Displaying publications 21 - 40 of 123 in total

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  1. Fulltext Chitosan Epoxidized Natural Rubber Biocomposites for Sorption and Biodegradability Studies
    Raju G, Mas Haris MRH, Azura AR, Ahmed Mohamed Eid AM
    ACS Omega, 2020 Nov 10;5(44):28760-28766.
    PMID: 33195929 DOI: 10.1021/acsomega.0c04081
    The slow-release mechanism of copper into soil followed by soil biodegradation was studied using the chitosan (CTS)/epoxidized natural rubber (ENR) biocomposite. The biocomposite was prepared by homogenizing CTS in ENR50 (ENR with about 50% epoxy content) latex in the presence of curing agents and acetic acid. It was found that the adsorption property of the biocomposite was very much influenced by chitosan loading, where 20phrCTS-t-ENR biocomposite can absorb 76.31% of Cu(II) ions. The desorption study indicates that the copper (II) ion can be released at a very slow and control phase as proven by the kinetic study using zero-order, first-order, Higuchi, and Korsmeyer Peppas equations. The slow-release studies comply with the Higuchi square-root equation, indicating that the release process is diffusion-controlled. Results of desorption and biodegradation process suggest that this biocomposite has the potential use of being a slow-release matrix in the field of agriculture.
    Matched MeSH terms: Acetic Acid
  2. Fulltext Vibrational analysis of Li1+xAlxTi2-x(PO4)3 (0.0 ≤ x ≤ 0.5) glass ceramic electrolytes prepared by acetic acid-assisted sol-gel method
    Hamidi, M., Mohamed, S.N., Mustapha, R.I.P.R., Hassan, O.H., Yahya, M.Z.A.
    Scientific Research Journal, 2015;12(2):0-0.
    MyJurnal
    In this study, Li1+xAlxTi2-x(PO4)3 (0.0 ≤ x ≤ 0.5) was prepared by acetic acid-assisted sol-gel method. The structural properties of NASICON phosphates material with chemical formula LiTi2(PO4)3 were observed using the Fourier transform infrared spectroscopy. NASICON is a family of crystalline phosphate with a general network system consisting of PO4 tetrahedra, thus bands were assigned by vibrations contributed by basic phosphates, in the wavenumber region between 1300 cm-1 and 600 cm-1. Experimental spectra indicated that all Li1+xAlxTi2-x(PO4)3 (0.0 ≤ x ≤ 0.5), heat treated at 600°C and 700°C for 3 hours in air, samples showed the presence of phosphate peaks with shift in frequency as Al3+ is substituted into the structure, and with increasing temperatures. Some bands broadened and overlapped causing it hard to analyze the arising bands. It however determined the existence of NASICON structure in all of the samples under study.
    Matched MeSH terms: Acetic Acid
  3. Fulltext Bioconversion of Leachate to Acetic and Butyric acid by Clostridium butyricum NCIMB 7423 in membrane fermentor
    Othman, M.F., Tamat, M.R., Wan Nadiah, W.A., Serri, N.A., Aziz, H.A., Tajarudin, H.A.
    Pertanika Journal of Science & Technology, 2017;25(108):39-48.
    MyJurnal
    Landfill leachate imposes a huge problem to the environment and human beings. This work focused on bioconversion of leachate to acetic and butyric acids by Clostridium butyricum NCIMB 7423. A continuous stirred tank reactor (CSTR) was applied and connected to fabricate membrane module. The leachate was collected from Pulau Burung Landfill Site (PBLS), Nibong Tebal, Penang. Prior to fermentation, leachate was treated to remove volatile fatty acid and adjusted to meet the minimum requirement of nutrients for anaerobic fermentation. Synthetic medium fermentation acts as a benchmark to the leachate fermentation. The outcomes indicated that the yield of acetic acid and butyric acid in synthetic medium fermentation was 0.70 g/L and 0.71 g/L, respectively. Meanwhile, leachate fermentation showed that the yield of acetic and butyric acid was 0.93 g/L and 1.86 g/L, respectively. High production of acetic and butyric acid showed that leachate fermentation is a green alternative to produce a cleaner product.
    Matched MeSH terms: Acetic Acid
  4. Fulltext Screening of significant factors in collagen extraction from hybrid Clarias sp. using a statistical tool
    Kiew, P.L., Mat Don, M.
    International Food Research Journal, 2013;20(4):1913-1920.
    MyJurnal
    Extraction of collagen from muscles of cultured catfish (Clarias gariepinus × C. macrocephalus) with the aid of pepsin digestion was investigated using a statistical tool. Fractional factorial design (FFD) was applied to evaluate the effects of eight process parameters: acetic acid concentration, acid extraction time, acid extraction temperature, acetic acid to muscles ratio, NaOH concentration, NaOH to muscles ratio, NaOH treatment time, and stirring speed. Contribution of every parameter in influencing the extraction efficiency was evaluated and factors that significantly affected the extraction were elucidated by employing experimental design and analysis of variance in FFD. The result of first order factorial design showed that acetic acid concentration, acid extraction time, acid to muscles ratio, and stirring speed had significant effect (P < 0.05) to the yield of pepsin soluble collagen (PSC) obtained at the end of the experiment. Effects of these process factors on the efficiency of collagen extraction were investigated, and are discussed in detail. Optimum conditions were found at 0.5 M acetic acid, 16 hr extraction period, solvent to muscles ratio at 25 ml/g, and stirring speed of 400 rpm, resulting in yield of PSC as high as 211.49 ± 15.51 mg/g.
    Matched MeSH terms: Acetic Acid
  5. Electrochemical behaviour of Ni and Ni-PVC electrodes for the electroxidation of ethanol
    Mohd Syafiq Hamdan, Norazzizi Nordin, Fathrita Mohd Amir, Mohamed Rozali Othman
    Sains Malaysiana, 2011;40:1421-1427.
    In this study, two nickel based electrodes were prepared; nickel foil and nickel-polyvinylchloride (Ni-PVC), in order to study their electrochemical behavior using cyclic voltammetry, CV and chronocoulometry, CC. Ni electrode was prepared from Ni metal foil while Ni-PVC electrode was prepared by mixing a weighed portion of Ni powder and PVC in THF solvent, swirled until the suspension was homogeneous and drying the suspension in an oven at 50oC for 3 h. The dry sample was then placed in a 1 cm diameter stainless steel mould and pressed at 10 ton/cm2. From CV data, Ni-PVC electrode showed a better electrochemical behavior compared to Ni metal foil electrode. The use of Ni-PVC electrode at higher concentration of supporting electrolyte (1.0 M KOH) was better than at lower concentration of the same supporting electrolyte in electroxidation of ethanol. In addition to acetic acid, the oxidation of ethanol also produced ethyl acetate and acetaldehyde.
    Matched MeSH terms: Acetic Acid
  6. Fulltext Determination of the Major Component of Water Fraction of Katuk (Sauropus androgynous (L.) Merr.) Leaves by Liquid Chromatography-Mass Spectrometry
    Mustarichie R, Salsabila T, Iskandar Y
    J Pharm Bioallied Sci, 2019 Dec;11(Suppl 4):S611-S618.
    PMID: 32148372 DOI: 10.4103/jpbs.JPBS_205_19
    Background: The katuk leaf (Sauropus androgynous (L.) Merr.) is one of the plants that are used to overcome baldness by the people of Kampung Mak Kemas, Malaysia. It is suspected that secondary metabolites contained in katuk leaves play a key role in stimulating hair growth.

    Aims and Objectives: The aim of this study was to identify the optimum method to obtain one of the chemical compounds in the water fraction and to identify the hypothesized chemical isolates in the water fraction katuk leave's ethanol extract.

    Materials and Methods: The methods used in this study included the collection and determination of the katuk plant, the processing of the katuk, phytochemical filtrating, extracting with ethanol 96%, and fractionation using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water solvents The water fraction of katuk leaves was analyzed by its components by thin-layer chromatography using the stationary phase of silica gel 60 F254, developer of n-butanol:acetic acid:water (4:1:5), and detection under ultraviolet (UV) light at a wavelength of 366 and 254nm, as well as with vanillin-sulfuric acid reagent. To isolate the compounds from water fraction of katuk leaves, it was then eluted with a vacuum column chromatography by eluent with a level polarity that would get 11 subfractions. Each subfraction was checked by two-dimensional thin-layer chromatography to see subfraction purity characterized by the appearance of a spot on the chromatogram plate. The isolate was analyzed using spot test, ultraviolet-visible spectrophotometer, infrared spectrophotometer, and liquid chromatography-mass spectrometry.

    Results: The isolate was an alkaloid compound with a molecular mass of 406.3131 m/z with the molecular formula C21H39N6O2 as S, S-5, 5'-amino-4,4'-dihexyl-propyldihydropyrazol-3, 3-one.

    Conclusion: One of the chemical compounds contained in the water fraction of the ethanol extract of the katuk leaf was an alkaloid group.

    Matched MeSH terms: Acetic Acid
  7. Anti-nociceptive effect of caralluma edulis on peripheral and central pain pathways
    Firdoos S, Khan AU, Ali F
    Sains Malaysiana, 2017;46:1859-1863.
    The purpose of the present research was to evaluate the phytochemical content and analgesic effect of Caralluma edulis
    (Ce.Cr). Established methods were used for phytochemical analysis of plant. The anti-nociceptic activity of Ce.Cr was
    scrutinized using acetic acid-induced writhings, tail immersion and hot plate methods. Ce.Cr was tested positive for the
    presence of therapeutically active metabolites such as alkaloids, flavonoids, glycosides, phenol, tannins, terpenoids and
    saponins. Ce.Cr at the dose of 10, 30 and 100 mg/kg inhibited acetic acid-induced abdominal writhes and increase the
    latency time to thermal stimuli in both tail immersion and hot plate tests, similar to standard drug. These results showed
    that the ethanolic extract of Caralluma edulis possesses anti-nociceptive property.
    Matched MeSH terms: Acetic Acid
  8. Fulltext Physicochemical characteristics of gummy added with sutchi catfish (Pangasius hypophthalmus) gelatin
    Normah, I.
    International Food Research Journal, 2015;22(3):1059-1066.
    MyJurnal
    Gelatin from sutchi catfish (Pangasius hypophthalmus) skin was extracted and applied in the preparation of gummy in order to determine the suitability of sutchi catfish gelatin in gummy production. The skin was subjected to pre-treatment in the following sequence; 0.8M NaCl, 0.19 N NaOH followed by 0.12 N acetic acid prior to 12 hours extraction in distilled water at 50oC. The physicochemical characteristics of sutchi catfish gelatin was analysed and compared with the commercial bovine gelatin. Gummy added with sutchi catfish gelatin was also compared with gummy added with commercial gelatin. Analysis comprises of yield, gel strength, setting point and setting time, amino acid composition, texture profile analysis and sensory evaluation. The extraction resulted in 14.47% yield of gelatin. Sutchi catfish gelatin showed higher gel strength value (360.86 g) compared to the commercial gelatin (217.37 g) which is in accordance with proline content. Texture profile analysis showed that gummies prepared using sutchi catfish gelatin had significantly higher (p
    Matched MeSH terms: Acetic Acid
  9. Acetic acid induces pH-independent cellular energy depletion in Salmonella enterica
    Tan SM, Lee SM, Dykes GA
    Foodborne Pathog Dis, 2015 Mar;12(3):183-9.
    PMID: 25562466 DOI: 10.1089/fpd.2014.1853
    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH.
    Matched MeSH terms: Acetic Acid/pharmacology*
  10. Fulltext Effects of NAA and BAP, double-layered media, and light distance on in vitro regeneration of Nelumbo nucifera Gaertn. (lotus), an aquatic edible plant
    Mahmad N, Taha RM, Othman R, Saleh A, Hasbullah NA, Elias H
    ScientificWorldJournal, 2014;2014:745148.
    PMID: 24895660 DOI: 10.1155/2014/745148
    In vitro direct regeneration of Nelumbo nucifera Gaertn. was successfully achieved from immature explants (yellow plumule) cultured on a solid MS media supplemented with combinations of 0.5 mg/L BAP and 1.5 mg/L NAA which resulted in 16.00 ± 0.30 number of shoots per explant and exhibited a new characteristic of layered multiple shoots, while normal roots formed on the solid MS basal media. The double-layered media gave the highest number of shoots per explant with a ratio of 2 : 1 (liquid to solid) with a mean number of 16.67 ± 0.23 shoots per explant with the formation of primary and secondary roots from immature explants. In the study involving light distance, the tallest shoot (16.67 ± 0.23 mm) obtained from the immature explants was at a light distance of 200 mm from the source of inflorescent light (1000 lux). The plantlets were successfully acclimatized in clay loam soil after 8 months being maintained under in vitro conditions.
    Matched MeSH terms: Acetic Acid/pharmacology*
  11. Acetylation of glycerol to biofuel additives over sulfated activated carbon catalyst
    Khayoon MS, Hameed BH
    Bioresour Technol, 2011 Oct;102(19):9229-35.
    PMID: 21840708 DOI: 10.1016/j.biortech.2011.07.035
    Oxygenated fuel additives can be produced by acetylation of glycerol. A 91% glycerol conversion with a selectivity of 38%, 28% and 34% for mono-, di- and triacetyl glyceride, respectively, was achieved at 120 °C and 3 h of reaction time in the presence of a catalyst derived from activated carbon (AC) treated with sulfuric acid at 85 °C for 4h to introduce acidic functionalities to its surface. The unique catalytic activity of the catalyst, AC-SA5, was attributed to the presence of sulfur containing functional groups on the AC surface, which enhanced the surface interaction between the glycerol molecule and acyl group of the acetic acid. The catalyst was reused in up to four consecutive batch runs and no significant decline of its initial activity was observed. The conversion and selectivity variation during the acetylation is attributed to the reaction time, reaction temperature, catalyst loading and glycerol to acetic acid molar ratio.
    Matched MeSH terms: Acetic Acid/metabolism*
  12. Simultaneous saccharification and fermentation of ground corn stover for the production of fuel ethanol using Phanerochaete chrysosporium, Gloeophyllum trabeum, Saccharomyces cerevisiae, and Escherichia coli K011
    Vincent M, Pometto AL, van Leeuwen JH
    J Microbiol Biotechnol, 2011 Jul;21(7):703-10.
    PMID: 21791956
    Enzymatic saccharification of corn stover using Phanerochaete chrysosporium and Gloeophyllum trabeum and subsequent fermentation of the saccharification products to ethanol by Saccharomyces cerevisiae and Escherichia coli K011 were achieved. Prior to simultaneous saccharification and fermentation (SSF) for ethanol production, solid-state fermentation was performed for four days on ground corn stover using either P. chrysosporium or G. trabeum to induce in situ cellulase production. During SSF with S. cerevisiae or E. coli, ethanol production was the highest on day 4 for all samples. For corn stover treated with P. chrysosporium, the conversion to ethanol was 2.29 g/100 g corn stover with S. cerevisiae as the fermenting organism, whereas for the sample inoculated with E. coli K011, the ethanol production was 4.14 g/100 g corn stover. Corn stover treated with G. trabeum showed a conversion 1.90 and 4.79 g/100 g corn stover with S. cerevisiae and E. coli K011 as the fermenting organisms, respectively. Other fermentation co-products, such as acetic acid and lactic acid, were also monitored. Acetic acid production ranged between 0.45 and 0.78 g/100 g corn stover, while no lactic acid production was detected throughout the 5 days of SSF. The results of our experiment suggest that it is possible to perform SSF of corn stover using P. chrysosporium, G. trabeum, S. cerevisiae and E. coli K011 for the production of fuel ethanol.
    Matched MeSH terms: Acetic Acid/metabolism
  13. Optimization of acetic acid production from synthesis gas by chemolithotrophic bacterium--Clostridium aceticum using statistical approach
    Sim JH, Kamaruddin AH
    Bioresour Technol, 2008 May;99(8):2724-35.
    PMID: 17697778
    Efforts in optimizing reducing agents, cysteine-HCl.H2O and sodium sulfide in order to attain satisfactory responses during acetic acid fermentation have been carried out in this study. Cysteine-HCl.H2O each with five concentrations (0.00-0.50 g/L) was optimized one at a time and followed by sodium sulfide component (0.00-0.50 g/L). Response surface methodology (RSM) was used to determine the optimum concentrations of cysteine-HCl.H2O and sodium sulfide. The statistical analysis showed that the amount of cells produced and efficiency in CO conversion were not affected by sodium sulfide concentration. However, sodium sulfide is required as it does influence the acetic acid production. The optimum reducing agents for acetic acid fermentation was at 0.30 g/L cysteine-HCl.H2O and sodium sulfide respectively and when operated for 60 h cultivation time resulted in 1.28 g/L acetic acid production and 100% CO conversion.
    Matched MeSH terms: Acetic Acid/metabolism*
  14. Growth of Bifidobacterium longum BB536 in medida (fermented cereal porridge) and their survival during refrigerated storage
    Kabeir BM, Abd-Aziz S, Muhammad K, Shuhaimi M, Yazid AM
    Lett Appl Microbiol, 2005;41(2):125-31.
    PMID: 16033508
    To develop medida, a Sudanese fermented thin porridge as a probiotic dietary adjunct with high total solids.
    Matched MeSH terms: Acetic Acid/analysis
  15. Varieties, production, composition and health benefits of vinegars: A review
    Ho CW, Lazim AM, Fazry S, Zaki UKHH, Lim SJ
    Food Chem, 2017 Apr 15;221:1621-1630.
    PMID: 27979138 DOI: 10.1016/j.foodchem.2016.10.128
    Vinegars are liquid products produced from the alcoholic and subsequent acetous fermentation of carbohydrate sources. They have been used as remedies in many cultures and have been reported to provide beneficial health effects when consumed regularly. Such benefits are due to various types of polyphenols, micronutrients and other bioactive compounds found in vinegars that contribute to their pharmacological effects, among them, antimicrobial, antidiabetic, antioxidative, antiobesity and antihypertensive effects. There are many types of vinegars worldwide, including black vinegar, rice vinegar, balsamic vinegar and white wine vinegar. All these vinegars are produced using different raw materials, yeast strains and fermentation procedures, thus giving them their own unique tastes and flavours. The main volatile compound in vinegar is acetic acid, which gives vinegar its strong, sour aroma and flavour. Other volatile compounds present in vinegars are mainly alcohols, acids, esters, aldehydes and ketones. The diversity of vinegars allows extensive applications in food.
    Matched MeSH terms: Acetic Acid/analysis*
  16. Bio-hydrogen production using a two-stage fermentation process
    Alalayah WM, Kalil MS, Kadhum AA, Jahim JM, Jaapar SZ, Alauj NM
    Pak J Biol Sci, 2009 Nov 15;12(22):1462-7.
    PMID: 20180320
    A two-stage fermentation process consisting of dark and photo-fermentation periods was carried out in a batch reactor. In the first stage, glucose was fermented in the dark stage using Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564; CSN1-4) to produce acetate, CO2 and H2. The acetate produced in the first stage is fermented to H2 and CO2 by Rhodobacter sphaeroides NCIMB 8253 for further hydrogen production in the second, illuminated stage. The yield of hydrogen in the first stage was about 3.10 mol H2 (mol glucose)(-1) at a glucose concentration of 10 g L(-1), pH 6 +/- 0.2 and 37 degrees C and the second stage yield was about 1.10-1.25 mol H2 (mol acetic acid)(-1) at pH 6.8 +/- 0.2 and 32 degrees C, without removal of the Clostridium CSN1-4. The overall yield of hydrogen in the two-stage process, with glucose as the main substrate was higher than single-stage fermentation.
    Matched MeSH terms: Acetic Acid/metabolism
  17. Fulltext Lactobacillus plantarum strain HT-W104-B1: potential bacterium isolated from Malaysian fermented foods for control of the dermatophyte Trichophyton rubrum
    Danial AM, Medina A, Magan N
    World J Microbiol Biotechnol, 2021 Feb 24;37(4):57.
    PMID: 33625606 DOI: 10.1007/s11274-021-03020-7
    The objective was to screen and evaluate the anti-fungal activity of lactic acid bacteria (LABs) isolated from Malaysian fermented foods against two Trichophyton species. A total of 66 LAB strains were screened using dual culture assays. This showed that four LAB strains were very effective in inhibiting growth of T. rubrum but not T. interdigitale. More detailed studies with Lactobacillus plantarum strain HT-W104-B1 showed that the supernatant was mainly responsible for inhibiting the growth of T. rubrum. The minimum inhibitory concentration (MIC), inhibitory concentration, the 50% growth inhibition (IC50) and minimum fungicide concentration (MFC) were 20 mg/mL, 14 mg/mL and 30 mg/mL, respectively. A total of six metabolites were found in the supernatant, with the two major metabolites being L-lactic acid (19.1 mg/g cell dry weight (CDW)) and acetic acid (2.2 mg/g CDW). A comparative study on keratin agar media showed that the natural mixture in the supernatants predominantly contained L-lactic and acetic acid, and this significantly controlled the growth of T. rubrum. The pure two individual compounds were less effective. Potential exists for application of the natural mixture of compounds for the treatment of skin infection by T. rubrum.
    Matched MeSH terms: Acetic Acid/metabolism; Acetic Acid/pharmacology
  18. Fulltext Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin
    See SF, Ghassem M, Mamot S, Babji AS
    J Food Sci Technol, 2015 Feb;52(2):753-62.
    PMID: 25694683 DOI: 10.1007/s13197-013-1043-6
    Pretreatments with different types of alkali and acid were compared to determine their effects on gelatin extraction from African catfish (Clarias gariepinus) skin. The study was divided into three parts. In the first part, the skins were only treated with alkaline (Ca(OH)2 or NaOH) solution or pretreated with acetic acid solution. For second part, combination of alkali and acid pretreatment was carried out. For the third part, the skins were first treated with NaOH solution, followed by the treatment with acetic acid, citric acid or sulfuric acid solution. Functional properties including the yield of protein recovery, gel strength, viscosity, pH and viscoelastic properties were determined on gelatins obtained with different pretreatment conditions. Pretreatment with alkali removed noncollagenous proteins effectively, whilst acid pretreatment induced some loss of collagenous proteins. Combination of alkali and acid pretreatment not only removed the noncollagenous proteins and caused a significant amount of swelling, but also provided the proper pH condition for extraction, during which some cross-linkages could be further destroyed but with less breakage of intramolecular peptide chains. Pretreatment of catfish skins with 0.2 N NaOH followed by 0.05 M acetic acid improved yield of protein recovery, gel strength, viscosity, melting temperature and gelling temperature of gelatin extract.
    Matched MeSH terms: Acetic Acid
  19. Online preconcentration of arsenic compounds by dynamic pH junction-capillary electrophoresis
    Jaafar J, Irwan Z, Ahamad R, Terabe S, Ikegami T, Tanaka N
    J Sep Sci, 2007 Feb;30(3):391-8.
    PMID: 17396598
    An online preconcentration technique by dynamic pH junction was studied to improve the detection limit for anionic arsenic compounds by CE. The main target compound is roxarsone, or 3-nitro-4-hydroxyphenylarsonic acid, which is being used as an animal feed additive. The other inorganic and organoarsenic compounds studied are the possible biotransformation products of roxarsone. The arsenic species were separated by a dynamic pH junction in a fused-silica capillary using 15 mM phosphate buffer (pH 10.6) as the BGE and 15 mM acetic acid as the sample matrix. CE with UV detection was monitored at a wavelength of 192 nm. The influence of buffer pH and concentration on dynamic pH junction were investigated. The arsenic species focusing resulted in LOD improvement by a factor of 100-800. The combined use of C18 and anion exchange SPE and dynamic pH junction to CE analysis of chicken litter and soils helps to increase the detection sensitivity. Recoveries of spiked samples ranged between 70 and 72%.
    Matched MeSH terms: Acetic Acid
  20. Fulltext Effects of glucose, ethanol and acetic acid on regulation of ADH2 gene from Lachancea fermentati
    Yaacob N, Mohamad Ali MS, Salleh AB, Abdul Rahman NA
    PeerJ, 2016;4:e1751.
    PMID: 26989608 DOI: 10.7717/peerj.1751
    Background. Not all yeast alcohol dehydrogenase 2 (ADH2) are repressed by glucose, as reported in Saccharomyces cerevisiae. Pichia stipitis ADH2 is regulated by oxygen instead of glucose, whereas Kluyveromyces marxianus ADH2 is regulated by neither glucose nor ethanol. For this reason, ADH2 regulation of yeasts may be species dependent, leading to a different type of expression and fermentation efficiency. Lachancea fermentati is a highly efficient ethanol producer, fast-growing cells and adapted to fermentation-related stresses such as ethanol and organic acid, but the metabolic information regarding the regulation of glucose and ethanol production is still lacking. Methods. Our investigation started with the stimulation of ADH2 activity from S. cerevisiae and L. fermentati by glucose and ethanol induction in a glucose-repressed medium. The study also embarked on the retrospective analysis of ADH2 genomic and protein level through direct sequencing and sites identification. Based on the sequence generated, we demonstrated ADH2 gene expression highlighting the conserved NAD(P)-binding domain in the context of glucose fermentation and ethanol production. Results. An increase of ADH2 activity was observed in starved L. fermentati (LfeADH2) and S. cerevisiae (SceADH2) in response to 2% (w/v) glucose induction. These suggest that in the presence of glucose, ADH2 activity was activated instead of being repressed. An induction of 0.5% (v/v) ethanol also increased LfeADH2 activity, promoting ethanol resistance, whereas accumulating acetic acid at a later stage of fermentation stimulated ADH2 activity and enhanced glucose consumption rates. The lack in upper stream activating sequence (UAS) and TATA elements hindered the possibility of Adr1 binding to LfeADH2. Transcription factors such as SP1 and RAP1 observed in LfeADH2 sequence have been implicated in the regulation of many genes including ADH2. In glucose fermentation, L. fermentati exhibited a bell-shaped ADH2 expression, showing the highest expression when glucose was depleted and ethanol-acetic acid was increased. Meanwhile, S. cerevisiae showed a constitutive ADH2 expression throughout the fermentation process. Discussion. ADH2 expression in L. fermentati may be subjected to changes in the presence of non-fermentative carbon source. The nucleotide sequence showed that ADH2 transcription could be influenced by other transcription genes of glycolysis oriented due to the lack of specific activation sites for Adr1. Our study suggests that if Adr1 is not capable of promoting LfeADH2 activation, the transcription can be controlled by Rap1 and Sp1 due to their inherent roles. Therefore in future, it is interesting to observe ADH2 gene being highly regulated by these potential transcription factors and functioned as a promoter for yeast under high volume of ethanol and organic acids.
    Matched MeSH terms: Acetic Acid
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