergillus species produce organic acids such as citric acid, itaconic acid, and malic acid, which are one of the most important alternate techniques for chemical processes. Citric acid is an essential primary agricultural product that is extensively used in the world. It acts as an intermediate in the tricarboxylic acid cycle (citric acid cycle) during the oxidation of carbohydrates to carbon dioxide. Citric acid has an important role in industries involving the production of food products, beverages, pharmaceutical and agricultural products, detergents, and cosmetics. The production of citric acid, a crucial agricultural commodity with widespread applications in various industries including food, beverages, pharmaceuticals, agriculture, detergents, and cosmetics, heavily relies on microbial fermentation. The great demand for citric acid due to its wide industrial applications and less toxicity. Citric acid can be produced using less expensive substrates that are renewable too. In this work, Aspergillus species was isolated from the soil source, collected in different localities of Chhatrapati Sambhajinagar. The total 90 different isolates are isolated among these the 20 different Aspergillus species are isolated and pure culture by using potato dextrose agar (PDA) Czapek dox agar medium and study the effect of different media on growth and sporulation of different Aspergillus species and the quantitative analysis of citric acid production was done by titration method with help of NaOH and phenolphthalein indicator. The main reason for the study increases is the large number of applications that can be found for citric acid, primarily in the food and pharmaceutical industries

Organic acid type in kimchi is a key factor for determining kimchi starters for kimchi fermentation control

This study was conducted to confirm the effectiveness of kimchi starters (KSs) by investigating their growth characteristics. First, we assessed the growth characteristics of five lactic acid bacteria (LAB) strains (Lactococcus lactis WiKim0124; Companilactobacillus allii WiKim39; and Leuconostoc mesenteroides WiKim0121, WiKim33, and WiKim32) and assessed the effects of different parameters, including organic acids, salinity, acidity, and temperature, on the growth of these LAB. The findings showed that organic acids, particularly acetic and lactic acids that accumulated with the progress in fermentation, were the major players determining the microbial composition of kimchi and the growth of the KSs. Leuconostoc mesenteroides grew well in the presence of acetic and lactic acids than other starts, so it is confirmed that Leuconostoc mesenteroides can dominant in kimchi. In addition, malic acid, which is derived from kimchi ingredients, is used to induce malolactic fermentation by Lactobacillus species, and the progression of malolactic fermentation can be controlled through KSs. Our results suggest that KSs promote the production of organic acids, and the profiling of organic acids, as well as the progress of malolactic fermentation, can be controlled by selecting the suitable KS. Overall, this study demonstrates that kimchi fermentation can be controlled more effectively if the characteristics of KS are understood and used appropriately.

Green solutions for desalinated water drip irrigation systems: Organic acids outperform inorganic acids in fouling control

Desalinated saline water (DSW) has been widely applied in many fields due to global water scarcity. However, fouling formation in desalinated saline water distribution systems (DSWDS) raises serious technical concerns. The conventional approaches (e.g., inorganic acids) for DSWDS fouling control is not only ineffective sometimes but also lead to serious environmental and health risks. Accordingly, this study introduces a greener method utilizing organic acids for antifouling in DSWDS. The performances and influences of three types of inorganic acids (hydrochloric acid (HCl), phosphoric acid (H3PO4) and hydrofluoric acid (HF)) and three types of organic acids (citric acid (C6H8O7), formic acid (CH2O2) and oxalic acid (H2C2O4)) on DSWDS fouling control were investigated and compared. The obtained results indicated that in general, organic acids exhibited higher antifouling capacities than inorganic acids. Among the selected six acids, CH2O2 was the most effective, followed by H2C2O4, H3PO4, C6H8O7, HCl, and HF. In comparison with the most commonly used inorganic HCl, the fouling dry weights in the samples treated with C6H8O7, CH2O2, and H2C2O4 reduced by an average of 8.9 %, 45.3 %, and 33.2 %, respectively. Despite the higher acidity of inorganic acid solutions compared to organic acids, the latter exhibited a stronger chelating capacity for cations (e.g., Ca2+, Mg2+) in DSW, showing a lower tendency to form precipitation in their treated groups. Moreover, organic acids could increase the crystal cell volume and change the chemical bond length of chemical precipitation, resulting in lattice distortions. Furthermore, organic acids can slow down the flocculation and settling of suspended particulate matter, thereby alleviating the formation of particulate fouling. Overall, these findings suggest that the application of organic acids is a more effective and environmental-friendly approach for fouling control compared to inorganic acids, which provides qualitative and quantitative insights into developing greener antifouling protocol for DSW delivery in actual field practices.

Screening of Organic Acid Type and Dosage in Drinking Water for Young Rabbits.

Organic acids (OAs) are employed in animal feed to regulate gastrointestinal disorders and diarrhoea thanks to their ability to modulate the gastrointestinal environment and their antimicrobial capacity. However, there is not enough evidence regarding the most adequate OA and its effectiveness in rabbit farming. Therefore, the aim of this study was to screen and evaluate the response of young rabbits to six OAs, administered via drinking water, at three different concentrations (pH levels). Organic acids (acetic, ACET; formic, FOR; propionic, PROP; lactic, LAC; citric, CIT; and butyric, BUT) were tested at three concentrations (pH 3, 4, and 5). A negative control (CON; non-acidified water) was also included. We used 240 weaned rabbits (28 days old) divided into 2 batches. In each batch, animals were randomly allocated to 1 of the 19 experimental treatments and were housed in group cages of 6 animals per cage, treatment, and batch. Among the 240 rabbits, an additional cage with 6 animals was included to determine the initial physiological state of the animals. All animals were fed with commercial pelleted feed throughout the whole experiment. The duration of the study was 7 days, until 35 days of age. At 31 and 35 days of age, in each batch, three animals per day and treatment were slaughtered. The pH of the digestive contents in the fundus, antrum, duodenum, jejunum, ileum, and cecum, as well as the gastric pepsin enzyme activity, was measured. Water and feed consumption per cage and individual body weight (BW) were recorded daily. The type and dosage of OAs affected water intake. ACET 3, PROP 3, and BUT 3 reduced water intake compared to CON, negatively impacting feed intake and weight gain. FOR and CIT acids led to the highest BW and weight gain at 35 days, compared to PROP, LAC, and BUT (p < 0.05); showing ACET intermediate values. While OAs had limited effects on gastric and small intestine pH, acidified water at pH 4 and 5 lowered ileum and caecum pH (p < 0.05) compared to pH 3. Acidified water at pH 4 showed the highest (p < 0.05) pepsin activity compared to pH 3 and pH 5. Considering the limited sample size and short-term assessment period of our screening test, the OAs with the highest potential for use in post-weaning rabbits were FOR, ACET, and CIT at pH 4. The selected combinations did not exhibit any early adverse effects in young rabbits. These results should be further confirmed in a broader population of animals. It would also be advisable to extend the application of OAs over longer periods to evaluate their effects throughout the entire growing period of rabbits.

Quantification of Free Radicals from Vaping Electronic Cigarettes Containing Nicotine Salt Solutions with Different Organic Acid Types and Concentrations.

Electronic (e-) cigarette formulations containing nicotine salts from a range of organic acid conjugates and pH values have dominated the commercial market. The acids in the nicotine salt formulations may alter the redox environment in e-cigarettes, impacting free radical formation in e-cigarette aerosol. Here, the generation of aerosol mass and free radicals from a fourth-generation e-cigarette device was evaluated at 2 wt % nicotine salts (pH 7, 30:70 mixture propylene glycol to vegetable glycerin) across eight organic acids used in e-liquids: benzoic acid (BA), salicylic acid (SLA), lactic acid (LA), levulinic acid (LVA), succinic acid (SA), malic acid (MA), tartaric acid (TA), and citric acid (CA). Furthermore, 2 wt % BA nicotine salts were studied at the following nicotine to acid ratios: 1:2 (pH 4), 1:1 (pH 7), and 2:1 (pH 8), in comparison with freebase nicotine (pH 10). Radical yields were quantified by spin-trapping and electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra of free radicals in the nicotine salt aerosol matched those generated from the Fenton reaction, which are primarily hydroxyl (OH) radicals and other reactive oxygen species (ROS). Although the aerosol mass formation was not significantly different for most of the tested nicotine salts and acid concentrations, notable ROS yields were observed only from BA, CA, and TA under the study conditions. The e-liquids with SLA, LA, LVA, SA, and MA produced less ROS than the 2 wt % freebase nicotine e-liquid, suggesting that organic acids may play dual roles in the production and scavenging of ROS. For BA nicotine salts, it was found that the ROS yield increased with a higher acid concentration (or a lower nicotine to acid ratio). The observation that BA nicotine salts produce the highest ROS yield in aerosol generated from a fourth-generation vape device, which increases with acid concentration, has important implications for ROS-mediated health outcomes that may be relevant to consumers, manufacturers, and regulatory agencies.

Effects of isolated scenting on the taste quality of broken green tea based on metabolomics

Liquid chromatography-mass spectrometry (LC-MS) combined with multivariate analysis were used to characterize the nonvolatile compounds of broken green tea and explore the effect of isolated scenting on metabolic profile and taste quality of broken green tea in this research. A total of 236 nonvolatile compounds were identified and 13 compounds were believed to be the key characteristic taste compounds of scented broken green tea. Meanwhile, the optimal isolated scenting time of broken green tea was determined to be 10 h based on the sensory evaluation and PLS results. The contents and types of flavonoids, organic acids and catechins lead to the difference of taste quality at different scenting times. Overall, these findings provided a theoretical basis for scenting to improve the taste of broken green tea, and provide a new idea for improving the taste of broken green tea.

Dynamics of Water-Soluble Metals in Soil Moistened with Citrus Wastewaters Depends on Soil Reaction and Organic Acids

The demand for water for civil and industrial use is diminishing the availability of such a valuable environmental resource for agricultural purposes. Thus, for the next generation, it is imperative to find alternative water sources for crop irrigation. The citrus agroindustry utilizes a large amount of water for processing fruit (e.g., essential oil extraction, fruit washing). Wastewaters produced by citrus industry (CWWs) are rich in organic matter and mineral nutrients, thus making them potentially usable for crop irrigation. Conversely, due to their high content of organic acids and low pH, they may increase the availability of soluble metals, in the form of both plant nutrients and contaminants. The aim of this study was to evaluate the effect of CWWs on the dynamics of soil water-soluble metals and pH. To this end, CWWs from the processing of lemons, oranges, and tangerines at three different doses were used. CWWs were analyzed to investigate type and amount of organic acids. Soil water-soluble metals (Na, Mg, Al, K, Ca, Fe, Co, Ni, Cu, Zn, and Cd) and pH were determined at days 1, 3, 7, 21, and 28 after the addition of CWWs. Citric, ascorbic, oxalic, tartaric, acetic, and malic acids were found in CWWs, with citric acid being two orders of magnitude more concentrated than the other acids. After the addition of CWWs, soil pH promptly decreased from 7.2 to at least 5.3 depending on the type and concentration of CWWs. Concurrently, the concentration of almost all investigated metals sharply increased within 7 days after the addition of CWWs. Then, it decreased, reaching values similar to that of the control. The increase in metals availability as a consequence of pH decrease was ascribed to different causes: the exchange reaction between H+ and cations adsorbed onto colloid surfaces, the addition of organic matter by CWWs that stimulated microbial activity, and the quantity and type of organic acids added via CWWs. In conclusion, the obtained results suggest that the use of citrus wastewater for irrigation purposes could be a valid solution, with them being rich in plant nutrients and easily mobilized elements such as Ca, Mg, K, and Na. Further research is needed to refine the understanding of the impact of CWWs in the long term and to develop targeted strategies for managing industrial wastewater in agriculture.

Polybasic organic acids controlled synthesis of Mo-V-O composite metal oxide for the catalytic conversion of glycerol

By introducing oxalic acid, succinic acid, and tartaric acid into the synthesis process of Mo-V-O composite metal oxides, the structure directing effect of polybasic organic acids on the crystal structure of Mo-V-O compositee metal oxide was studied. Moreover, the prepared Mo-V-O samples with different crystal phase compositions were used to the conversion of glycerol, and the effect of crystal phase structure on its catalytic performance was investigated. Results show that the crystal phase structure of Mo-V-O can be regulated by changing the type and additive amount of polybasic organic acids. The crystal phase of Mo-V-O changed from MoV2O8 to Mo0.97V0.95O5 with the increase of succinic acid and tartaric acid. The change in the Mo-V-O crystal phase is related to the amount of organic acid and the carbon chain length. When the crystal phase is MoV2O8, the selectivity of acrolein and acetone is 25.7 % and 16.2 %. According to the XPS results, Mo6+ in MoV2O8 promoted the formation of acrolein, while Mo5+ in Mo0.97V0.95O5 promoted the formation of acetone. So when the crystal phase is Mo0.97V0.95O5, the selectivity of acrolein and acetone is 11.9 % and 24.6 %. Therefore, the results of catalyzing glycerol can be controlled by selecting different crystal phases.

Effects of Exogenous Organic Acids on the Soil Metabolites and Microbial Communities of Panax notoginseng from the Forest Understory

Panax notoginseng (Sanqi) is a precious traditional Chinese medicine that is commonly cultivated using conventional management methods in agricultural systems in Yunnan, China, where it faces the challenge of continuous cropping obstacles (CCOs). However, the existence of Sanqi CCOs in Sanqi–pine agroforestry systems remains unclear. Here, we applied three types of exogenous organic acids (phthalic acid, palmitic acid, and phthalic + palmitic mixed organic acids) mainly derived from the root exudates of Sanqi to simulate the CCOs; then, we compared the effects on plant growth, soil physicochemical properties, soil microbes, and soil metabolites. We found that organic acid concentrations of &gt;250 mg/kg reduced the fresh weight of Sanqi and the levels of total nitrogen, ammonium nitrogen, soil water content, total phosphorus, and pH value; these concentrations also increased the soil bacterial and fungal α-diversity. The type of organic acid, as opposed to the concentration and duration of treatment, had a vital impact on the structure of the bacterial and fungal community in Sanqi soils. Moreover, the organic acid concentrations of &gt;250 mg/kg also decreased the complexity and stability of the bacterial and fungal network. In addition, the metabolic pathways in the soils under different organic acids included 17 differential metabolites (DMs), which were involved in steroid hormone biosynthesis. The structural equation models (SEMs) revealed that plant growth, soil edaphic factors, and soil metabolites had direct or indirect influences on soil microbial communities under different organic acid conditions. Our results suggest that any phthalic or palmitic acid concentrations at concentrations &gt;250 mg/kg are detrimental to multiple aspects of Sanqi cultivation, confirming the presence of Sanqi CCOs in Sanqi–pine agroforestry systems.

Study ability of protection effect of organic acids for multi-metallic anti-corrosion additive system in ethylene glycol-water coolants

In this work, the electrochemical behavior of carbon steel, brass, bronze and aluminum alloys in the presence of various important organic acids (sebacic acid (SbA), terephthalic (TPA), 2-ethylhexanoic (E2C6A), and octanoic (C8A)) and the effect that these have on the growth and protectiveness of the alloys have been investigated. The results show that the presence of organic acids in the coolant increases the protective effect of the system by forming a film on the surface of the alloys. The EIS impedance results demonstrate the formation of active and passive protective layers on the surface of the alloys. The results of surveying 04 types of organic acids for the protection of different alloy substrates show that TPA and SbA acid additives are more effective than C8A and E2C5A. The additive C8A not only did not inhibit corrosion but also promoted this process strongly, especially with aluminum alloys and the TPA has the best anti-corrosion effect for steel, followed by C1 copper alloy and aluminum.

ANALISIS PEMBUATAN DAN POTENSI EKOENZIM KULIT BUAH JERUK NIPIS (Citrus aurantiifolia) SEBAGAI UPAYA PENINGKATAN KESEHATAN MANDIRI RUMAH TANGGA

Lime peel ecoenzyme (Citrus aurantifolia) is a microbial-based product made by fermenting the fruit peel for more than one month. The study aimed to analyze the ecoenzyme product from lime peel (C. aurantifolia) and its potential as an antiseptic so that it becomes one of the independent health improvement efforts on a household scale. The research design was laboratory experiments. The data described descriptively based on the results obtained from laboratory experiments. The research results showed that ecoenzyme contains a complex of organic ingredients as a natural antiseptic that can be used in the household such as 19 types of organic acids, 17 types of flavonoids, 16 types of carbohydrates and 19 types of amino acids which have potential as antiseptics. The study concluded that the ecoenzyme product from lime peel (C. aurantifolia) has potential as an antiseptic because it contains a complex of organic ingredients as a natural antiseptic that can be used in the household. Potential antiseptics can be in the form of dish cleaners, fruit and vegetable washes. Instead of being an antiseptic, ecoenzyme liquid can be used as a plant fertilizer and compost activator which can be applied to reduce household waste.

One-pot direct conversion of passion fruit hull into 5‑hydroxymethylfurfural catalysed by halogenated metal ionic liquids and organic acids

Biomass serves as a crucial source of renewable energy and potential raw materials for synthesizing various value-added chemicals. This study explored the direct conversion of the cellulose of passion fruit shells into 5-hydroxymethylfurfural (5-HMF), a promising substitute for fossil-derived compounds, by combining halogenated metal ionic liquids (ILs) and organic acids through one-pot hydrothermal reaction. Factors such as the type of ILs and organic acids, reaction time and temperature, as well as the quantity of dimethyl sulfoxide (DMSO) in the solvent, and the loading of substrate, IL, and organic acid were investigated for their impact on 5-HMF yield. Optimization of reaction conditions led to the attainment of the highest 5-HMF yield, reaching 33.1 ± 0.34 % based on the cellulose content within the passion fruit shell. Furthermore, the structural and morphological changes of the solid residues were analysed through techniques such as Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). These analyses revealed the progressive conversion of cellulose, hemicellulose, and lignin, accompanied by the formation of humin by-products. This integrated approach for 5-HMF production from agricultural waste introduced novel possibilities for transforming sustainable biomass resources into valuable chemical products.

Release of Potassium Ions from Feldspar by Organic Acids Present in Potassium-Solubilizing Bacteria

Agricultural production and quality are determined by the nutrient levels in the soil. Permanent agricultural lands are usually nutrient deficient and it is compensated by fertilization. Recent studies have found that potassium-bearing chemical fertilizers caused some environmental issues and these fertilizers are expensive. Therefore, the development of a new method for supplying potassium to plants using ingredients found in Sri Lanka is important. In this respect, the bioconversion of feldspar using biotechnological processing to obtain potassium fertilizers is very promising. The overall objective of this study is to explore the release of potassium ions from feldspar (Microcline- KAlSi3O8) found in Sri Lanka by organic acids present in potassium-solubilizing bacteria to improve the efficiency of these minerals to use in more sustainable agricultural practices. In this research, the solubilization of feldspar with citric, oxalic, succinic, and tartaric acids (the main acids that are produced by potassium solubilizing bacteria) was studied, concerning the effect of acid type, the effect of each acid concentration, the effect of particle size of feldspar, the effect of incubation time, and the changes in pH over time. Ground feldspar (0.150–0.300 mm and 0.075– 0.150 mm) was separately shaken with 0.01, 0.02, 0.03, 0.04 and 0.05 M of each organic acid for different periods (1, 2.5 and 4 hours) and the released potassium ion concentration was measured using a flame photometer and pH change was measured using a pH meter. The extent of solubilization of feldspar was shown to be influenced by the type of organic acid used. In comparison to inorganic acids (H2SO4), some organic acids were more successful in solubilizing feldspar. Both oxalic and tartaric acids showed a higher capability of releasing potassium from the feldspar than other acids by up to 9 folds. The solubilization was insignificant for the same acid when the acid concentration was changed. The solubility of feldspar in all acids increased as the particle size decreased. The solubilization of feldspar was increased practically in almost all acids as time increased. pH was increased in almost all acids when the reaction time was increased. These findings show that both oxalic and tartaric acids are the most successful acids in solubilizing feldspar. Finding bacteria that secrete these acids as their major byproducts and conditions that secrete these acids would be beneficial for agriculture and feldspar can be used to supply potassium to agricultural lands. &#x0D; Keywords: Organic acids, Feldspar, Solubilization

Potassium Ions Release from Mica by Organic Acids Present in Potassium Solubilizing Bacteria

Plants require a variety of life-building ingredients to grow properly and optimally. Plants that lack essential nutrients are unable to reach their full potential, have lesser yields, and are more susceptible to diseases. The primary macronutrients are nitrogen (N), phosphorus (P), and potassium (K), which are the three most critical nutrients without which plants wouldn‘t survive. Fertilizers must be added to K-depleted soil to produce a feasible soil environment for plant growth. Chemical K fertilizers are costly and cause soil pollution. Bio-fertilizers gaining popularity because of their low harmful effects. In Sri Lanka, new ways of producing Bio K-fertilizer are convenient in the field of agriculture. Phlogopite mica is a natural mineral that contains K as a major component (7.22% of mass as K2O) that can be used as the source of Bio-K fertilizer production. In this research, the solubilization of phlogopite mica (sample was obtained from Matale district, Sri Lanka) by major types of organic acids which are mainly released from bacteria was determined. In this study special attention was paid to the following main factors: Type of organic acids (Citric, Oxalic, Succinic and Tartaric acid), Acid concentrations (0.01 M, 0.02 M, 0.03 M, 0.04 M, and 0.05 M), Effect of ground mica particle sizes (0.300 mm-0.150 mm and &lt;0.150 mm), the effect of time on solubilization in three shaking time intervals (1 hour, 2.5 hours, 4 hours) the indicated solubilization patterns and pH changes were observed. The current findings show that Citric acid is the most efficient K solubilizer because at 0.04 M, citric releases the 17.00 mg/L of K whereas the lowest value of released K 2.33 mg/L was observed for oxalic acid which is determined by Flame Photometer using 50.00 mg/L of standard K+ solution. Therefore, Citric acid has a significant potential for the solubilization of K in mica. When particle size increases, the rate of solubilization appears to decrease with each acid. Also, when shaking time was increased the amount of soluble K released has been increased. Future studies of this research will be extended to find and isolation of citric acid-releasing bacteria for solubilizing mica to produce K Biofertilizer to improve soil fertility thereby increasing the crop yield in Sri Lanka. &#x0D; Keywords: Phlogopite mica, Bioconversion, Bio-fertilizers, Chemical K-fertilizers

Pollution Characteristics，Sources，and Secondary Generation of Organic Acids in PM2.5 in Zhengzhou

Organic acids in atmospheric particulate matter are widely involved in various physical and chemical reactions in the atmosphere and contribute greatly to the formation of secondary organic aerosols and haze pollutions. Therefore， the concentration distribution characteristics， sources， and secondary formation of organic acids in particulate matter are of great significance for further investigation of organic aerosols and their secondary transformation. Fine particulate matter （PM2.5） samples were collected in Zhengzhou， and three types of organic acids， including dicarboxylic acids， fatty acids， and resin acids， were analyzed to explore their species distribution， seasonal variations， source contribution， and secondary generation. Malonic acid （di-C3） and succinate acid （di-C4） were the most abundant in the identified dicarboxylic acids， which showed obvious seasonal variations in the order of summer &gt; autumn &gt; winter &gt; spring. Fatty acids had the highest concentration in winter and the lowest concentration in spring， showing obvious bimodal advantages， with the most abundant compounds being palmitic acid and stearic acid （C18）. Principal component analysis and multiple linear regression （MLR） were used to analyze the source of organic acids in PM2.5 in Zhengzhou； the results showed that 35% of the organic acids came from combustion and traffic sources， 24% from cooking sources， 23% from secondary formation， and 17% from natural sources. The ratios of the selected marker species （i.e.， di-C3 / di-C4， F/M， and C18：1 / C18） were used as tracers for the secondary formation of the organic aerosol and its aging process. The results showed that the photochemical reaction was intense in summer， and the proportion of organic aerosol aging or secondary production was high， whereas the photochemical reaction was weak in winter， and the aging degree of organic aerosol was low. Correlation analysis and MLR were used in combination to quantify the relative contribution of gas-phase oxidation and liquid-phase oxidation to dicarboxylic acid formation， and the results showed that gas-phase oxidation played a dominant role in the sampling period （accounting for 58%）， especially in summer （61%）.

Studies on Influence of Organic Acid Leaching Using CH3COOH and C4H6O6 on The Characteristics of Green Silica Produced for Sustainable Industrial Purpose

Rice husk is a biomass that constitutes 20-22% of Indonesia’s rice production by-products. Due to the low cost of raw materials and energy consumption, utilizing RH to produce silica can replace the production of synthetic silica. The type of organic acids used and the operating conditions during acid leaching play essential roles in the quality of green silica products. Temperature (28oC, 75oC) and duration (1h, 2h) treatment in acid leaching was applied with experimental method. Results showed the use of CH3COOH and C4H6O6 optimum to producing green silica with 92.21% purity, 61,25% of amorphous phase, increasing the surface area and pore volume of silica to 154,570 m2/g and 44.2513 cc/g. The highest silica yield reached at 99.26%, the whole analysis using SEM-EDX, XRD, and BETSAA. The highest moisture adsorption capacity of 825.6 mg/g meet the quality standard of SNI no. 06-2477-1991 for silica products with good adsorption quality. This study aims to explore the safer characteristics of green silica suitable for industrial purpose. The obtained results suggest applying organic acid leaching with CH3COOH and C4H6O6 can producing amorphous green silica. This method offers an alternative by using less hazardous materials, promoting environmentally friendly chemical processes in micro-scale production.

Phosphate solubilization and plant growth properties are promoted by a lactic acid bacterium in calcareous soil.

On the basis of good phosphate solubilization ability of a lactic acid bacteria (LAB) strain Limosilactobacillus sp. LF-17, bacterial agent was prepared and applied to calcareous soil to solubilize phosphate and promote the growth of maize seedlings in this study. A pot experiment showed that the plant growth indicators, phosphorus content, and related enzyme activity of the maize rhizospheric soils in the LF treatment (treated with LAB) were the highest compared with those of the JP treatment (treated with phosphate solubilizing bacteria, PSB) and the blank control (CK). The types of organic acids in maize rhizospheric soil were determined through LC-MS, and 12 acids were detected in all the treatments. The abundant microbes belonged to the genera of Lysobacter, Massilia, Methylbacillus, Brevundimonas, and Limosilactobacillus, and they were beneficial to dissolving phosphate or secreting growth-promoting phytohormones, which were obviously higher in the LF and JP treatments than in CK as analyzed by high-throughput metagenomic sequencing methods. In addition, the abundance values of several enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology, and Carbohydrate-Active Enzymes (CAZys), which were related to substrate assimilation and metabolism, were the highest in the LF treatment. Therefore, aside from phosphate-solubilizing microorganisms, LAB can be used as environmentally friendly crop growth promoters in agriculture and provide another viable option for microbial fertilizers. KEY POINTS: • The inoculation of LAB strain effectively promoted the growth and chlorophyll synthesis of maize seedlings. • The inoculation of LAB strain significantly increased the TP content of maize seedlings and the AP concentration of the rhizosphere soil. • The inoculation of LAB strain increased the abundances of the dominant beneficial functional microbes in the rhizosphere soil.

Effect of Type and Concentration of Organic Acids on Soil Bacteria Growth

The study was carried out at the University of Kufa - College of Agriculture for the season 2023-2022 to study the effect of the type and concentration of organic acids on the growth of soil bacteria, the first experiment includes the cultivation of bacteria on optional, broth, four types of organic acids were used (Citric acid, Acetic acid, Oxalic acid, Propionic acid) in concentrations (0,25.50.75.100.150) mM factor included four types of bacteria (Pseudomonas fluorescens, Acinetobacter calcoaceticus, Bacillus subtilis, Enterobacter cloacae). During this experiment, the minimum inhibitory concentration of these organic acids was determined, the second experiment included planting wheat seeds of a local variety by 4-2seeds per pot and used two types of organic acids (Acetic acid, Oxalic acid) and two types of pathogenic bacteria and biological resistance (Enterobacter cloacae and Bacillus subtilis). The results of the laboratory experiment showed a significant effect of organic acids in reducing the growth of bacteria, the addition of organic acids to the soil had a significant effect on the values of (Ec, PH) in the soil as oxalic acid obtained the highest rate of 6.370 dc m-1 At a concentration of 50 mM, oxalic acid obtained the highest rate of soil reaction score of 6.300 at a concentration of 75.50mM. The results indicate the significant effect of organic acids in inhibiting the total bacteria population in the soil, as oxalic acid obtained the highest rate of 106×114.3 g-1 dry soil at 50mM concentration.

Untargeted Metabolomics and Physicochemical Analysis Revealed the Quality Formation Mechanism in Fermented Milk Inoculated with Lactobacillus brevis and Kluyveromyces marxianus Isolated from Traditional Fermented Milk.

Traditional fermented milk from the western Sichuan plateau of China has a unique flavor and rich microbial diversity. This study explored the quality formation mechanism in fermented milk inoculated with Lactobacillus brevis NZ4 and Kluyveromyces marxianus SY11 (MFM), the dominant microorganisms isolated from traditional dairy products in western nan. The results indicated that MFM displayed better overall quality than the milk fermented with L. brevis NZ4 (LFM) and K. marxianus SY11 (KFM), respectively. MFM exhibited good sensory quality, more organic acid types, more free amino acids and esters, and moderate acidity and ethanol concentrations. Non-targeted metabolomics showed a total of 885 metabolites annotated in the samples, representing 204 differential metabolites between MFM and LFM and 163 between MFM and KFM. MFM displayed higher levels of N-acetyl-L-glutamic acid, cysteinyl serine, glaucarubin, and other substances. The differential metabolites were mainly enriched in pathways such as glycerophospholipid metabolism, arginine biosynthesis, and beta-alanine metabolism. This study speculated that L. brevis affected K. marxianus growth via its metabolites, while the mixed fermentation of these strains significantly changed the metabolism pathway of flavor-related substances, especially glycerophospholipid metabolism. Furthermore, mixed fermentation modified the flavor and quality of fermented milk by affecting cell growth and metabolic pathways.