Separation Of Lactic Acid Research Articles

Modeling and optimization of adsorption behavior of lactic acid onto zirconium-based metal-organic framework: response surface methodology (RSM)

ABSTRACT Lactic acid is readily generated in bacterial fermentations; however, a significant amount of processing and expenses are required for the purification of lactic acid in the fermentation broth. In this work, the sorption of lactic acid from a simulated broth has been studied by utilizing zirconium-based metal-organic framework (Zr-UiO-66 MOF) that acts as a prominent adsorbent due to its specific geometries and functional groups. The morphological, and structural properties of the prepared MOF are investigated using different characterization techniques such as Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) analysis, and Brunauer-Emmett-Teller (BET) analysis. The characterization results demonstrate the accuracy of the synthesis procedure. In order to achieve an efficient lactic acid separation process, it is essential to determine the optimal operational conditions. To address this, response surface methodology (RSM) was employed to devise an approach for optimizing five crucial process parameters for achieving the optimal response in lactic acid recovery removal. These parameters include initial LA concentration (ranging from 1 to 36 mg.L−1), pH (3–10), temperature (25 to 55 °C), adsorbent mass (0.25 to 1 g), and contact time (10 to 240 min). The RSM analysis revealed that the quadratic model provided the best fit for the experimental data, with a high coefficient of determination (R2). Three validation trials were carried out to determine the precision of the optimization process, leading to a maximum adsorption efficiency of 97.7% being reached under the optimized conditions (initial concentration = 18.5 mg.L−1, pH = 6.5, adsorbent mass = 0.625 g, contact time = 240 min, and temperature = 40 °C).

In-situ formation of hydrophobic deep eutectic solvents to separate lactic acid: Lactam as hydrogen bond acceptor and lactic acid as hydrogen bond donor

Lactic acid (LA) is a typical high added-value chemical and platform molecule derived from renewable biomass. To realize high efficiency and green separation of LA is of both scientific and practical significance. In this work, we proposed a novel mechanism of in-situ formation of hydrophobic deep eutectic solvents (HDES) to couple the separation of LA and synthesis of HDES. Due to the high solubility of LA as hydrogen bond donor in water, three hydrophobic lactams (N-Octyl-2-pyrrolidone (NOP), N-Dodecyl-2-pyrrolidone (NDP) and 2-Octyl-4-isothiazolin-3-one (OIT)) were optioned as hydrogen bond acceptors. The effect of lactam molecular structure on separation efficiency was discussed and compared in detail. The compositions of HDES forming in-situ were found to be 1.50 for NOP and NDP to LA while 1.20 for OIT to LA using experiments of slope method and continuous variations method. The key evidence of formation of HDES was confirmed by FT-IR, frontier molecular orbital analysis and interaction region indicator analysis. The multistage counter-current extraction experiment results showed the in-situ formation of HDESs can transfer 99% of LA from fermentation broth to the HDES, and LA was separated completely from the impurities. This work provided a new perspective on lactic acid separation and its potential industrial applications.

Determination of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat by ultrahigh-performance liquid chromatography-tandem mass spectrometry.

Succinic acid and lactic acid have been associated with diarrhea in weaned piglets. The level of succinic acid and lactic acid in serum, meat, and intestinal contents is important to elucidate the mechanism of diarrhea in weaned piglets. A facile method was developed for the quantification of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS). The serum samples underwent protein precipitation with methanol. The meat and intestinal contents were freeze-dried and homogenized using a tissue grinding apparatus. Methanol-water mixture (80:20, v/v) was used for homogenizing the meat, while water was used for homogenizing the intestinal contents. An additional step of protein precipitation with acetonitrile was required for the intestinal contents. The resulting solution was diluted with water before being analyzed by UHPLC/MS/MS. Separation of succinic acid and lactic acid could be achieved within 3min using a Kinetic XB-C18 column. The coefficients of variation for peak areas of succinic acid and lactic acid were less than 5.0%. The established method demonstrated good linearity as indicated by correlation coefficients exceeding 0.996. Additionally, satisfactory recoveries ranging from 88.58% to 108.8% were obtained. The detection limits (RS/N = 3) for succinic acid and lactic acid were determined to be 0.75 ng/mL and 0.02 μg/mL, respectively. This method exhibited high sensitivity, simplicity in operation, and small sample weight, making it suitable for quantitative determination of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat. The method developed will provide valuable technical support in studying the metabolic mechanisms of succinic acid and lactic acid in pigs.

Development of a hybrid bio-purification process of lactic acid solutions employing an engineered E. coli strain in a membrane bioreactor

BackgroundA potential alternative to lactic acid production through sugar fermentation is its recovery from grass silage leachate. The separation and purification of lactic acid from fermentation broths remain a key issue, as it amounts to up to 80% of its industrial production cost. In this study, a genetically engineered E. coli strain (A1:ldhA), that cannot catabolize lactic acid, has been used to selectively remove impurities from a synthetic medium comprising typical components (i.e., glucose and acetic acid) of green grass silage leachate. A systematic approach has been followed to provide a proof-of-concept for a bio-purification process of lactic acid solutions in a membrane bioreactor operating in semi-continuous mode.ResultsThe synthetic medium composition was initially optimized in shake-flasks experiments, followed by scale-up in bench-scale bioreactor. Complete (i.e., 100%) and 60.4% removal for glucose and acetic acid, respectively, has been achieved in batch bioreactor experiments with a synthetic medium comprising 0.5 g/L glucose and 0.5 g/L acetic acid as carbon sources, and 10 g/L lactic acid; no lactic acid catabolism was observed in all batch fermentation tests. Afterwards, a hybrid biotechnological process combining semi-continuous bioreactor fermentation and ultrafiltration membrane separation (membrane bioreactor) was applied to in-situ separate purified medium from the active cells. The process was assessed under different semi-continuous operating conditions, resulting in a bacteria-free effluent and 100% glucose and acetic acid depletion, with no lactic acid catabolism, thus increasing the purity of the synthetic lactic acid solution.ConclusionsThe study clearly demonstrated that a bio-purification process for lactic acid employing the engineered E. coli strain cultivated in a membrane bioreactor is a technically feasible concept, paving the way for further technological advancement.

Separation of Lactic Acid and Acetic Acid through Supported Ionic Liquid Membranes Containing Cyphos IL 101

Separation of Lactic Acid and Acetic Acid through Supported Ionic Liquid Membranes Containing Cyphos IL 101

Separation of lactic acid from fermented residual resources using membrane technology

Lactic acid can be derived from microbial fermentation and be used as a platform chemical in various industrial applications. This study aims to investigate the challenges involved in combining a low-cost, heterogeneous feedstock, such as a mixture of candy-waste and digestate, with an optimized downstream strategy to achieve maximum recovery of high-purity lactic acid, targeting low energy consumption. To achieve this goal, four membrane separation technologies, namely microfiltration, nanofiltration, monopolar, and bipolar electrodialysis, were combined to design two purification processes. Microfiltration served as the pre-purification step, followed by either process A, which combined nanofiltration and bipolar electrodialysis, or process B, a combination of monopolar and bipolar electrodialysis. The findings emphasized the importance of pH as a control factor. Nanofiltration at pH 2.8 and monopolar electrodialysis at pH 4.0 led to increased lactic acid recovery. Moreover, it was observed that process B resulted in 1.09-fold higher lactic acid recovery than process A. However, process A had a 1.19-fold lower specific energy consumption, and the presence of ions in the final solution was reduced by 5-fold. In both processes lactic acid was separated from sugars and organic acids. Overall, the findings of this study suggest that membrane separation technology is a viable method for separating lactic acid produced from a mixture of residual candy-waste and digestate.

Modeling of lactic acid rejection from lactose in acidified cheese whey by nanofiltration

The continuously increasing demand of lactic acid opens a window for the integration of membrane technology in the dairy industry, improving the sustainability by avoiding the use of large amounts of chemicals and waste generation. Lactic acid recovery from fermentation broth without precipitation has been studied by numerous processes. In this work, a commercial membrane with high lactose rejection and a moderate lactic acid rejection, enabling a permselectivity up to 40%, is sought to perform the simultaneous removal of lactic acid and lactose separation from the acidified sweet whey from mozzarella cheese production in a single stage. The AFC30 membrane of the thin film composite nanofiltration (NF) type was selected because of its high negative charge, low isoelectric point, and divalent ion rejection, as well as a lactose rejection higher than 98% and a lactic acid rejection lower than 37%, at pH 3.5, to minimize the need of additional separation steps. The experimental lactic acid rejection was evaluated at varying feed concentration, pressure, temperature, and flow rate. As the dissociation degree of lactic acid is negligible in industrially simulated conditions, the performance of this NF membrane was validated by the irreversible thermodynamic Kedem-Katchalsky and Spiegler-Kedem models, with the best prediction in the latter case, with the parameter values: Lp = 3.24 ± 0.87 L × m-2 × h-1 × bar-1 and = 15.06 ± 3.17 L × m-2 × h-1, and σ = 0.45 ± 0.03. The results obtained in this work open the way for the up-scaling of membrane technology on the valorization of dairy effluents by simplifying the operation process and the model prediction and the choice of the membrane.

An integrated biorefinery approach to obtain xylo-oligosaccharides from corncob using lactic acid-rich fermentation broth

Although xylo-oligosaccharides production from lignocelluloses via lactic acid hydrolysis is advantageous in terms of high yields with less by-products, the use of high purity lactic acid inevitably increases the cost of xylo-oligosaccharides production. The utilization of lactic acid-rich fermentation broth for xylo-oligosaccharides production can avoid the separation and purification of lactic acid. However, the feasibility of lactic acid-rich fermentation broth for xylo-oligosaccharides production from lignocelluloses was unclear. In this work, the results indicated that the highest xylo-oligosaccharides yield of 72% was obtained from corncob by lactic acid-rich fermentation broth pretreatment and xylanase hydrolysis. Subsequently, monosaccharides-rich hydrolysate (90.9 g/L) was obtained from solid residues of corncob by cellulase hydrolysis. Lactic acid-rich fermentation broth was produced by Weizmannia coagulans fermentation of the monosaccharide-rich hydrolysate. Besides, the obtained xylo-oligosaccharides and lactic acid mixture might be used as feed additives, avoiding the purification and separation of lactic acid or xylo-oligosaccharides. Meanwhile, the production cost of feed grade xylo-oligosaccharides from this work was much lower than the current market price. Overall, this work proposed a new strategy for efficient and environmental-friendly production of xylo-oligosaccharides from corncob.

Reactive Extraction of Lactic Acid Using Trioctylamine with Environmentally Friendly Solvents

In this study, the separation of lactic acid from aqueous solutions using trioctylamine (TOA) reactant and environmentally friendly solvents such as sunflower and rice bran oil was investigated, and it was aimed to contribute to the separation of lactic acid by reactive extraction. It is aimed to determine the most suitable reactant / solvent ratios with reactive extraction analyzes. As a result of the studies, the highest efficiency (72,91%) was achieved with the TOA reactant. An increase in yield occurred as a result of using both sunflower oil and rice bran oil (1:1) together. According to the results of the research, it was determined that the addition of TOA to the organic phase increases the extraction efficiency in the recovery of carboxylic acids from aqueous solutions. While the physical extraction yield was 11.85%, the yield increased up to 72,91% in reactive extraction. An increase in yield was observed about 7 times. As a result of the data obtained, it was understood that with the increase in the extractant concentration, the dispersion coefficient (from 0,13 to 2,69) increased, and the loading factor (from 1,79 to 0,69) values decreased. When the organic phase mixtures formed with the extractant and diluent combinations were examined, it was determined that the best results in terms of extraction efficiency were obtained when 3,62 M TOA for lactic acid was used.

Comparative study of liquid–liquid equilibria for aqueous mixtures of lactic acid with structurally similar cyclic and non-cyclic ketones

Liquid-liquid equilibria (LLE) were studied and compared for the aqueous mixtures of lactic acid (L(+) enantiomer) with the two structurally similar α,β-unsaturated ketones (mesityl oxide or isophorone)} at 298.2, 308.2, and 318.2 K and 101.3 kPa. Due to the close structural similarity of the chosen solvents, an experimental and correlational study was systematically carried out on performance of mesityl oxide and isophorone to extract l-lactic acid from water. The ternary systems exhibit type-1 behavior of LLE. The thermodynamic models of NRTL and UNIQUAC were successfully applied to fit the experimental tie-lines and the model binary interaction parameters were determined. The consistency of the calculated NRTL parameters was validated and qualified through topological analysis connected to the Gibbs tangent principle and stability test. Evaluation of the capacity of each solvent was performed using the calculation of distribution coefficients and separation factors. The influence of extraction temperature and the chemical structure of the solvent on the immiscibility region were found to be small. As a result, the selectivities specify that both the cyclic and non-cyclic ketones were found to be promising extractants for the separation of lactic acid from its dilute aqueous solutions.

Separation of Lactic Acid Based on Amide-Based Hydrophobic Deep Eutectic Solvents: Insights from Experiments and Molecular Dynamics Simulations

Separation of Lactic Acid Based on Amide-Based Hydrophobic Deep Eutectic Solvents: Insights from Experiments and Molecular Dynamics Simulations

Separation of lactic acid and by-products obtained by catalytic conversion of glycerol using high-performance liquid chromatography

Lactic acid is an attractive raw material in synthesizing many products. A new method for quantifying glycerol, lactic acid, and the by-products (pyruvaldehyde) obtained in this reaction was developed using high-performance liquid chromatography (HPLC) with a refractive index detector (HPLC-RI) in a column (300 � 7.7 mm, 8 �m) using H2SO4 0.001 M + 10% ACN (organic modifier) as mobile phase (0.6 mL min�1). This method indicated outstanding linearity for glycerol and lactic acid concentration from 0.6 to 6.6 g L�1 (coefficient of determination (R�) = 0.9912 and 0.9961, respectively) and accuracy between 98.33 and 100.00%. From this, it was possible to conclude that the method is applicable and concise for separating the primordial products in this reaction.

Ion-Exchange Technology for Lactic Acid Recovery in Downstream Processing: Equilibrium and Kinetic Parameters

The downstream processing for the separation and purification of lactic acid is a hot research area in the bio-refinery field due to its continuous growing market in different sectors, such as the food, cosmetic and pharmaceutical sectors. In this work, the use of ion-exchange technology for lactic acid recovery is proposed. For that, four anion exchange resins with different polymer structures and functional groups were tested (A100, MN100, A200E and MP64). The sorption process was optimized by the Box–Behnken factorial design, and the experimental data obtained in the sorption process were analyzed by using the response surface methodology and fitted at different isotherms and kinetics models. Moreover, regenerant type, contact time and solid/liquid ratio were evaluated in the desorption process. Results showed that the best resin for lactic acid removal was A100, at pH = 4, with a resin/lactic acid solution ratio of 0.15 g/mL during a maximum of 1 h, achieving 85% of lactic acid removal. Moreover, equilibrium data sorption of lactic acid onto A100 resin was fitted by a Langmuir isotherm and by a kinetic model of a pseudo-second order. In addition, in the desorption process, it was stablished that a resin/regenerant ratio of 0.15 g/mL during 30 min with 0.1 M of NaOH solution provided the best results (4.45 ± 0.08 mg/g).

Investigation of the effects of ionic liquid as diluent in separation of lactic acid from aqueous media by reactive extraction

The fact that fossil fuels will be depleted in near future and the increase of environmental awareness in humans causes biotechnology to seek new and develop existing processes constantly. That is why researchers have turned to work in this field in recent years. In this study, the separation of lactic acid, an industrially important organic acid, from aqueous solutions by reactive extraction method where tripropylamine (TPA) has been used as an extractant and hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) as a diluent was investigated. Six different traditional organic solvents (n-pentane, toluene, 2-octanone 1-octanol, methyl isobutyl ketone (MIBK), dimethyl phthalate (DMP)) have been chosen to compare the efficiency of the selected ionic liquid. The batch physical and reactive extraction experiment results were presented as distribution coefficient (D), loading factor (Z), and extraction efficiency (E). All experiments were performed at 298.15 K with an initial lactic acid concentration of 1.28 mol·L-1 (10.275% w/w). In reactive extraction experiments, the effect of different TPA concentrations (0.35–1.4 mol·L-1) on extraction efficiency was investigated. While the extraction efficiency in physical extraction varied between 5.55 and 14.06%, ionic liquid has the highest extraction efficiency. In the reactive extraction results, it was seen that the ionic liquid has 99.61% extraction efficiency at 1.40 mol·L-1 TPA concentration. According to this result, the use of (TPA + 1-butyl-3-methylimidazolium hexafluorophosphate) organic mixtures is a suitable alternative to separate lactic acid from aqueous solutions.

Conceptual design of a dual reactive dividing wall column for downstream processing of lactic acid

Methodologies for designing intensified processing units are necessary to enable the industrial application of process intensification concepts. This article presents a ruled-based systematic methodology for the synthesis and conceptual design of a dual reactive dividing wall column (dual R-DWC). A decomposition approach is used to identify the tasks required for the separation by introducing a reactive separating agent to exploit a reversible reaction to enhance the driving forces. A combination of shortcut and rigorous simulations led to the conceptual design of a novel dual R-DWC in which the forward and reverse reactions and the separation occur at once.The methodology was demonstrated in a case study for the separation of lactic acid from dilute aqueous streams and a reactive impurity that hinders the lactic acid conversion and its recovery, while the byproducts may bring new challenges for the desired separations.This study is the first to investigate the effect of reactive impurities on the reaction and the separation, hence adding a more realistic framework to the design. The flowsheet produced was evaluated against benchmark processes and showed a significant process improvement in terms of energy savings (ranging 13-27 %), material intensity (28-32 % reduction), and water consumption (22-36 % reduction), while the reactive impurities are effectively removed.

Lactic Acid and Salt Separation Using Membrane Technology.

Acid whey is a by-product of cheese and yoghurt manufacture. The protein and lactose within acid whey can be recovered using nanofiltration and electrodialysis, but this leaves a waste stream that is a mixture of salts and lactic acid. To further add value to the acid whey treatment process, the possibility of recovering this lactic acid was investigated using either low energy reverse osmosis membranes or an electrodialysis process. Partial separation between lactic acid and potassium chloride was achieved at low applied pressures and feed pH in the reverse osmosis process, as a greater permeation of potassium chloride was observed under these conditions. Furthermore, lactic acid retention was enhanced by operating at lower temperature. Partial separation between lactic acid and potassium chloride was also achieved in the electrodialysis process. However, the observed losses in lactic acid increased with the addition of sodium chloride to the feed solution. This indicates that the separation becomes more challenging as the complexity of the feed solution increases. Neither process was able to achieve sufficient separation to avoid the use of further purification processes.

Stationary phase type and temperature effect on HPLC separation of lactic acid enantiomers

Abstract Lactic acid is a biologically important organic acid existing in two enantiomeric forms which are differently metabolized in the human body. In this paper, direct chiral separation of lactic acid by high performance liquid chromatography is presented. Five chiral stationary phases based on macrocyclic antibiotics were used for enantioseparation and chromatographic parameters, such as retention factors, resolution and selectivity factors, were determined under different column temperatures ranging from 5 to 45 °C. Optical isomers of lactic acid were efficiently separated using chiral stationary phases based on teicoplanin (R S = 1.9 ) and ristocetin (R S = 1.7 ) in reversed-phase separation mode at the column temperature of 25 °C.

Lactic Acid Permeation through Deep Eutectic Solvents-Based Polymer Inclusion Membranes.

Lactic acid that is prepared by fermentation is a compound in food, cosmetic pharmaceutical, and chemical industries. Since a simple technique is desired that separates lactic acid from the cultures, we propose lactic acid permeation through a poly(vinyl chloride)(PVC)-based membrane that contains deep eutectic solvents (DESs) as a carrier. Lactic acid was successfully permeated through polymer inclusion membranes (PIMs) containing hydrophilic DESs, urea-choline chloride and glucose-choline chloride. The permeation behavior was explained by the facilitated transport mechanism based on the solution-diffusion model. Simple preparation of thinner membranes in the PIM process and higher permeation rates are advantages over the supported liquid membrane process. The PVC-based membrane process containing environmentally benign hydrophilic DESs is promising for lactic acid separation on an industrial scale.

Development of Polyaniline Based Anion Exchange Membrane for the Separation of Lactic Acid via Electrodialysis

Nowadays, industrial waste from feedstock contains a lot of organic acids, which are being discharged into the water streams causing environment load with wastage of resources. Electrodialysis performs an important role in wastewater treatment. In this study, we have prepared different anion exchange membranes, by casting solution of poly(vinylchloride-co-vinylacetate) (PVC–VA) with uniformly dispersed micronized anion exchange resin (polystyrene–divinylbenzene–trimethyl ammonium chloride) (PS–DVB–TAC). These membranes were also processed for the deposition of polyaniline at different time intervals by in situ polymerization. The cation exchange membrane (CEM) was also produced by casting a solution, containing (PVC–VA) with micronized cation exchange resin [sulfonated poly(styrene-co-divinylbenzene)] (SPS–DVB). The separation of the model solution of lactic acid was performed by using anion exchange membrane (with coated/without coated PANI) and cation exchange membranes (CEM) in a four-compartment electrodialyzer at same voltage. These different modified forms of anion exchange membranes were characterized by FTIR/ATR for identification of functionalities within the polymer chain, SEM analysis for surface morphology, TGA for thermal stability and a four-probe method for electrical conductivity of membranes. While, % age of water uptake and ion exchange capacity were also determined. The results of electrodialysis showed that the 14.78% of the lactate ions moved through anion exchange membrane (without a coating of PANI) to the product compartment within 30 min of the experiment at (30 V). While, the membranes with polyaniline’s coating time 2, 12, and 24 h have separation efficiency of lactic acid 21.65, 27.46, and 33.36% respectively at the same voltage. The results clearly showed that higher PANI coating has a positive trend in the separation of lactic acid. This separation technique has a great potential in the separation of organic acids and amino acids from a feedstock of microbial fermentation at an industrial scale.

A study of the residual fermentation sugars influence on an alternative downstream process for first and second-generation lactic acid

Lactic acid is an important biomolecule with a substantial market share. Currently, investments in the area are concentrated on new substrates and technologies, in order to boost production and separation performance. Molecular distillation has been recognized as a promising technology in the separation, purification, and concentration of natural products and hence with potential for application in the lactic acid production process. In this study, lactic acid was produced by fermentation using first (1G) and second-generation (2G) substrates, producing a complex mixture of lactic acid and residual sugars. The influence of the residual sugars, such as glucose, sucrose, and xylose, was investigated. For the 1G process, the results showed that the highest lactic acid concentration (99.51 g/L) can be obtained using the feed stream with the lowest sugars composition. For the 2G process, the highest lactic acid concentration reached (75.87 g/L) was lower than that observed for 1G experiments. The concentration of lactic acid using 1G or 2G lactic acid were, respectively, 2.73 times and 2.12 times higher than the initial raw material concentration, without the use of any extra solvent. The final process analysis showed that the use of molecular distillation for lactic acid downstream has different challenges to defeat for the separation of 1G and 2G lactic acid, which is relevant since many different feedstocks may be used in the lactic acid production.