PROCESS BIOCHEMISTRY
·
2015
·
IF 2.516
Xiang Zou,Jing Yang,Xu Tian,Meijing Guo,Zhenghua Li,Yunzheng Li
Polymalic acid (PMA) is a water-soluble biopolymer with many attractive properties for pharmaceutical applications. Its monomer, l -malic acid, is a potential C4 platform chemical, which is widely used in the food industry. In this study, a new strain with a high PMA yield from xylose was isolated and identified as Aureobasidium pullulans based on the morphological and phylogenetic analyzes. This strain produced PMA from xylose at a comparable or higher rate than glucose, and PMA produced from xylose had a similar molecular weight to that produced from glucose. A high final PMA titer of 80.4 g/L (91.2 g/L of malic acid after hydrolysis) was achieved using fed-batch fermentation with xylose in a 5-L fermentor at a PMA productivity of 0.52 g/L h. Corncob hydrolysate could be better utilized producing 28.6 g/L of PMA (or 32.4 g/L malic acid) in batch fermentation. PMA was further characterized for its chemical structure. This strain can be used to produce PMA and malic acid from xylose and lignocellulosic biomass hydrolysates.
研究领域:
生物化学
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工业微生物学
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产品关联
DOI
高影响因子
Brazilian Journal of Pharmaceutical Sciences
·
2023
·
IF 1.3
Mei Xuejiao,Lu Dingqiang,Yan Xiangping
L-Malic acid is the Active Pharmaceutical Ingredient of the latest generation of compound electrolyte injection (STEROFUNDIN ISO, Germany) and plays a very important role in the rescue of critically ill patients. The optical purity of L-malic acid is a Critical Quality Attributes. A new reversed-phase high performance liquid chromatography (RP-HPLC) method for pre-column derivatization of D-malic acid enantiomer impurity in L-malic acid bulk drug was established. The derivatization reaction was carried out using (R)-1-(1-naphthyl)ethylamine ((R)-NEA) as a chiral derivatization reagent. The Kromasil C18 column was used with a detection wavelength of 225 nm, a flow rate of 1.0 mL·min-1, and a column temperature of 30 °C. The mobile phase was acetonitrile-0.01 mol·L-1 potassium dihydrogen phosphate solution (containing 20 mmol·L-1 sodium heptanesulfonate, adjusted to pH 2.80 with phosphoric acid) (at a ratio of 45:55) and the resolution of D-malic acid and L-malic acid derivatization products reached 1.7. The proposed method possesses the advantages of simple operation, mild conditions, stable derivatization products and low cost. Also it gave better separation and was more accurate than previous methods.
研究领域:
药物分析
·
分析化学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2015
·
IF 2.679
Qi Zhang,Yang Yang,Limin Cheng,Cuicui Cao,Zhiwen Ding,Chunxiao Wang,Wenge Yang,Yonghong Hu,Yonglan Li
The solubility of dl -malic acid in binary solvent mixtures consisting of (methanol + acetonitrile); (methanol + N,N-dimethylformamide); and (methanol + isopropyl alcohol) was measured at temperatures ranging from (278.15 to 328.15) K by gravimetric method. Values of the solubility were fitted using modified Apelblat equation and Buchowski–Ksiazaczak λ h model. Computational results showed that the modified Apelblat equation was superior to the other equation. In addition, the thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy were calculated by the van’t Hoff analysis. This study provides valuable data for the dl -malic acid purification by the preferential crystallization procedure.
研究领域:
化学工程
·
物理化学
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产品关联
DOI
高影响因子
EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2014
·Vol. 239
·期 5
·827-835
·
IF 1.387
Wang Panxue,Li Aixia,Dong Mei,Fan Mingtao
The aim of this study was to purify a malolactic enzyme (MLE) from Oenococcus oeni ( O. oeni ) strain and determine its properties in detail. O. oeni SD-2a was cultivated in the ATB broth supplemented with 7 g/L l -malic acid for harvesting the cells. After harvest, the cells were washed and disrupted for purification of MLE. MLE was purified from the supernatant of the disrupted cells through protamine sulfate precipitation, anion exchange chromatography and gel filtration chromatography. The purified MLE was identified using mass spectrometry. The MLE was purified by 43-fold with a yield of 0.42 % and possessed a specific activity of 419.2 U/mg. The purified enzyme with a nominal molecular mass of 59 kDa and a theoretical p I of 4.76 exhibited a maximum enzyme activity at 35 °C and pH 6.0, which retained over 50 % of its initial activity in the presence of 14 % (v/v) ethanol. Mn 2+ was proven to be the most effective divalent cation to promote enzyme activity. Under the conditions of temperature 30 °C and pH 6.0, the K
m and V
max of MLE on l -malic acid were 12.5 × 10 −3 M and 43.86 μmol/(min × mg), respectively. Moreover, the purified enzyme exhibited a higher stability with 0.1 M NaCl in addition and had a half-life of 30 days at 4 °C.
研究领域:
微生物学
·
酶学
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产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2025
·
IF 12.5
Xinyi Chen,Xiaowei Zhang,Enpeng Li,Cheng Li
Physical, chemical, and dual modifications can all significantly affect the digestibility of isolated rice granules, while their effects on the starch digestibility of whole cooked rice grains remain elusive. Therefore, the impact of malic acid, ultrasound, and ultrasound + malic acid dual treatment on the starch digestibility of cooked rice grains with different starch molecular structures was investigated in this study. Ultrasound mainly caused cavitation on the surface of rice grains, promoting the leaching of materials (> 11 %) and amylose during cooking. This led to a faster retrogradation rate, smaller pores, and a lower maximum starch digestion extent. In contrast, malic acid caused a faster digestion rate due to the significant degradation of starch molecules, although its moderate esterification smoothed the cooked rice grain surface and slightly reduced the maximum starch digestion extent. Compared to malic acid treatment, the dual treatment showed a much higher degree of esterification, which may thus contribute to its significantly lower maximum starch digestion extent (up to 21 %). Collectively, these findings suggest that both ultrasound and dual treatment can be effective strategies for producing cooked rice grains with slower starch digestibility, with implications for improving the public health.
研究领域:
食品科学
·
营养学
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产品关联
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 11
·4190
·
IF 3.4
Yaxuan Ding,Nguyen Thi Hong Nhung,Jiahao An,Hao Chen,Lianying Liao,Chunlin He,Xinpeng Wang,Toyohisa Fujita
Lithium recovery is imperative to accommodate the increase in lithium demand. Salt lake brine contains a large amount of lithium and is one of the most important sources of lithium metal. In this study, Li2CO3, MnO2, and TiO2particles were mixed, and the precursor of a manganese–titanium mixed ion sieve (M-T-LIS) was prepared by a high-temperature solid-phase method. M-T-LISs were obtained by DL-malic acid pickling. The adsorption experiment results noted single-layer chemical adsorption and maximum lithium adsorption of 32.32 mg/g. From the Brunauer–Emmett–Teller and scanning electron microscopy results, the M-T-LIS provided adsorption sites after DL-malic acid pickling. In addition, X-ray photoelectron spectroscopy and Fourier transform infrared results showed the ion exchange mechanism of the M-T-LIS adsorption. From the results of the Li+desorption experiment and recoverability experiment, DL-malic acid was used to desorb Li+from the M-T-LIS with a desorption rate of more than 90%. During the fifth cycle, the Li+adsorption capacity of the M-T-LIS was more than 20 mg/g (25.90 mg/g), and the recovery efficiency was higher than 80% (81.42%). According to the selectivity experiment, the M-T-LIS had good selectivity for Li+(adsorption capacity of 25.85 mg/g in the artificial salt lake brine), which indicates its good application potential.Keywords:lithium-ion sieve;salt lake brine;DL-malic acid;ion exchange;lithium selectivity
研究领域:
材料科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Zhicheng Gao,Ying Li,Xunqiu Wang
In this study, the solubility of l -malic acid in three binary solvents (ethyl acetate + tetrahydrofuran , acetonitrile + tetrahydrofuran, butyl acetate + acetonitrile) at atmospheric pressure from T = (278.15 to 323.15) K was measured via a gravimetric method. The results show that in the temperature range studied, the solubility of l -malic acid in the selected solvent gradually increases with the increase of temperature. The solubility of l -malic acid increases with the increase of the mass fraction of tetrahydrofuran at the binary system (ethyl acetate + tetrahydrofuran, acetonitrile + tetrahydrofuran), the solubility of l -malic acid increases with The mass fraction of butyl acetate increases and decreases at the butyl acetate + acetonitrile system. In addition, the dissolution behavior of l -malic acid was explained using Hansen solubility parameter (HSP). Furthermore, the solubility data were correlated with using the modified Apelblat equation, the NRTL model and the newly proposed Apelblat-Sun model, the results have shown that the modified Apelblat equation has the best fitting effect. After research found, the hydrogen bonding force plays a key role in the solubility of l -malic acid. So solubility of l - resulted malic acid from the integrated effect of solute–solvent and solvent–solvent interactions. In addition, the van't Hoff equation was used to calculate and discuss all thermodynamic parameters of dissolution, Including standard Gibbs dissolution (Δ sol G o ), standard dissolution enthalpy (Δ sol H o ) and standard dissolution entropy (Δ sol S o ), Where Δ sol H o ，Δ sol S o ，Δ sol G o were all greater than 0, it have been shown that the dissolution process is driven by heat absorption and entropy. This study can provide basic thermodynamic data for the crystallization and industrial separation of l -malic acid.
研究领域:
化学工程
·
物理化学
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产品关联
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2014
·
IF 2.241
Ye Yuan,Yixin Leng,Hui Shao,Chunxiang Huang,Kai Shan
The solubility of dl -malic acid in water, ethanol and ethanol + water mixtures was investigated by a static analytical technique using the acid–base titration method at temperatures ranging from 298.15 to 333.15 K. The experimental results indicated that the solubility of dl -malic acid in the binary solvent mixtures increases with increasing temperature and decreases with increasing mass fraction of ethanol. The measured solid–liquid equilibrium (SLE) data were correlated by the modified Apelblat, λh and van’t Hoff equations. The calculated solubility demonstrated good agreement with the experimental data. It was found that the modified Apelblat equation could give the best correlation results, and subsequently used to derive the standard enthalpy, entropy and Gibbs energy change of solution of dl -malic acid in ethanol + water binary mixtures.
研究领域:
化学
·
热力学
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产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Xueqin Liao,Jianzhong Liu,Zexu Li,Mengxia Sun
Aluminum (Al) particles are widely used in propellants, thermite and pyrotechnics. However, commonly used micro Al has drawbacks such as agglomeration, high ignition temperature and slow burning rate, making its energy potential not fully exploited in applications. Therefore, exploring pathways to enhance the combustion of Al particles has become the focus at present. Herein, L -malic acid (LMA) was used to corrode the surface of Al particles to obtain a sample (named LMAl) with an average specific surface area of 11.456 m 2 /g (corresponding to Al particles with a diameter of 194 nm). The particle size distribution of LMAl did not change significantly compared to pristine Al. The XPS results showed that a small amount of LMA and corrosion products remained on the surface of the LMAl particles. Thermal analysis tests showed that the thermal oxidation rate and efficiency of LMAl was dramatically higher than that of pristine Al. Compared with the pristine Al, the combustion characterization parameters of LMAl such as combustion intensity, ignition delay time, maximum combustion temperature, mass burning rate and combustion efficiency were all improved. This trend was maintained after blending the ammonium perchlorate (AP). The condensed combustion products (CCPs) of Al revealed a large number of agglomerates and unburned Al particles. While many broken particles and tentacle-like structures were found in the CCPs of LMAl. Overall, compared to Al, the combustion of LMAl is significantly enhanced. The thermal reaction and combustion behaviors of the two are quite different. This study provides new insights into improving the ignition and combustion of Al.
研究领域:
材料科学
·
燃烧学
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产品关联
DOI
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2016
·
IF 2.624
Lei Zhou,Wei Liu,Zhiqiang Xiong,Liqiang Zou,Junping Liu,Junzhen Zhong,Jun Chen
Polyphenoloxidase (PPO) plays an important role in the browning of vegetables, fruits and edible fungi. The effects of ultrasound, malic acid, and their combination on the activity and conformation of mushroom ( Agaricus bisporus ) PPO were studied. The activity of PPO decreased gradually with the increasing of malic acid concentrations (5–60 mM). Neither medium concentrations (10, 20, 30 mM) malic acid nor individual ultrasound (25 kHz, 55.48 W/cm 2 ) treatment could remarkably inactivate PPO. However, the inactivation during their combination was more significant than the sum of ultrasound inactivation and malic acid inactivation. The inactivation kinetics of PPO followed a first-order kinetics under the combination of ultrasound and malic acid. The conformation of combination treated PPO was changed, which was reflected in the decrease of α-helix, increase of β-sheet contents and disruption of the tertiary structure. Results of molecular microstructure showed that ultrasound broke large molecular groups of PPO into small ones. Moreover, combined treatment disrupted the microstructure of PPO and molecules were connected together.
研究领域:
食品科学
·
生物化学
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DOI
高影响因子
CARBONATES AND EVAPORITES
·
2018
·Vol. 34
·期 3
·1131-1139
·
IF 0.947
Li Zhenxuan,Xiao Jiangtian,Huang Lidong,Xu Defu,Liu Dagang,Sun Xiaowen,Yu Luji,Wu Hongsheng
Succinic acid and l -malic acid are known to affect calcite dissolution/crystallization due to their tendency to adsorb on calcite’s surface. Taking into account the structural similarity among succinic acid, l -malic acid, and d -malic acid, a comparative study of their adsorption behavior on calcite was investigated for clarifying their adsorption mechanism. Kinetic results showed that l -malic acid adsorption reached equilibrium within 12 h, while succinic acid required 48 h. Results from the pH effect study showed that the strength of surface complex of succinic acid on calcite was weaker, even compared to its aqueous complex with Ca 2+ ion. Alternately, l -malic acid exhibited a much stronger surface complex strength, even compared to its aqueous complex with Ca 2+ ion. The adsorption isotherm results indicated that the saturated adsorption amount of l -malic acid was twice that of succinic acid, suggesting the surface complex of succinic acid may occupy a larger space on calcite surface compared to that of l -malic acid. Based on these results and those from previous studies, we proposed that succinic acid adsorption is through its two carboxyl groups binding to two adjacent surface sites (> Ca + ), and not only one. Also, l -malic acid adsorption occurs through one carboxyl group and one hydroxyl, which forms a “claw” on calcite surface. The similar adsorption behavior between l -malic acid and d -malic acid reinforces this proposition for l -malic acid adsorption mechanism. Our study will serve as good reference information to provide better understanding into the adsorption of other carboxylic acids on calcite.
研究领域:
地质学
·
化学
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DOI
高影响因子
CHEMICAL GEOLOGY
·
2020
·
IF 3.363
Weiyan Que,Bihe Wang,Feili Li,Xiujuan Chen,Hui Jin,Zanfang Jin
The accumulation of heavy metals by freshwater algae becomes more complex in the presence of dissolved organic matter but it is unclear how and to what extent. In this study, we comparatively assessed the effects of malic acid and citric acid on the bioaccumulation of Pb by Chlorella pyrenoidosa . A 6 h exposure experiment showed that adding organic acid (OA) to an algae–Pb binary system prolonged the adsorption equilibrium time and that the extended time was related to the concentration and number of carboxyl groups of the OA. A pseudo-second-order model fit the kinetic data well in the presence of OAs. The normality of carboxyl groups was negatively correlated with the bioaccumulation rate, k 2 , but positively correlated with the maximum bioaccumulation capacity, q max , of Pb following a linear equation, Y = 121.3x + 52.2, R 2 = 0.9877. Neither the Freundlich model nor the Langmuir model could fit the isotherm data in the presence of OA, suggesting that a new mechanism might exist. The quantitative relationship between bioaccumulated Pb and carboxyl group of OA indicated a stoichiometric relationship, which seemed to support the theory of a ternary complex of Pb, OA, and algal surface. Our results have added clarity to the current understanding of the accumulation of heavy metals by algae in freshwater ecosystems .
研究领域:
环境科学
·
水生生物学
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DOI
高影响因子
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