Effect of salts on the extraction characteristics of succinic acid by predispersed solvent extraction

Predispersed solvent extraction (PDSE) of succinic acid with Tri-n-octylamine (TOA) dissolved in 1-octanol from aqueous solutions of 50 g/L succinic acid was examined. It was found that the equilibrium data in PDSE was equal to that in conventional solvent extraction in spite of the lack of mechanical mixing in PDSE. The influence of salts on succinic acid extraction and the stability of colloidal liquid aphrons (CLAs) were also investigated. Results indicated that in the presence of sodium chloride, less succinic acid was extracted by CLAs and the stability of CLAs decreased. However, the stability of CLAs was sufficient to make PDSE practically applicable to real fermentation broth, considering the concentration range of salts in the fermentation process for succinic acid.     

Predispersed solvent extraction of succinic acid aqueous solution by colloidal liquid aphrons in column

A study of the PDSE (predispersed solvent extraction) for succinic acid by colloidal liquid aphrons was conducted. The organic phase contaning TOA (tri-n-octylamine) and 1-octanol permits a selective extraction of succinic acid from its aqueous solution. There was no difference of the extractability of PDSE and that of conventional mixer-settler type extraction. Taking into account the no mechanical mixing in PDSE, it was concluded that the PDSE process is more adaptive than the conventional mixer-settler type extraction process. From mass transfer analysis at the various concentration of TOA in counter-current continuous operation, the concentration of TOA had no influence on the mass transfer coefficient. The loading values in continuous PDSE were almost same as those in batch operation.     

Selective extraction of acetic acid from the fermentation broth produced by Mannheimia succiniciproducens

Acetic acid is by-product from fermentation processes for producing succinic acid using Mannheimia succiniciproducens . To obtain pure succinic acid from the final fermentation broth, acetic acid was selectively removed based on the different extractability of succinic acid and acetic acid with pH using tri-n-octylamine (TOA) as extractant. When successive batch extractions were performed using 0.25 mol TOA kg(-1) dissolved in 1-octanol at pH 5, the mol ratio of succinic acid to acetic acid before extraction was 4.9 and the final ratio after the fourth batch was 9.4.     

Kinetics of the extraction of succinic acid with tri-n-octylamine in 1-octanol solution

Kinetic studies for the extraction of succinic acid from aqueous solution with 1-octanol solutions of tri-n-octylamine (TOA) were carried out using a stirred cell with a microporous hydrophobic membrane. The interfacial concentrations of species were correlated and thus the intrinsic kinetics was obtained. The overall extraction process was controlled by the chemical reaction at or near the interface between the aqueous and organic phases. The formation reaction of succinic acid-TOA complex was found to be first order with respect to the concentration of succinic acid in the aqueous phase and the order of 0.5 with respect to that of TOA in the organic phase with a rate constant of (3.14 +/- 0.6) x 10(-8) m(2.5) x mol(-0.5) x s(-1). The dissociation reaction of succinic acid-TOA complex was found to be the second-order with respect to that of succinic acid-TOA complex in the organic phase and the order of -2 with respect to that of TOA in the organic phase with a rate constant of (1.44 +/- 1.4) x 10(-4) mol x m(-2) x s(-1).     

Linear solvation energy relationship modeling and kinetic studies on reactive extraction of succinic acid by tridodecylamine dissolved in MIBK

Equilibrium and kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in MIBK are reported. All measurements were carried out at 298.15 K. The extent to which the organic phase may be loaded with succinic acid is expressed as a loading ratio, Z. The equilibrium data were also interpreted by a proposed mechanism of three reactions of complexation by which (1:1) and (2:1) acid-amine complexes are formed. Kinetics of extraction of succinic acid by tridodecylamine in MIBK has also been determined. Kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in MIBK were carried out using a stirred cell for kinetic studies. The results of the liquid-liquid equilibrium measurements were correlated by a linear solvation energy relationship (LSER) model, which takes into account physical interactions. From the regression coefficients, information on the solvent-solute interaction is obtained and solvation models are proposed.     

Reactive extraction of succinic acid with tripropylamine (TPA) in various diluents

Succinic acid is of interest as the raw material of polysuccinate which is a biodegradable polymer. The tripropylamine (TPA) was used as the extraction agent for the reactive extraction of succinic acid in various alcohol diluents. Equilibrium and loading data for various active diluents were obtained at various TPA concentrations. At the same TPA concentration the extractabilities of TPA increased as the number of carbon in alcohols decreased. It was explained by decreasing solubility of acid-amine complex due to decreasing polarity with increasing the number of carbon in alcohols. The type of succinic acid-amine-diluent complex was predicted by the value of loading with various concentration of TPA/various alcohols.     

Effect of operating variables on back-extraction characteristics of succinic acid from organic phase

Tri-n-octylamine (TOA) is an effective extractant for the recovery of succinic acid from fermentation broth. The recovery of succinic acid from organic phase depends on the operating variables such as temperature, pH, volume of aqueous phase, and use of displacer. In thermal recovery of succinic acid, 34% of succinic acid was recovered at 90°C. More than 90% of succinic acid was back-extracted by pH-swing. Efficiency of back-extraction was increased 23% as increasing volume of aqueous phase. Use of oleic acid as a displacer increased efficiency of back-extraction to 76%. Aqueous phase volume and concentration of oleic acid were controlled simultaneously to increase the efficiency of back-extraction and percent recovery of succinic acid reached to 90.     

Equilibrium studies on reactive extraction of succinic acid from aqueous solutions with tertiary amines

Reactive extraction of succinic acid from aqueous solutions with various tertiary amines dissolved in 1-octanol and n-heptane has been studied as a function of the acid concentration and the chain length of tertiary amine. When 1-octanol was used as diluent, the extractability of the tertiary amine was proportional to the chain length of tertiary amine at the same concentration of amines. The loading values were also proportional to the chain length of tertiary amine. However, when n-heptane was used as diluent, the extractability and loading values of the tertiary amine were inversely proportional to the chain length of amines. It was due to the aggregate formation of the acid-amine complex.     

Extraction of succinic acid with 1-octanol/n-heptane solutions of mixed tertiary amine

The reactive extraction of succinic acid was carried out by mixed tertiary amine which consisted of tripropylamine (TPA) and trioctylamine (TOA) as the extraction agent in 1-octanol/n-heptane diluent. Maximum distribution coefficient was obtained at 8:2 weight ratio of TPA/TOA. At this ratio, its extraction efficiency is above 90% at the 3.9 wt.% of succinic acid in aqueous solution. Furthermore, the prevention of the third phase formation made the phase separation between organic phase and aqueous phase easy.     

Batch and continuous fermentation of succinic acid from wood hydrolysate by Mannheimia succiniciproducens MBEL55E

Batch and continuous cultures of Mannheimia succiniciproducens MBEL55E were carried out in a complex medium containing a NaOH-treated wood hydrolysate for the production of succinic acid. The wood hydrolysate based medium was treated with NaOH before sterilization to reduce the formation of inhibitory compounds. M. succiniciproducens MBEL55E utilized xylose as well as glucose in the wood hydrolysate based medium as a carbon source for the succinic acid production. In batch cultures, the final succinic acid concentration of 11.73 g l⁻¹ was obtained from the pre-treated wood hydrolysate based medium, resulting in a succinic acid yield of 56% and a succinic acid productivity of 1.17 g l⁻¹ h⁻¹, while the corresponding continuous cultures gave the succinic acid yield and productivity of 55% and 3.19 g l⁻¹ h⁻¹, respectively. These results suggest that succinic acid can be produced economically and efficiently by the fermentation of M. succiniciproducens MBEL55E from an inexpensive biomass-based wood hydrolysate.     

Fermentative production of succinic acid from glucose and corn steep liquor byAnaerobiospirillum succiniciproducens

Anaerobiospirillum succiniciproducens requires expensive complex nitrogen sources such as yeast extract and polypeptone for its growth and succinic acid production. It was found thatA. succiniciproducens was able to grow in a minimal medium containing glucose when supplemented with corn steep liquor (CSL) as the sole complex nitrogen source. The concentration of CSL had a significant effect on the glucose consumption byA. succiniciproducens. When 10–15 g/L of CSL was supplemented, cells were grown to an OD₆₆₀ of 3.5 and produced 17.8 g/L succinic acid with 20 g/L glucose. These results are similar to those obtained by supplementing yeast extract and polypeptone, thereby suggesting that succinic acid can be produced more economically using glucose and CSL.     

Reactive extraction of lactic acid with mixed tertiary amine extractants

The mixture of tripropylamine (TPA) and trioctylamine (TOA) dissolved in 1-octanol/n-heptane was used in the reactive extraction of (L+)lactic acid in aqueous solution. Maximum distribution coefficients were obtained in the range from 6:4 to 8:2 weight ratio of TPA/TOA at 5% (w/w) lactic acid in aqueous phase and their extraction efficiencies were above 90%. By introducing TPA into TOA, the third phase formation could be overcome, thereby, the settling time is shorter than in the case of TOA only.     

Integrated separation process for isolation and purification of biosuccinic acid

Biotechnologically produced succinic acid has the potential to displace maleic acid and its uses. Therefore, it is of high interest for the chemical, pharmaceutical, and food industry.In addition to optimized production strains and fermentation processes, an efficient separation of succinic acid from the aqueous fermentation broth is indispensable to compete with the current petrochemical production of succinic acid. Isolation and purification of succinic acid from an Escherichia coli fermentation broth were studied with two amine-based reactive extraction systems: (i) trihexylamine in 1-octanol and (ii) diisooctylamine and dihexylamine in a mixture of 1-octanol and 1-hexanol. Back extraction of succinic acid from the organic phase was carried out using an aqueous trimethylamine solution. The trimethylammonium succinate generated after back extraction was split with an evaporation-based crystallization.The focus was on process integration, for example, reuse of the applied amines for extraction and back extraction. It was shown that the maximum trimethylamine concentration for back extraction should not exceed the stoichiometric amount (2 mol trimethylamine/mol the succinic acid in the organic phase) to ensure maximal extraction yields with the reused organic phase in subsequent extractions. Moreover, mixer-settler extraction and back extraction of succinic acid were scaled up from the milliliter- to the liter-scale making use of liquid–liquid centrifuges. The overall yield was 83.5% of the succinic acid from thefermentation supernatant. The final purity of the succinic acid crystals was 99.5%. Organic phase and amines can easily be recycled and reused.     

碳酸盐对谷氨酸产生菌在缺氧条件下产有机酸的影响

考察谷氛酸产生菌在缺氧条件下积累L-乳酸和琥珀酸的情况.结果表明:在缺氧条件下,嗜乙酰乙酸棒杆菌(Corynebacterium acetoacidophilum)ATCC 13870积累有机酸的浓度随菌体密度的增大而增加,其中琥珀酸和乳酸积累的最适pH分别为7.5和8.0,最高质量浓度分别为22.5和60g/L.碳酸盐是影响产酸与有机酸分布的主要因素.比较ATCC 13870在NaHC03浓度为40和400mmol/L时的代谢通量,发现后者合成琥珀酸的代谢通量比前者提高了214.1%,合成乳酸的代谢通量降低了61.8%,说明PEP节点处的代谢通量分配明显受NaHCO3浓度的影响,而PYR节点受环境因素的影响不明显.     

Reactive extraction of lactic acid using alamine 336 in MIBK: equilibria and kinetics

Lactic acid is an important commercial product and extracting it out of aqueous solution is a growing requirement in fermentation based industries and recovery from waste streams. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid-amine (solvent) system used. Equilibria for lactic acid extraction by alamine 336 in methyl-iso-butyl-ketone (MIBK) as a diluent have been determined. The extent to which the organic phase (amine +MIBK) may be loaded with lactic acid is expressed as a loading ratio, z=[HL](o)/[B](i,o). Calculations based on the stoichiometry of the reactive extraction and the equilibria involved indicated that more lactic acid is transferred to the organic phase than would be expected from the (1:1) stoichiometry of the reaction. The extraction equilibrium was interpreted as a result of consecutive formation of two acid-amine species with stoichiometries of 1:1 and 2:1. Equilibrium complexation constant for (1:1) and (2:1) has been estimated. Kinetics of extraction of lactic acid by alamine 336 in MIBK has also been determined. In a first study of its kind, the theory of extraction accompanied by a chemical reaction has been used to obtain the kinetics of extraction of lactic acid by alamine 336 in MIBK. The reaction between lactic acid and alamine 336 in MIBK in a stirred cell falls in Regime 3, extraction accompanied by a fast chemical reaction occurring in the diffusion film. The reaction has been found to be zero order in alamine 336 and first order in lactic acid with a rate constant of 1.38 s(-1). These data will be useful in the design of extraction processes.     

响应面优化产琥珀酸放线杆菌生产丁二酸

丁二酸是一种重要的C4化合物平台,可以合成一系列重要化合物。文中对产琥珀酸放线杆菌Actinobacillus succinogenes GXAS137发酵生产丁二酸培养基成分进行优化。通过单因素和Plackett-Burman试验设计筛选出影响丁二酸发酵的重要参数,采用最陡爬坡实验逼近最大丁二酸生产区域后,利用Box-Behnken设计确定重要参数的最佳水平。筛选结果表明,影响丁二酸产量的重要参数是葡萄糖、酵母提取物和碱式碳酸镁浓度。最佳条件为(g/L)：葡萄糖70.00,酵母提取物9.20,碱式碳酸镁58.10。优化后丁二酸产量达到47.64 g/L。与初始条件 (36.89 g/L) 相比,丁二酸浓度提高了30 %。在最佳工艺条件下得到的试验结果与模型预测值很吻合,说明建立的模型是有效的。     

Investigations of biocompatible systems for reactive extraction of propionic acid using aminic extractants (TOA and Aliquat 336)

This paper presents the reactive extraction of propionic acid from aqueous solution by amine based extractants such as tri-n-octylamine and Aliquat 336, dissolved in a mixture of n-dodecane and 1-decanol. Equilibrium experiments were carried out to investigate the effects of various parameters such as modifier (1-decanol) concentration, extractant type, extractant composition, diluent composition, and initial acid concentration on the extraction efficiency. The extraction efficiency was found to be increased with an increase in modifier composition and extractant composition, and decreased with increases in initial acid concentration. Different biocompatible extractant/diluent systems such as (1) 20% TOA, 20% 1-decanol and 60% n-dodecane, (2) 20% TOA, 30% 1-decanol and 50% n-dodecane, (3) 30% TOA, 20% 1-decanol and 50% n-dodecane and (4) 25% Aliquat 336, 25% 1-decanol and 50% n-dodecane are developed and used in this study. A mathematical model based on mass action law and a population-based search algorithm (differential evolution, DE) is proposed, and is used to estimate the extraction equilibrium constant (K _E) and stoichiometry of reactive extraction. Individual equilibrium constants for the simultaneous formation of (1:1) and (2:1) acid:amine complexes are also determined. The extraction system comprised of 20% TOA, 30% 1-decanol, and 50% n-dodecane was found to be the best among the four biocompatible extractant/diluent systems studied. The loading ratios found in the range of 0.113 ～ 1.05 indicated the simultaneous formation of 1:1 and 2:1 complexes between acid and TOA.     

产琥珀酸重组解脂酵母发酵副产物乙酸的代谢控制

琥珀酸是一种高附加值的有机酸,广泛用于食品、化工和农药领域。解脂酵母Yarrowia lipolytica作为新型强健的非传统酵母,近年来逐渐吸引了研究者的注意。前期通过基因敲除琥珀酸脱氢酶基因构建了一株产琥珀酸的重组解脂酵母PGC01003。由于糖酵解和TCA循环流量不协调,PGC01003分泌大量副产物乙酸,限制了琥珀酸产量的进一步提高。为降低乙酸的溢出,实现自然低pH值发酵生产琥珀酸,首先干扰旁路代谢,异源表达来自鼠沙门氏菌的乙酰辅酶A合酶,乙酸的产量下降至4.6 g/L,比对照降低了24.6%。而基因敲除乙酰辅酶A水解酶基因得到的重组菌PGC11505,发酵96 h乙酸分泌量只有0.4 g/L,琥珀酸产量提高到7.0 g/L,琥珀酸的转化率为0.30 g/g,为进一步构建高产琥珀酸的细胞工厂奠定基础。     

Succinic Semialdehyde as a Substrate for the Formation of γ-Aminobutyric Acid

The conversion of succinic semialdehyde into gamma-aminobutyric acid (GABA) by GABA-transaminase was measured in rat brain homogenate in the presence of different concentrations of the cosubstrate glutamate. The calculated kinetic parameters of succinic semialdehyde for GABA-transaminase were a limiting Km value of 168 microM and a limiting Vmax value of 38 mumol g-1 h-1. Combination with previously obtained data for the conversion of GABA into succinic semialdehyde revealed a kEq value of 0.04, indicating that equilibrium of GABA-transaminase is biased toward the formation of GABA. The increased formation of GABA in the presence of succinic semialdehyde was not due to an increased conversion of glutamate into GABA by glutamic acid decarboxylase. Therefore these results indicate that succinic semialdehyde can act as a precursor for GABA synthesis.     

利用嗜盐菌Salinivibrio YS生产2,3-丁二醇和琥珀酸

以从新疆艾丁湖采集的土样中分离出的中度嗜盐菌Salinivibrio YS为研究对象,利用该菌在厌氧条件下生产2,3-丁二醇和琥珀酸,在单因素摇瓶实验基础上,确定影响产物积累的各因素及其相应条件,再利用正交试验确定这些参数的最佳水平,即温度33℃,起始pH为8.0,发酵过程pH为7.0,乙酸添加量为3 g/L,NaCl浓度为l0 g/L.利用优化条件进行3L体系的发酵放大实验,经过108 h的无氧发酵,2,3-丁二醇的产量可达35.05 g/L,而琥珀酸的含量则高达22.46 g/L,且其糖的总转化率高达约50％.首次利用嗜盐菌在厌氧条件下生产2,3-丁二醇和琥珀酸,拓展了嗜盐菌的应用,同时也为生产2,3-丁二醇和琥珀酸提供了新的思路.