Use Of Lactic Acid Research Articles

Use of green solvents as pre-treatment of dissolving pulp to decrease CS2 consumption from viscose production

Choline chloride-based deep eutectic solvents are widely used in biomass processing. In this work, four different green solvent mixtures were used as pre-treatment of acid sulphite dissolving pulp with the hypothesis of increasing the possibilities to produce viscose fibres and decreasing the use of the harmful and toxic carbon disulphide in the process. The experiments were performed at two different pulp to solvent mass ratios. Pulp quality parameters were also measured to determine the suitability of the pre-treatment: α-cellulose, viscosity, lignin and pentosan content. In addition, X-ray diffraction analysis of pulps at the best solid to liquid ratio was performed to obtain the influence of the crystallinity index. Best results were obtained with the use of lactic acid, with reactivity values close to 94%, giving a reduction of CS2 usage of 15.83%. Furthermore, a linear relationship between the crystallinity index calculated by the XRD and reactivity with a regression factor of 0.87 was found.

A heterogeneous microbial consortium producing short-chain fatty acids from lignocellulose.

Microbial consortia are a promising alternative to monocultures of genetically modified microorganisms for complex biotransformations. We developed a versatile consortium-based strategy for the direct conversion of lignocellulose to short-chain fatty acids, which included the funneling of the lignocellulosic carbohydrates to lactate as a central intermediate in engineered food chains. A spatial niche enabled in situ cellulolytic enzyme production by an aerobic fungus next to facultative anaerobic lactic acid bacteria and the product-forming anaerobes. Clostridium tyrobutyricum, Veillonella criceti, or Megasphaera elsdenii were integrated into the lactate platform to produce 196 kilograms of butyric acid per metric ton of beechwood. The lactate platform demonstrates the benefits of mixed cultures, such as their modularity and their ability to convert complex substrates into valuable biochemicals.

Building niches for multiple microbes

Microbial Engineering Microbial conversion of heterogeneous feedstocks such as lignocellulose into one or more desired products requires assembly of pathways to both break down the inputs and produce the outputs. Shahab et al. assembled a collection of microbes that occupy different spatial niches within a bioreactor and have different metabolic capabilities. In the simplest version of their setup, an aerobic fungus adeptly breaks down cellulose into short sugar chains, an oxygen-tolerant bacterium converts these to lactic acid, and an anaerobic bacterium uses the lactic acid to synthesize the short-chain fatty acid butyric acid. Additional microbes handle limitations in the intermediate stream or divert lactic acid to longer-chain fatty acids, which are potentially more valuable. The integrated production and use of lactic acid for biosynthetic reactions could ideally serve as a platform for biosynthesis using robust, heterogeneous microbial consortia. Science , this issue p. [eabb1214][1] [1]: /lookup/doi/10.1126/science.abb1214

Simultaneous removal of Cr(III) from high contaminated soil and recovery of lactic acid from the spent solution

It is proposed a closed-loop treatment cycle for Cr(III) removal from contaminated soils (2080 mg/kg). The treatment includes the use of lactic acid as washing agent, and the recovery of both Cr(II) and lactic acid from the spent solution. Results indicate that Cr(III) removal efficiency can be very high, passing 70% in all tested operative conditions. The metal forms strong complexes with lactic acid, and therefore cannot be eliminated through direct precipitation simply increasing the pH value. Therefore, lactic acid is preliminarily extracted from the solution using n-butanol at very acidic pH. The obtained extraction degree is generally high, varying between 0.5 and 1 according to the amount of used n-butanol solution. After lactic acid extraction, almost 100% of chromium can be recovered through precipitation in alkaline conditions. Lactic acid, in turns, can be purified and reused for a new washing treatment, separating it from n-butanol solution through water extraction. The extraction efficiency is once more satisfying (around 0.5), and not dependent on the operative pH.

Effect of Lactic Acid on Inactivation of Enterotoxigenic Escherichia Coli (ETEC) Isolated from Tuna Loins Produced in Côte D’Ivoire

Aims: The aim of this work was to study the effect of lactic acid on the growth of pathogenic strains of Escherichia coli (ETEC) isolated from tuna loins.
 Study Design: Bacteriological study.
 Place and Duration of Study: Laboratory of Microbiology of the Central Laboratory of Food hygiene and Agrobusiness (LCHAI), Abidjan, Côte d’Ivoire between September 2014 and December 2014.
 Methodology: Enterotoxigenic Escherichia coli (ETEC) strains were isolated from tuna loins. Lactic acid (LA) 1%, 2% and 3% were tested in pathogenic strains in liquid medium (brain heart infusion broth, BHI) and in tuna loins.
 Results: At lactic acid 1%, the bacterial loads decreased during the first two days and then stabilized. E. coli strains in tuna loins were higher (1.25 to 0.9 log CFU/g) than E. coli in liquid medium (0.69 to 0.3 log CFU/g). No bacterial growth was observed in the tuna loins and in BHI for concentrations of 2% and 3% of lactic acid.
 Conclusion: Lactic acid has an inhibitory effect at 1% and bactericidal effect at 2% and 3% on the growth of E. coli. The use of lactic acid as a preservative could be a solution for the preservation of these products.

Study of the separation of didymium from lanthanum using liquid-liquid extraction: Comparison between saponification of the extractant and use of lactic acid

The liquid-liquid extraction (LLE) technique is widely used for industrial-scale separation of rare-earth elements (REEs). However, the low selectivity of LLE in separating REEs, mainly adjacent elements, has prompted the investigation of modifications of this technique to find new routes that are more efficient. The selectivity of REEs separation increases when saponified extractants are used. However, saponification generates effluents containing sodium or ammonium ions that need to be removed before discharge into water bodies or be reused. As an alternative to saponification, the conditioning of the feed liquor with complexing agents has been proposed. This study compares the efficiency of didymium (Pr + Nd) and lanthanum separation with saponified and non-saponified organophosphorus extractants and with addition of lactic acid to the feed liquor. The extractants investigated were D2EHPA, P507 and Cyanex 272. The effect on the didymium/lanthanum separation of initial pH, saponification degree and lactic acid concentration and extractant were evaluated. The La and didymium separation were better when the feed solution was conditioned with lactic acid than when the extractants D2EHPA and P507 were saponified. Conversely, La and didymium separation was better when Cyanex 272 was saponified than when the feed liquor was conditioned with lactic acid. These results indicate that conditioning the feed liquor with lactic acid has the potential to replace the practice of saponification of the extractants D2EHPA and P507.

Quality characteristics of horse meat as influence by the age of horse

ABSTRACT This study aimed at the analysis of the impact of the age of horses and selected substances (lactic acid, malic acid, salt phosphates, and phosphates with rosemary) on the quality of horse meat during cold storage. Samples of the longest thoracic muscle obtained from 12 half-carcasses of horses from two age groups: from 4 to 7 years and from 8 to 12 years constituted the research material for the analysis. The addition of each of the substances (lactic acid, malic acid, salt phosphates, phosphates with rosemary) used to marinate this meat increased the color brightness and reduced the value of shear force and hardness compared to the control sample (P < .05) in both age groups. The use of lactic acid for marinating in the case of meat from both younger and older horse carcasses affected the lowest sensory evaluation scores (P < .05) of this meat compared to the control sample and those for which other substances were used.

Bio‐Acrylates Production: Recent Catalytic Advances and Perspectives of the Use of Lactic Acid and Their Derivates

AbstractThe production of drop‐in chemicals from bio‐based renewable sources is gaining a lot of momentum due to proven negative impact of fossil‐based economy on environment and society. In this Review, various bio‐derived platform molecules are assessed as renewable alternatives to fossil resources for the catalytic production of acrylates. Acrylic acid and its esters are key building blocks of a large number of high‐value oligomers and polymers in the current industry. In spite of the encouraging successes reported on gram or lab‐scale, real implementation of bio‐based examples remain scarce mainly due to the current high cost and limited availability of the bio‐based substrates. As lactic acid and their derivatives are one of the most promising feedstocks for bio‐acrylate production, they are the main focus of this Review.

Lactic Acid as a Highly Efficient and Simplified Biocatalyst System for One-Step Synthesis of Multisubstituted Pyrroles

An acid-mediated three-component reaction for the synthesis of multisubstituted pyrroles has been developed from benzoin, C–H-activated compounds, and ammonium acetate/p-methoxy aniline. The advantage of this one-step metal-free approach is the use of lactic acid as a biodegradable, environmentally benign, and available catalyst and green solvent along with simple purification process involving no chromatographic process, high efficiency, short reaction time, and high yield of products.

Isolation of Lactic Acid Bacteria Eliminating Trimethylamine (TMA) for Application to Fishery Processing.

Fishy odor of fish flesh (meat) presents a severe problem for marine production. The main cause of fishy odor is trimethylamine (TMA), which increases during storage. It is produced from trimethylamine oxide (TMAO), an osmosis-regulating substance in fish cells that functions by a reduction reaction. Bacterial growth in fish meat increases TMA. Its odor reduces the commercial value of the meat. Technologies for its regulation and elimination are desired. This chapter presents a description of the use of lactic acid to eliminate TMA. The lactic acid is producible safely by bacteria during food processing using picric acid-toluene.A method of eliminating TMA was demonstrated using Lactobacillus plantarum H78. Furthermore, an assay method was explained for reducing TMA in fish meat by fermenting the H78 strain.

Use of lactic acid modified MoS2 nanopetals to improve photocatalytic degradation of organic pollutants

Transition metal dichalcogenide-based molybdenum disulfide (MoS2) are currently gaining considerable attention due to their prospective technological applications. Herein, we report a facile and simple one-step preparation of self-assembled two-dimensional MoS2 nanopetals modified with lactic acid (LA@MoS2). An investigation of the properties of the synthesized LA@MoS2 nanopetals under different conditions reveals that the weight percentage of lactic acid (LA) significantly influences the structural purity, crystalline quality, and morphology of the products, and the appropriate concentration of LA is the determining factor in the synthesis. Photocatalytic activity of LA@MoS2 nanopetals for organic dye decolorization is examined using crystal violet (CV) and methyl orange (MO). The results showed that LA molecules cover the MoS2 with C–S bonds, which significantly enhance photocatalytic decolorization of CV and MO pollutants under simulated solar light irradiation. The LA@MoS2 demonstrated excellent photocatalytic performance compared to bulk MoS2. Furthermore, electrochemical studies reveal fast electron and hole pathways for the reduction of pollutant molecules in aqueous solution. These results indicate that LA@MoS2 is a good photocatalyst because of the desirable active species in the modified catalyst.

The impact of Clostridium butyricum MIYAIRI 588 on the murine gut microbiome and colonic tissue

BackgroundClostridium butyricum MIYAIRI 588 (CBM 588) is a probiotic bacterium that is used as an anti-diarrheal medicine in Japan. However, the impact of this probiotic on the gut microbiome has not been fully elucidated, especially, when used with antimicrobials. Material and methodsIn an in vivo study, CBM 588 monotherapy, clindamycin monotherapy, CBM 588 and clindamycin (combination therapy), or normal saline (control) was orally administered to mice for 4 days, and fecal samples were collected for 18 days to enumerate C. butyricum. We also extracted DNA from these fecal samples for metagenomics analysis by amplification of the V3-V4 region of the bacterial 16S rRNA gene and MiSeq Illumina sequencing. In addition, the concentrations of some short chain fatty acids were assessed in the fecal samples. A histological analysis was also conducted. ResultsOn day 4 (the last treatment day), there was no difference in the total counts of C. butyricum between the CBM 588 monotherapy and combination therapy groups (5.21 ± 0.78 vs. 5.13 ± 0.45 log10 cfu/g, p = 0.86). Clindamycin treatment resulted in dramatic increases in the phylum Firmicutes, especially Enterobacteriaceae, Clostridiaceae, Lactobacillus, and Enterococcus, compared with the other groups during the treatment period. CBM 588 treatment modified the bacterial community composition at lower phylogenetic levels. Some bacterial taxa, such as Bifidobacterium, Coprococcus, and Bacteroides, were significantly increased in the combination therapy group when compared with the other groups. In the metabolic analysis, CBM 588 enhanced lactic acid production. It also enhanced the efficiency of lactic acid use for the production of butyric acid. Only the clindamycin monotherapy group showed abnormal colon tissue, with superficial epithelial necrosis and the presence of inflammatory cells. ConclusionCBM 588 treatment modulated the gut microbiota composition under dysbiosis due to the use of an antimicrobial with strong activity against anaerobes and significantly reduced epithelial damage.

Solvent extraction and separation of light rare earth elements (La, Pr and Nd) in the presence of lactic acid as a complexing agent by Cyanex 272 in kerosene and the effect of citric acid, acetic acid and Titriplex III as auxiliary agents

At present, the use of rare earth elements (REEs) has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La(III), Pr(III), and Nd(III) from an HCl medium with Cyanex 272 in the presence of the complexing agent lactic acid (HLac) and auxiliary agents citric acid (H3Cit), acetic acid (HAc), and Titriplex III have been reported. The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex III reduces the extraction percentage of LREEs. Finally, the presence of Titriplex III together with lactic acid could lead to an increase in the separation factor of Pr and Nd.

Influence of lactic acid on the catalytic performance of MDABCO for ring-opening polymerization of l-lactide

A series of metal organic frameworks (MOFs) MDABCO (M=Co, Ni, Cu, Zn; DABCO=1,4-diazabicyclo[2.2.2]octane) are utilized as catalysts for the bulk ring-opening polymerization of l-lactide. The catalytic activity varies in the order CuDABCO, NiDABCO<ZnDABCO, CoDABCO. By adding lactic acid, we unexpectedly observed enhanced catalytic activity. The combined use of lactic acid and ZnDABCO during polymerization results in a highly active polymerization system, along with the gradual change of MOFs structure caused by an increased acid concentration. Compared to related homogeneous fragments, such as zinc nitrate and 1,4-diazabicyclo[2.2.2]octane, ZnDABCO is found to afford highly isotactic polylactide, which would be ascribed to the unique structural properties of MOFs.

The role of lactic acid production by probiotic Lactobacillus species in vaginal health

Vaginal eubiosis is characterised by beneficial lactobacillus-dominated microbiota. In contrast, vaginal dysbiosis (e.g. bacterial vaginosis, BV), characterised by an overgrowth of multiple anaerobes, is associated with an increased risk of adverse urogenital and reproductive health outcomes. A major distinguishing feature between the vaginal environment in states of eubiosis and dysbiosis is a high concentration of lactic acid, produced by lactobacilli, that acidifies the vagina in eubiosis versus a sharp drop in lactic acid and an increase in pH in dysbiosis. Here we review the antimicrobial, antiviral and immunomodulatory properties of lactic acid and the use of lactic acid and lactobacilli probiotics in preventing or treating BV.

Chitosan/oxidized pectin/PVA blend film: mechanical and biological properties

This paper describes the preparation and characterization of flexible crosslinked chitosan (CH)/poly(vinyl alcohol) (PVA) films. These chitosan-based films are prepared using oxidized pectin as crosslinking agent, and PVA as plasticizer. The chemical structure of the obtained blend films were investigated using FTIR spectroscopy. Swelling behavior of hydrogels obtained was studied in various pH media. The blending of PVA with chitosan or chitosan/oxidized pectin (OP) was found to highly enhance the swelling of the prepared films compared to those obtained from pure chitosan. On the other hand, the use of lactic acid as solvent and the incorporation of PVA improve the flexibility of chitosan matrices. Examination of the hemolytic potential showed that the hydrogels were non hemolytic in nature. The hydrogels were non-toxic and blood-compatible. Reducing power was used to determine in vitro antioxidant activity and anti-inflammatory activity of chitosan films was investigated by protein denaturation method. The biological activity of CH/OP/PVA towards Pseudomonas aeruginosa, Staphylococus aureus, Bacillus subtilis and Escherichia coli has been examined in this study.

English

The aim of the research was to study the effect of adjusting the initial pH of shrimp shell (8.64 vs. 7.00) on the ability of the fungus Aspergillus niger to carry out deproteinization process of galactose supplemented shrimp shells and to investigate the performance characteristics of the deproteinization process. The results showed that the initial pH of the shells has a significant effect on the temperature, carbon dioxide emission, moisture content, galactose, proteinase activity, protein, chitin and final appearance of shells. The temperatures of the shrimp shells and the exhaust gas declined during the lag period as the heat losses from the bioreactor were higher than the heat generated by microbial activities in the bioreactor. They started to rise during the exponential growth when the heat generation by metabolic activity exceeded the heat losses, reaching maximum values of 37.5 and 30.6°C after 60 h and of 29.1 and 27.2°C after 72 h for the runs with the initial pH of 8.64 and 7.0, respectively. The carbon dioxide increased with time reaching maximum values of 0.49 and 0.22% and then declined reaching 0.06 and 0.08% by the end of the experiment for the runs with initial pH of 8.64 and 7.00, respectively. A strong correlation between the concentration of carbon dioxide in the exhaust gas and the temperature of the shrimp shells was observed. The initial moisture content of 60% fell below 25.5 and 21.5% and the galactose concentration decreased from the initial value of 20 to 1.48% and 6.17% by the end of the deproteinization process for the runs with initial pH of 8.64 and 7.00, respectively. Although the protease activity increased by 3.3-6.3 fold, the reduction in the protein concentration did not correspond to the increase in the protease activity due to the high pH of the shrimp shells. The chitin concentration increased from an initial value of 16.56 to final values of 22.68 and 21.35 for the initial pH of 8.64 and 7.00, respectively. The spent shrimp shells obtained from the run with the initial pH of 8.64 were wet and had a pale pink-orange color with some tan patches, whereas the spent shrimp shells obtained from the with the initial pH of 8.64 appeared dry and had a gray-black color due to the presence of A. niger spores. The use of lactic acid to lower the pH of shrimp shells inhibited the growth of A. niger and protease production and activity and enhanced sporulation. The existence of the pink-orange color was an indication of the presence of pigments, which were not utilized during the fermentation process. Key words: Shrimp shells, Aspergillus niger, deproteinization, protein, protease, chitin, galactose, temperature, pH, moisture content.

Antimicrobial Activity of Lactic Acid Against Pathogen and Spoilage Microorganisms

Preliminary examination of the antimicrobial activity of lactic acid against nine bacteria (Escherichia coli, Proteus mirabilis, Salmonella enteritidis, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus and Bacillus megaterium) and three yeasts (Rhodotorula sp., Saccharomyces cerevisiae and Candida albicans) was performed using disc diffusion and broth microdilution method. At a concentration of 321 mg/mL, inhibition zones ranged from 24.0 mm (Es. coli) to 38.3 mm (En. faecalis) for the tested bacteria. The inhibition zones of the yeasts ranged from 11.3 mm (Sac. cerevisiae) to 14.0 mm (Rhodotorula sp.). Lactic acid minimal inhibitory concentration for bacteria was ≥1.25 mg/mL, while minimal biocide concentration was ≥2.50 mg/mL. Minimal inhibitory concentration for yeasts was ≥12.50 mg/mL, while minimal fungicidal concentration was ≥25.00 mg/mL. The obtained results showed that lactic acid could be used as an efficient natural antimicrobial agent improving the safety of all-natural foods. Practical Applications Consumer perception that synthetic food additives may be associated with potential toxicological problems has recently generated interest for the use of naturally derived compounds in the food industry. The use of lactic acid is considered as a good alternative and may be more acceptable to consumers than synthetic food additives because of its natural origin, potential antimicrobial activity, as well as preservative, antioxidant, flavoring and acidifying properties as well as low cost. For ensuring food safety, combination of lactic acid with other natural antimicrobial agents or other preservation methods should be considered. Therefore, there is a potential for lactic acid usage in the development of eco-friendly technology which ensures food safety.

Acid environments affect biofilm formation and gene expression in isolates of Salmonella enterica Typhimurium DT104

The aim of this study was to examine the survival and potential virulence of biofilm-forming Salmonella Typhimurium DT104 under mild acid conditions. Salmonella Typhimurium DT104 employs an acid tolerance response (ATR) allowing it to adapt to acidic environments. The threat that these acid adapted cells pose to food safety could be enhanced if they also produce biofilms in acidic conditions. The cells were acid-adapted by culturing them in 1% glucose and their ability to form biofilms on stainless steel and on the surface of Luria Bertani (LB) broth at pH7 and pH5 was examined. Plate counts were performed to examine cell survival. RNA was isolated from cells to examine changes in the expression of genes associated with virulence, invasion, biofilm formation and global gene regulation in response to acid stress. Of the 4 isolates that were examined only one (1481) that produced a rigid biofilm in LB broth at pH7 also formed this same structure at pH5. This indicated that the lactic acid severely impeded the biofilm producing capabilities of the other isolates examined under these conditions. Isolate 1481 also had higher expression of genes associated with virulence (hilA) and invasion (invA) with a 24.34-fold and 13.68-fold increase in relative gene expression respectively at pH5 compared to pH7. Although genes associated with biofilm formation had increased expression in response to acid stress for all the isolates this only resulted in the formation of a biofilm by isolate 1481. This suggests that in addition to the range of genes associated with biofilm production at neutral pH, there are genes whose protein products specifically aid in biofilm production in acidic environments. Furthermore, it highlights the potential for the use of lactic acid for the inhibition of Salmonella biofilms.

Ultrasound-assisted Intensification of Extraction of Astaxanthin from Phaffia rhodozyma

Phaffia rhodozyma is one of the potent organisms for production of astaxanthin, though the recovery poses significant problems mostly due to the thick cell wall which hinders the solvent extraction of astaxanthin. An intensified greener approach of extraction of astaxanthin from P. rhodozyma using ultrasound and lactic acid has been demonstrated in the present work. The process is based on the use of lactic acid as the medium for disruption and ethanol as solvent for extraction and hence can be considered as green approach for extraction. The effect of different operating parameters such as type of solvent, temperature, time, ultrasonic power and duty cycle on the extraction yields has been demonstrated using one variable at a time approach. The maximum yield of astaxanthin (90%) was obtained for the ultrasound-assisted extraction approach based on the use of 3 M lactic acid, disruption time of 15 min, ultrasonic power of 80 W and duty cycle of 60%. Overall, the ultrasound-assisted approach showed intensification in terms of high extraction efficiency and use of greener solvents as well as requirement of lower quantum of chemicals.