Types Of Organic Acids Research Articles

Comparison of Chiral Separations of Aminophosphonic Acids and Their Aminocarboxylic Acid Analogs Using a Crown Ether Column

Crown ethers are capable of complexing with primary amines and have been utilized in chromatography to separate amino acid racemates. This application has been extended to resolve (1-amino-1-phenylmethyl)phosphonic acid and (1-aminoethyl)phosphonic acid racemates, along with their aminocarboxylic acid analogs (2-phenylglycine and alanine, respectively), via a ChiroSil RCA crown ether based chiral stationary phase. Effects of the organic modifier, temperature, and acid type and concentration on retention and selectivity were also investigated. Trends in retention and selectivity varied between aminophosponic acids and their aminocarboxylic analogs. Computer modeling and (1)H NMR analyses were performed to potentially gain a better understanding of interactions of the aforementioned molecules with the ChiroSil RCA chiral stationary phase. Theoretical predictions of the most stable conformations for (R)- and (S)-enantiomers were compared to elution order; it was found that the elution order agreed with molecular modeling such that the longest retention correlated with the predicted most stable complex between the enantiomer and crown ether. (1)H NMR demonstrated interactions of aminophosphonic and aminocarboxylic racemates with (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid in solution and was utilized to determine enantiomeric excess of (1-amino-1-phenylmethyl)phosphonic acid after its enantioenrichment via crystallization through diastereomeric salt formation with the crown ether followed by filtration.

New model for flavour quality evaluation of soy sauce

The soy sauce samples established a model for its flavour quality evaluation. Initially, 39 types of flavour compounds, organic acids and free amino acids in six different types of soy sauce were identified and determined by HS-SPME GC/MS and HPLC. The model was developed based on the principal component analysis method for assessing and ranking of flavour quality of soy sauce. Using the principal component analysis which simplifies complex information, our correlative evaluation model was established, tested by comparing the traditional sensory evaluation method, providing a new methodology for objective evaluation of the flavour quality of soy sauce.  

Enhancing the Organoleptic and Functional Properties of Jujube by a Quick Aging Process

Black jujube was made by aging dried jujube and its physiochemical characteristics, antioxidant activities and α-glucosidase inhibitory activities were evaluated. The moisture and sugar contents were increased depending on the period of aging times and the pH was reduced thereby increasing acidity. The color of black jujube extract was changed from red to black resulting in decreases of Hunter color values L, a and b. As the aging progressed, sucrose was decomposed by increasing glucose and fructose, indicating higher contents of the total reducing sugars. Among the six different types of organic acids extracted from dried jujube, the levels of oxalic acid and citric acid were increased as the aging progressed. The total polyphenol contents in ethanol and water extracts of dried jujube were 7.74 and 8.12 mg/g, respectively. The water extract of black jujube aged for 48 hr contained the highest polyphenol contents at 16.82 mg/g. The 5’-hydroxymethylfurfural (5’-HMF) contents of black jujube extract significantly increased by longer aging times, and contained higher contents in the ethanol extract than water extract. The ethanol extract of black jujube showed the highest 5’-HMF content with 338.89 mg% after aging for 3 days. Also, IC50 values of black jujube aged for 72 hr evaluated by DPPH and ABTS radical assays were 0.54 and 0.59 mg/mL, respectively. α-Glucosidase inhibitory activities of black jujube at the concentration of 3.33 mg/mL (ethanol extract) increased from 65 to 80 % after aging for 72 hr.

Physiological, biochemical and growth responses of Italian ryegrass to butachlor exposure

A dose–response experiment was conducted to examine the effects of butachlor on the growth, physiology and biochemistry of Italian ryegrass. The plant suffered a >50% reduction in fresh biomass when exposed to a butachlor dose of 5mgL−1. However, a significant further biomass reduction only occurred when the dosage level of butachlor was increased to 40mgL−1. The root was more sensitive than the shoot to butachlor toxicity. It appears that the inhibition of fine root development under butachlor stress was the upstream cause for the retarded plant growth. A butachlor dose of 5mgL−1 was sufficiently high to cause significant H2O2-induced oxidative damage in the plant cells, as indicated by the increased MDA and the lower production rate relative to consumption rate of CAT. The plants tended to maintain sufficiently high levels of root activity and photosynthesis, and possibly relied on these mechanisms for survival in such a stressed environment. Butachlor had a stimulatory effect on the release of dissolved organic carbon but not amino acids from the plant roots. There were 5 types of organic acids in the root exudates, which all exhibited a trend to decrease with increasing level of butachlor.

Changes of the Intestinal Microbiota, Short Chain Fatty Acids, and Fecal pH in Patients with Colorectal Cancer

New molecular biology-based methods of bacterial identification are expected to help elucidate the relationship between colorectal cancer (CRC) and intestinal microbiota. Although there is increasing evidence revealing the potential role of microbiota in CRC, it remains unclear whether microbial dysbiosis is the cause or the result of CRC onset. We investigated the changes of intestinal environments in CRC or adenoma. We analyzed 13 groups of microbiota, 8 types of organic acids, and pH in feces obtained from the following 3 groups: individuals with CRC, adenoma, and non-adenoma. Ninety-three patients with CRC and 49 healthy individuals (22 with adenoma and 27 without adenoma) were enrolled. The counts of total bacteria (10.3 ± 0.7 vs. 10.8 ± 0.3 log10 cells/g of feces; p < 0.001), 5 groups of obligate anaerobe, and 2 groups of facultative anaerobes were significantly lower in the CRC group than in the healthy individuals. While the concentrations of short chain fatty acids (SCFAs) were significantly decreased in the CRC group, the pH was increased in the CRC group (7.4 ± 0.8 vs. 6.9 ± 0.6; p < 0.001). Comparison among the CRC, adenoma, and non-adenoma groups revealed that fecal SCFAs and pH in the adenoma group were intermediate to the CRC group and the non-adenoma group. Within the CRC group, no differences in microbiota or organic acids were observed among Dukes stages. CRC patients showed significant differences in the intestinal environment, including alterations of microbiota, decreased SCFAs, and elevated pH. These changes are not a result of CRC progression but are involved in CRC onset.

Updates on Antiobesity Effect ofGarciniaOrigin (−)-HCA

Garcinia is a plant under the family of Clusiaceae that is commonly used as a flavouring agent. Various phytochemicals including flavonoids and organic acid have been identified in this plant. Among all types of organic acids, hydroxycitric acid or more specifically (−)-hydroxycitric acid has been identified as a potential supplement for weight management and as antiobesity agent. Various in vivo studies have contributed to the understanding of the anti-obesity effects of Garcinia/hydroxycitric acid via regulation of serotonin level and glucose uptake. Besides, it also helps to enhance fat oxidation while reducing de novo lipogenesis. However, results from clinical studies showed both negative and positive antiobesity effects of Garcinia/hydroxycitric acid. This review was prepared to summarise the update of chemical constituents, significance of in vivo/clinical anti-obesity effects, and the importance of the current market potential of Garcinia/hydroxycitric acid.

Comparing Organic Acids and Salt Derivatives as Antimicrobials Against Selected Poultry-BorneListeria monocytogenesStrainsIn Vitro

This article reports on the antilisterial properties of selected organic acids and salt derivatives in order to suggest possible alternatives in food preservation and pathogen control in the poultry meat processing industry. The susceptibility of two Listeria monocytogenes isolates was assessed against five organic acids (lactic, acetic, malic, citric, and propionic) and two acid-salt derivatives (sorbic acid [potassium salt] and benzoic acid [sodium salt]) across a series of pH environments. Minimum inhibitory concentrations (MICs) of the acids were tested against the two strains by means of an agar-dilution method. In general, strain CC60 was found to be more resistant than strain CC77 to both organic acids and salts. At pH values of 7 and above, high MIC levels (low susceptibility) were noted for potassium sorbate, sodium benzoate, and lactic acids, whereas susceptibility at lower pH increased reaching pH5 where the isolates were susceptible to all the organic acids tested. A small increase in pH notably reduced antimicrobial activity against the organisms. At pH 7, the isolates just about lost susceptibility to benzoic, lactic, malic, and sorbic acids. Although the activity of the majority of acids was linked to pH, some acids were not as closely related (e.g., potassium sorbate, sodium benzoate, and citric acid), and this suggests that the type of organic acids plays a role in inhibition. The relatively high MICs reported for compounds that are conventionally used as preservatives against Listeria spp. raise concern. The results furthermore suggest that the type of organic acid used to set pH, and not only pH alone, plays a role in determining inhibition. It was confirmed that a "one size fits all" approach to preservation is not always effective. Furthermore, the need for microbiological data to the subspecies level to inform the selection of preservatives was highlighted.

Facile and direct synthesis of long-chain chitin from chitobiose via proton-assisted nonaqueous biocatalysis

Facile and direct enzymatic synthesis of long-chain chitin from chitobiose without activation of an anomeric carbon via traditional organic chemistry was first achieved in a one-step and one-pot reaction by the combined use of a surfactant-enveloped enzyme (SEE) and an organic protic acid co-catalyst in the aprotic nonaqueous solvent, N,N-dimethylacetamide. The SEE biocatalyst was successfully prepared by enveloping lysozyme, having chitinase activity, with sucrose oleate surfactant. When o-nitrobenzenesulfonic acid was used as a co-catalyst, a degree of polymerization of synthesized chitin reached ca. 210 in ca. 79% yield by proton-assisted SEE-mediated biocatalysis. The conversion ratios and average chain lengths depended on the types of organic protic acids, and high catalytic efficiencies were maintained in each case, resulting in high yields of ca. 40–80%. The SEE biocatalyst, which has enzymatic activity even in aprotic organic media containing strong organic acids, allowed the facile and high-yielding efficient synthesis of long-chain chitin from chitobiose in its original form. Therefore, proton-assisted SEE-mediated biocatalysis should prove useful for the glycosynthesis of many glycomaterials.

Evaluation of different kinds of organic acids and their antibacterial activity in Japanese Apricot fruits

The fruit of Japanese apricot is rich in organic acids, which have strong antibacterial activities. The types and contents of organic acids in six different cultivars of Japanese apricot fruit were evaluated by reverse-phase high performance liquid chromatography (HPLC). The antibacterial activity against Escherichia coli, Bacillus subtilis and Streptococcus suis was also determined. The results revealed that there are nine types of organic acids in the presence of the extracts of Japanese apricot fruit, including oxalic, tartaric, malic, ascorbic, acetic, citric, maleic, fumaric and succinic acids. The total organic acid content of ‘Zhonghong’ was the highest among the studied cultivars, and the main organic acids present were citric and malic acids. The antibacterial activity on the growth of E. coli and B. subtilis was higher than on the growth of S. suis. The antibacterial effect of acetic acid against bacteria was the best, and the minimum antibacterial concentration (MIC) against E. coliand B. subtilis was 0.417 mg/mL. The citric and maleic acids were also against these three strains of bacteria. The results suggest that the antibacterial activity is related to the organic acid composition and content of Japanese apricot fruit. Key words: Japanese apricot, organic acids, high performance liquid chromatography (HPLC), antibacterial activity.

585P - Changes in the Intestinal Environments of Patients with Colorectal Cancer or Adenoma

ABSTRACT Background An increasing amount of evidence suggests a role for microbiota in colorectal cancer (CRC). However, it remains unclear whether microbial dysbiosis is the cause or the result of CRC onset. We analyzed the intestinal environments to determine whether the changes differed with the stage of CRC. Patients and methods We analyzed 13 groups of microbiota, 8 types of organic acids, and pH in fecal matter obtained from the following groups: individuals with CRC, individuals with adenoma, and individuals with normal intestinal tracts. Ninety-three patients with CRC and 49 healthy individuals (22 with adenoma and 27 without adenoma) were enrolled. The fecal microbiota was identified using reverse transcription-quantitative PCR. Results The counts of total bacteria (10.3 ± 0.7 vs. 10.8 ± 0.3 log10 cells/g of feces; P Conclusions CRC patients showed significant changes in the fecal microbiota, SCFA concentrations, and pH. These changes are not a result of CRC progression but are involved in CRC onset. Disclosure All authors have declared no conflicts of interest.

Effects of organic acids on Cd adsorption and desorption by two anthropic soils

The objective of this experiment was to study the effects of malic, tartaric, oxalic, and citric acid on the adsorption and desorption characteristics of Cd by two typical anthropic soils (lou soil and irrigation-silted soil) in North-west China. Cadmium adsorption and desorption were studied under a range of temperatures (25°C, 30°C, 35°C, 40°C), organic acid concentrations (0.5–5.0 mmol·L−1), and pH values (2–8). The results showed that the Cd adsorption capacity of the lou soil was significantly greater than that of the irrigation-silted soil. Generally, Cd adsorption increased as the temperature increased. In the presence of NaNO3, the adsorption of Cd was endothermic with ΔH values of 31.365 kJ·mol−1 for lou soil and 28.278 kJ·mol−1 for irrigation-silted soil. The endothermic reaction indicated that H bonds were the main driving force for Cd adsorption in both soils. However, different concentrations of organic acids showed various influences on the two soils. In the presence of citric acid, chemical adsorption and van der Waals interactions were the main driving forces for Cd adsorption rather than H bonds. Although the types of organic acids and soil properties were different, the effects of the organic acids on the adsorption and desorption of Cd were similar in the two soils. The adsorption percentage of Cd generally decreased as organic acid concentrations increased. In contrast, the adsorption percentage increased as the pH of the initial solution increased. The exception was that adsorption percentage of Cd increased slightly as oxalic acid concentrations increased. In contrast, the desorption percentage of Cd increased with increasing concentrations of organic acids but decreased as the initial solution pH increased.

Model organic compounds differ in priming effects on alkalinity release in soils through carbon and nitrogen mineralisation

The influence of organic matter and its cycling on soil pH change is still unclear. This study investigated the effect of organic compounds on carbon and nitrogen dynamics and their relationship with pH changes in two soils differing in initial soil pH (Podosol of pH 4.5 and Tenosol of pH 6.2). Seven organic compounds representing common compounds in decomposing plant residues or root exudates were added to the soils and incubated for 60 d. The largest cumulative soil respiration occurred when glucose, malic acid and citric acid were added. In addition, the Tenosol had the greater respiration compared to the Podosol. The addition of organic acids (acetic, malic, citric, ferulic and benzoic acid) instantly decreased soil pH due to the dissociation of H+ from the acids. The pH of both soils was then restored over time, which was positively correlated with decomposition % of these compounds. The pH of the Tenosol amended with all the organic acids and of the Podosol with malic acid exceeded that of the control, and net alkalization occurred, with the degree of alkalization being greater with malic and citric acid. Adding organic acids to the Tenosol generally increased NH4 concentrations but decreased NO3 concentrations. The addition of glucose decreased pH in Podosol but slightly increased it in the Tenosol. The addition of glucosamine hydrochloride decreased pH due to significant nitrification. The results suggest that the addition of organic acids stimulates microbial NO3 uptake, and ammonification and decomposition of indigenous soil organic matter, resulting in a priming effect on alkalinity release, and that the degree of the priming effect is influenced by the type of organic acid and initial soil pH.

Zinc chemical forms and organic acid exudation in non-heading Chinese cabbages under zinc stress

As an essential element, zinc also is a heavy metal. Non-heading Chinese cabbage showed obvious tolerance to Zn stress in former research. To further understand the mechanisms involved in Zn adaptability and detoxification, two genotypes Suzhouqing and Aijiaohuang were selected to investigate the chemical forms of Zn and root exudation. Zinc stress obvious strained the plant growth, and Aijiaohuang was more injured than Suhouqing under Zn stress. Under normal Zn levels, the chemical forms of Zn were diverse in three organs between genotypes. Results showed extractions of 2% HAc, 80% ethanol and 1 M NaCl were separately dominant in roots, petioles and leaves. However, under Zn stress (13 mg·L–1 and 52 mg·L–1) most of the Zn was extracted by 1M NaCl, and the subdominant amount of Zn was extracted by 80% ethanol. In the control only four types of organic acid could be detected. While under Zn stress, oxalic acid, tartaric acid, malic acid, lactic acid, acetic acid, citric acid and amber acid were all detected, so it could be speculated Zn detoxification with organic ligands or integrated with pectates and proteins in cells might be responsible for the adaptation of Zn stress in Chinese cabbage.

코발트 정광(精鑛)으로부터 유기산(有機酸)을 이용(利用)한 Co, Cu, Ni, Al, Fe의 화학적(化學的) 침출(浸出)

코발트 정광으로부터 코발트와 구리의 회수를 위한 환경친화적인 침출공정 개발의 일환으로 유기산을 침출제로 사용하여 각 금속의 침출 거동에 대하여 기초 연구를 실시하였다. 주요 실험 변수로는 유기산 종류 및 농도, 반응 시간 및 온도 그리고 고액농도비 등 코발트와 구리의 침출에 영향을 미칠 수 있는 인자들에 대하여 고찰하여 최적 조건을 얻고자 하였다. 실험 결과 유기산중 구연산이 코발트 및 구리의 침출에 효과적이었다. 한편, 구연산을 이용한 침출실험 결과 구연산의 농도가 2.0M에서 코발트 99 %, 구리 95%, 니켈 70%의 높은 침출율을 나타내었다. 또한, 과산화수소는 약 3 vol. % 정도 첨가하는 것이 적당하였고, 최적 반응온도는 <TEX>$70^{\circ}C$</TEX>이었다. Enviromental friendly leaching process for the recovery of cobalt and copper from the cobalt concentrate was investigated by organic acids as a leaching reagent. The experimental parameters, such as organic acid type, concentrations of leachant, time and temperature of the reaction as well as the solid to liquid ratio were tested to obtain the optinum conditions for the leaching of cobalt and copper. The results showed that citric acid was the most effective leaching reagent among the organic acids used in this experiment. About 99% of cobalt, 95% of copper and 70% of nickel was dissolved by 2.0 M of citric acid. Addition of 3.0 vol.% of hydrogen perioxide was effective to enhance the leaching efficiency and the optinum temperature was found to be about <TEX>$70^{\circ}C$</TEX>.

Mesoporous Activated Carbon Structure Originated from Cross-Linking Hydroxyethyl Cellulose Precursor by Carboxylic Acids

Mesoporous matrixes of activated carbon (AC) are normally synthesized using the hard or soft template method. This work explores a template-free method to synthesize a mesoporous AC matrix through creating interchain bonding in its precursor. Hydroxyethyl cellulose (HEC) was adopted as a precursor, and its polymer chains were covalently cross-linked by the esterification reaction. Four types of organic carboxylic acids were used to examine the effect of esterification cross-linking on the formation of a mesoporous structure primarily through the course of pyrolysis. The BET surface analysis of the resulting ACs reveals an explicit correlation between the number of carboxylic acid groups on a benzene ring and the mesoporous structures of a synthesized AC. Moreover, it is also found that an optimal cross-linking degree for attaining the maximum volume fraction of mesopores exists with respect to each type of the cross-linker used. An attempt was made to understand how a cross-linked HEC is converted to a porous structure of an AC. The mesoporous structures of the ACs synthesized were also assessed by their capability of stripping H2S from a gas stream.

폐(廢)리튬이온전지(電池) 양극활물질(陽極活物質)에서 유기산(有機廳)을 이용(利用)한 코발트 및 리튬의 화학적(化學的) 침출(浸出)

페리튬이온전지 양극활물질인 <TEX>$LiCoO_2$</TEX>로부터 코발트와 리튬을 회수하기 위한 기초 연구로 환경친화적인 유기산을 이용하여 코발트와 리튬의 침출에 관한 연구를 실시하였다. 주요 실험 변수로는 유기산 종류 및 농도, 과산화수소 농도, 반응 시간 및 온도 그리고 고액농도비 등 코발트와 리튬의 침출에 영향을 미칠 수 있는 인자들에 대하여 고찰하여 최적 조건을 얻고자 하였다. 실험 결과 사용한 유기산중에서 Latic acid가 코발트 및 리튬의 침출율이 99.9%로 가장 우수 하였다. 한편, 구연산을 이용하여 창출 실험한 결과에서 과산화수소의 농도, citric acid의 농도 및 반응온도가 증가함에 따라 코발트 및 리튬의 침출율이 증가하였다. 그러나 고액농도비가 증가함에 따라 침출율은 감소하는 경향을 보였다. Environmental friendly leaching process for the recovery of cobalt and lithium from the <TEX>$LiCoO_2$</TEX> was investigated by organic acids as a leaching reagent. The experimental parameters, such as organic acid type, concentrations of leachant and hydrogen peroxide, reaction time and temperature as well as the pulp density were tested to obtain the most effective conditions for the leaching of cobalt and lithium. The results showed that the latic acid was the most effective leaching reagent for cobalt and lithium among the organic acids and was reached about 99.9% of leaching percentage respectively. With the increase of the concentration of citric acid, hydrogen peroxide and temperature, the leaching rate of cobalt and lithium increased. But the increase of pulp density decreased the leaching rate of cobalt and lithium.

Effects of organic acids and starch water ratios on the properties of retrograded maize starches

The effects of organic acid types and concentrations as well as starch water ratios on resistant starch (RS) levels and the properties of retrograded maize starches were studied. The pH of the starch slurry decreased with increasing water ratio and organic acid concentration, but the addition of succinic acid slightly reduced pH compared to the other organic acids. The RS level of RS3 was increased 160–169% for the high starch ratio and was increased 137–146% for the low starch ratio with organic acid addition (p<0.01). The color difference between the RS3 powder added with citric acid and native starch showed the lowest value. All samples had B type crystallinity. Their swelling power and solubility increased, but the water binding capacity decreased with organic acid addition. The added organic acids rapidly decreased the pasting viscosity of RS3, but patterns were different by organic acid type (succinic acid) and starch water ratio.

Phase-controlled synthesis of monodispersed porous In2O3 nanospheres via an organic acid-assisted hydrothermal process

Phase-pure porous nanospheres, both In(OH)3 and InOOH, have been prepared through a facile hydrothermal method using different organic acids as the assistant agents. The organic acids play an important role in the phase change, and the phase composition of the precursors could be deliberately controlled by adjusting the organic acid (citric acid or tartaric acid). Cubic and hexagonal In2O3 monodispersed nanospheres with porosity can be obtained from In(OH)3 and InOOH, respectively, while size and morphology can be maintained to a certain extent. The as-synthesized porous In2O3 nanospheres are composed of numerous small nanocrystallites and possess good size uniformity. Influencing factors such as the reaction time and the type and amount of organic acids were systematically investigated. A possible ethylenediamine or tartaric acid coordinated mechanism of the phase-control synthesis of In2O3 was proposed based on the experimental results. Furthermore, the potentialities of the porous In2O3 nanospheres were also studied by room-temperature photoluminescence (PL) spectroscopy.

돈분 슬러리의 저장형태 및 온도에 따른 가용화 특성

본 연구에서는 돈분 슬러리의 저장형태 및 온도에 따른 유기물의 거동을 관찰하였는데, closed system과 open system의 저장형태에 따른 유기물 농도는 <TEX>$20^{\circ}C$</TEX>에서 30일 저장 후 약 2배 정도의 차이를 보였다. 또한 온도에 의한 유기물 농도의 거동은 온도가 증가할수록 TS 및 VS 농도가 감소하였고, <TEX>$20^{\circ}C$</TEX> 약 23%, <TEX>$35^{\circ}C$</TEX> 약 29% 정도가 감소되는 것으로 나타났다. 하절기 외부온도 특성을 반영한 온도조건(20, <TEX>$35^{\circ}C$</TEX>) 및 저장기간 따른 생성된 유기산 종류는 비슷하였고, 저장기간 15일 이후부터 분변내 포함된 가수분해 및 산생성 미생물의 성장이 증대되어 유기산의 생성이 증가하였다. 반응시간 30일 후 생성된 총유기산 농도는 <TEX>$20^{\circ}C$</TEX>에서 <TEX>$2,829\;mg{\cdot}COD/L$</TEX>이었으며, <TEX>$30^{\circ}C$</TEX>에서는 <TEX>$9,123\;mg{\cdot}COD/L^{\circ}C$</TEX>로 초기 유기물농도 대비 각각 5.4, 17.4%의 유기산 전환율을 나타내었다. 따라서 돈분슬러리의 저장기간이 길어질수록 외부온도에 따라 가수분해 및 산생성 반응으로 유기산이 생성되고, 메탄생성균의 기질이용으로 유기물의 손실이 발생하여 온실가스 배출도 증가할 것으로 예상된다. The current study investigated the fate of organic matter in piggery slurry under two different store systems(closed store system and open store system) in association with different temperature. Thirty days after storing in both systems at <TEX>$20^{\circ}C$</TEX>, it was observed that the content of organic matter remained in piggery slurry with closed store system was twice more than that with open store system implying more efficient degradation of organic matter with open store system. Temperature also influenced on the organic matter degradation in piggery slurry as shown decline in TS and VS contents as the temperature increased. With store at <TEX>$35^{\circ}C$</TEX>, 29% of initial organic matter was reduced while there was only 23% reduction of organic matter at <TEX>$20^{\circ}C$</TEX>. There was no difference in the type of organic fatty acids(VFAs) produced under the range of temperature(20, <TEX>$35^{\circ}C$</TEX>) simulating summer condition. Increases in organic fatty acids contents with hydrolysis and acid producing microbial was observed from 15 days after initiating store of the piggery slurry and the total organic acid amount produced 30 days after store was <TEX>$2,829\;mg{\cdot}COD/L$</TEX> and <TEX>$9,123\;mg{\cdot}COD/L$</TEX> at <TEX>$20^{\circ}C$</TEX> and <TEX>$35^{\circ}C$</TEX>, respectively. These corresponded to 5.4% and 17.4% of the initial organic matter contents in piggery slurry, respectively.

Soil fungal isolates produce different organic acid patterns involved in phosphate salts solubilization

Phosphorus availability is a major limiting factor for yield of most crop species. The objective of this study was to compare the solubilization of three sources of phosphorus (P) by different fungal isolates and to determine the possible mechanisms involved in the process. Talaromyces flavus (S73), T. flavus var flavus (TM), Talaromyces helicus (L7b) and T. helicus (N24), Penicillium janthinellum (PJ), and Penicillium purpurogenum (POP), fungal strains isolated from the rhizosphere of crops, are known to be biocontrol agents against pathogenic fungi. The P solubilization efficiency of these fungal strains in liquid media supplemented either with tricalcium phosphate (Ca3(PO4)2; PC), aluminum phosphate (AlPO4; AP), or phosphorite (PP) depended on the source of P and the fungal species. The type and concentration of organic acids produced by each species varied according to the source of available P. In the medium supplemented with PC, the highest proportion was that of gluconic acid, whereas in the media supplemented with the other P sources, the highest proportion was that of citric and valeric acids. This suggests that the release of these organic compounds in the rhizosphere by these microorganisms may be important in the solubilization of various inorganic P compounds. Results also support the hypothesis that the simultaneous production of different organic acids by fungi may enhance their potential for solubilizing insoluble phosphate.