Abstract  Two independent isolates of a Gram-stain-positive, facultatively anaerobic, motile, rod-shaped bacterium were recovered from cheonggukjang, a Korean fermented soybean paste food product. Preliminary sequencing analysis of the 16S rRNA gene indicated that these strains were related most closely to Bacillus sonorensis KCTC-13918T and Bacillus licheniformis DSM 13T. In phenotypic characterization, the novel strains were found to grow between 15 and 55 °C and to tolerate up to 8 % (w/v) NaCl. Furthermore, the strains grew in media of pH 5-10 (optimal growth at pH 7.0). The predominant cellular fatty acids were anteiso-C15 : 0 and iso-C15 : 0.The isoprenoid quinone was menaquinone 7 (MK-7). The cell-wall peptidoglycan contained meso-diaminopimelic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unknown glycolipid. Draft genomes of the two strains were determined and in silico DNA-DNA hybridizations with their nearest neighbour (B. sonorensis KCTC-13918T) revealed 29.9 % relatedness for both strains. Phylogenomic analysis of the genomes was conducted with the core genome (799 genes) of all strains in the Bacillus subtilis group and the two strains formed a distinct monophyletic cluster. In addition, the strains differed from the two most closely related species in that they did not metabolize maltose, d-galactose, d-sorbitol or d-gluconic acid. The DNA G+C content was 45.9 mol%. Based upon the consensus of phylogenetic and phenotypic analyses, these strains represent a novel species of the genus Bacillus, for which the name Bacillus glycinifermentans sp. nov. is proposed. The type strain is GO-13T ( = KACC 18425T = NRRL B-65291T).

Abstract  Background: Aliphatic (poly)hydroxy carboxylic acids [(P)HCA] occur in natural, e.g. soils, and in technical (waste disposal sites, nuclear waste repositories) compartments . Their distribution, mobility and chemical reactivity, e.g. complex formation with metal ions and radionuclides, depend, among others, on their adsorption onto mineral surfaces. Aluminium hydroxides, e.g. gibbsite [α-Al(OH)3], are common constituents of related solid materials and mimic the molecular surface properties of clay minerals. Thus, the study was pursued to characterize the adsorption of glycolic, threonic, tartaric, gluconic, and glucaric acids onto gibbsite over a wide pH and (P)HCA concentration range. To consider specific conditions occurring in radioactive wastes, adsorption applying an artificial cement pore water (pH 13.3) as solution phase was investigated additionally.

Results: The sorption of gluconic acid at pH 4, 7, 9, and 12 was best described by the "two-site" Langmuir isotherm, combining "high affinity" sorption sites (adsorption affinity constants [Formula: see text] > 1 L mmol-1, adsorption capacities < 6.5 mmol kg-1) with "low affinity" sites ([Formula: see text] < 0.1 L mmol-1, adsorption capacities ≥ 19 mmol kg-1). The total adsorption capacities at pH 9 and 12 were roughly tenfold of that at pH 4 and 7. The S-shaped pH sorption edge of gluconic acid was modelled applying a constant capacitance model, considering electrostatic interactions, hydrogen bonding, surface complex formation, and formation of solved polynuclear complexes between Al3+ ions and gluconic acid. A Pearson and Spearman rank correlation between (P)HCA molecular properties and adsorption parameters revealed the high importance of the size and the charge of the adsorbates.

Conclusions: The adsorption behaviour of (P)HCAs is best described by a combination of adsorption properties of carboxylic acids at acidic pH and of polyols at alkaline pH. Depending on the molecular properties of the adsorbates and on pH, electrostatic interactions, hydrogen bonding, and ternary surface complexation contribute in varying degrees to the adsorption process. Linear distribution coefficients Kd between 8.7 and 60.5 L kg-1 (1 mmol L-1 initial PHCA concentration) indicate a considerable mineral surface affinity at very high pH, thus lowering the PHCA fraction available for the complexation of metal ions including radionuclides in solution and their subsequent mobilization.

Abstract  Gluconic acid is a multifunctional organic acid used as a bulk chemical in the food, feed, pharmaceutical, textile, metallurgy, detergent, paper, and construction industries. It is derived from glucose through a simple oxidation reaction catalyzed by glucose oxidase (EC 1.1.3.4.). Oxidation of the aldehyde group on C-1 of β-d-glucose to a carboxyl group results in the production of glucono-δ-lactone (C6H10O6) and hydrogen peroxide using molecular oxygen as the electron acceptor. Glucono-δ-lactone is further hydrolyzed to gluconic acid either spontaneously or by lactone-hydrolyzing enzyme. There are various approaches such as chemical, biochemical, and electrochemical available for its production, but microbial fermentation by Aspergillus niger using glucose oxidase is the most widely studied method. Microbial production of gluconic acid by bacteria, Gluconobacter, has also been demonstrated well. The enzyme involved in this process is glucose dehydrogenase. This chapter gives a review of microbial gluconic acid production; its recovery, properties, and applications; and the enzyme glucose oxidase.

Abstract  Agro-industrial by-products and wastes pose serious, widespread problems with considerable economic and environmental consequences in developed countries. However, many of the by-products contain large amounts of sugars that make them potentially excellent raw materials for the biotechnological production of added value products; in particular, by-products from perishables such as fruits can be highly useful for this aim. The growing significance and demand for gluconic acid have promoted an interest in integrating both issues as a strategy for the revalorization of these resources.

The pertinence of this strategy can be better understood by examining the properties of gluconic acid and its derivatives and their uses and production methods, especially biotechnological methods, to update the existing reviews on the topic.

Future advances in this direction may be promoted by the development of genetically modified organisms for the generation of new technological processes and the optimization of existing ones. Particular attention is paid to acetic acid bacteria. (C) 2016 Elsevier Ltd. All rights reserved.

Abstract  delta-D-Gluconolactone, delta-D-mannonolactone, and - for the first time - the thermodynamically unstable delta-D-galactonolactone have been prepared and isolated from DMF solution by oxidizing the corresponding sugars with Shvo's catalyst [(C4Ph4CO)(CO)(2)Ru](2) and a hydrogen acceptor. The preferred conformation of delta-D-galactonolactone in [D-6]DMSO solution has been determined by H-1 NMR spectroscopy experiments and DFT calculations to be H-4(3) and is compared to those of the previously established conformations of delta-D-gluconolactone (H-4(3)) and delta-D-mannonolactone (B-2,B-5). The conformations of the lactones suggest an explanation for their relative rates of isomerization to their respective 7-D-lactones by an intramolecular mechanism. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Abstract  Environmental Effect of Photoprocessing Chemicals Vol I and II (557).

Abstract  From previous work, it was observed that during growth on mixtures of acetate and aldose sugars the growth yield of the bacterium Acinetobacter calcoaceticus was increased when aldonolactone hydrolysis occurred. In this paper, the underlying mechanism was investigated by studying the relationship between cellular yield and lactone hydrolysis in a quantitative way. The literature on the kinetics of acid formation from aldonolactones was reviewed. It appears that the reaction pattern is composed of lactone isomerization and hydrolysis steps which occur in series. In the acid pH range, lactone interconversion is the rate-limiting step for acid formation, whereas above pH 7 hydrolysis is slowest. Only for D-gluconolactone could the detailed mechanistic kinetics be evaluated. For a number of other aldonolactones, including D-xylono- and D-galactonolactone, an empirical kinetic equation was derived. The reaction rate constants of these lactones are much smaller than for gluconolactone. The kinetic model for the hydrolysis of xylonolactone was experimentally verified, by application of the electrical charge balance to measurement data from A.calcoaceticus cultures. Comparison of the published biomass yield data and the calculated rate of lactone hydrolysis revealed that they do not quantitatively agree. It can be concluded that the observed relation between biomass yield and lactone hydrolysis is only apparent. The results demonstrate the power of the electrical charge balance in the study of processes in which charged compounds are being converted.

Abstract  Eight psychrotolerant, xylan-degrading strains of bacteria that were catalase-positive, oxidase-negative and able to reduce nitrate to nitrite were isolated from soil beneath moist non-acidic and acidic tundra in northern Alaska. The DNA G+C contents for the strains ranged from 46.4-50.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that each strain belonged to the genus Paenibacillus. The highest level of 16S rRNA gene similarity was found between the eight strains and Paenibacillus amylolyticus NRRL NRS-290(T) (98.9-99.1 %). However, despite relatively high 16S rRNA gene similarity, DNA-DNA hybridization, repetitive elements genotyping and phenotypic analysis revealed that at least two of the strains differed from P. amylolyticus NRRL NRS-290(T). DNA-DNA hybridization values between strain A10b(T) and P. amylolyticus NRRL NRS-290(T) (4.3 %), between strain B22a(T) and P. amylolyticus NRRL NRS-290(T) (48.8 %) and between strain A10b(T) and strain B22a(T) (11.0 %) were below those recommended by the ad hoc committee for those belonging to the same species. Significant phenotypic features that differentiate these novel strains from P. amylolyticus included their inability to utilize l-arabinose and ability to utilize glycogen as sole carbon sources. Unlike strains 1B4a and B22a(T), strains A6a and A10b(T) produced ethanol as an end product of glucose fermentation, utilized acetic acid and 2,3-butanediol and did not utilize d-gluconic acid. MK-7 was the major isoprenoid quinone and anteiso-C(15 : 0) was the most abundant fatty acid for strains A10b(T) and B22a(T). On the basis of these results, strains A10b(T) and B22a(T) are each considered to represent a novel species of the genus Paenibacillus, for which the names Paenibacillus tundrae sp. nov. and Paenibacillus xylanexedens sp. nov. are proposed, respectively. The type strain of Paenibacillus tundrae sp. nov. is A10b(T) (=NRRL B-51094(T)=DSM 21291(T)). The type strain of Paenibacillus xylanexedens sp. nov. is B22a(T) (=NRRL B-51090(T)=DSM 21292(T)).

Abstract  Gluconate derivatives are presented as a category. Gluconic acid and its mineral salts freely dissociate to the gluconate anion and the respective cations. Glucono-delta-lactone (GDL), the 1,5-inner ester of gluconic acid, is formed from the free acid by the removal of water. On the basis of these spontaneous chemical rearrangements, glucono-delta-lactone, gluconic acid and its sodium, calcium and potassium salts can be considered as a category, with all members sharing the same representative moiety, the gluconate anion. Manufacturing and uses of the category members are also interlinked. The data summarized in this report are focused on the environmental and health effects from the gluconate anion and read-across to the lactone but do not deal with specific effects of the cations. Thus toxicological effects related to the cationic components are not part of the present report.

Abstract  Phase equilibria governing the reactive extraction of gluconic acid from aqueous solution into solutions of trioctyl methylammonium chloride in the single solvents cyclohexane, hexane, 2,2,4-trimethyl pentane, 1-butanol, toluene, methyl isobutyl ketone, and ethyl acetate are investigated. All measurements were carried out at 298.15 K. The distribution coefficients, D, loading factors, Z, and extraction efficiencies, E, are derived. The maximum removal of gluconic acid is mass 69% with methyl isobutyl ketone with a 1.71 mol&BULL; L-1 initial concentration of trioctyl methylammonium chloride.

Abstract  During the SAFARI 2000 field campaign, both smoke aerosols from savanna fires and haze aerosols in the boundary layer and in the free troposphere were collected from an aircraft in southern Africa. These aerosol samples were analyzed for their water-soluble chemical components, particularly the organic species. A novel technique, electrospray ionization-ion trap mass spectrometry, was used concurrently with an ion chromatography system to analyze for carbohydrate species. Seven carbohydrates, seven organic acids, five metallic elements, and three inorganic anions were identified and quantified. On the average, these 22 species comprised 36% and 27% of the total aerosol mass in haze and smoke aerosols, respectively. For the smoke aerosols, levoglucosan was the most abundant carbohydrate species, while gluconic acid was tentatively identified as the most abundant organic acid. The mass abundance and possible source of each class of identified species are discussed, along with their possible formation pathways. The combustion phase of a fire had an impact on the chemical composition of the emitted aerosols. Secondary formation of sulfate, nitrate, levoglucosan, and several organic acids occurred during the initial aging of smoke aerosols. It is likely that under certain conditions, some carbohydrate species in smoke aerosols, such as levoglucosan, were converted to organic acids during upward transport.

Abstract  d‐Gluconic acid [526‐95‐4], 1,2,3,4,5‐pentahydroxy pentane‐1‐carboxylic acid, C6H12O7, Mr 196.16, was discovered in 1870 by Hlasiwetz and Habermann during the oxidation of glucose with chlorine. The substance was isolated in the form of its barium and calcium salts. Several authors subsequently reported that gluconic acid could be obtained by treatment of various mono‐, di‐, and polysaccharides with oxidizing agents such as elemental halogen, copper(II) or hexacyanoferrate(III) salts, or mercury(II) oxide. Depending on the type of sugar and the oxidant employed, byproducts of the reaction include formic acid, glycolic acid, oxalic acid, and carbon dioxide. As early as 1880 Boutroux recognized that gluconic acid was produced, together with acetic acid, by the oxidative action of Acetobacter aceti on glucose. This characteristic was also found to be associated with numerous other bacteria 1. Molliard was the first to report the presence of gluconic acid in cultures of Sterigmatocystis nigra, now known as Aspergillus niger 2. The currently preferred method for preparing gluconic acid and its derivatives with the aid of Aspergillus strains is based on the work of a number of authors 3. The catalytic activity of the enzyme glucose oxidase was first described by Müller 4. During the 1930s anodic oxidation was suggested for the preparation of calcium gluconate 5; proposals for catalytic oxidation of glucose with the aid of air or oxygen followed somewhat later 6.

Abstract  A novel C-2-specific sugar oxidoreductase, tentatively designated as pyranose 2-dehydrogenase, was purified 68-fold to apparent homogeneity (16.4 U/mg protein) from the mycelia of Agaricus bisporus, which expressed maximum activity of the enzyme during idiophasic growth in liquid media. Using 1,4-benzoquinone as an electron acceptor, pyranose 2-dehydrogenase oxidized D-glucose to D-arabino-2-hexosulose (2-dehydroglucose, 2-ketoglucose), which was identified spectroscopically through its N,N-diphenylhydrazone. The enzyme is highly nonspecific. D-,L-Arabinose, D-ribose, D-xylose, D-galactose, and several oligosaccharides and glycopyranosides were all converted to the corresponding 2-aldoketoses (aldosuloses) as indicated by TLC. D-Glucono-1,5-lactone, D-arabino-2-hexosulose, and L-sorbose were also oxidized at significant rates. UV/VIS spectrum of the native enzyme (lambda(max), 274, 362, and 465 nm) was consistent with a flavin prosthetic group. In contrast to oligomeric intracellular pyranose 2-oxidase (EC 1.1.3.10), pyranose 2-dehydrogenase is a monomeric glycoprotein (pI 4.2) incapable of reducing O-2 to H2O2 (> 5 X 10(4)-fold lower rate using a standard pyranose oxidase assay); pyranose 2-dehydrogenase is actively secreted into the extracellular fluid (up to 0.5 U/ml culture filtrate). The dehydrogenase has a native molecular mass of similar to 79 kDa as determined by gel filtration; its subunit molecular mass is similar to 75 kDa as estimated by SDS- PAGE. Two pH optima of the enzyme were found, one alkaline at pH 9 (phosphate buffer) and the other acidic at pH 4 (acetate buffer). Ag+, Hg2+, Cu2+, and CN- (10 mM) were inhibitory, while 50 mM acetate had an activating effect.

Abstract  Enterobacter intermedium, isolated from grass rhizosphere, exhibited a strong ability to solubilize insoluble phosphate. This bacterium oxidized glucose to gluconic acid and sequentially to 2-ketogluconic acid (2-KGA), which was identified using HPLC and GC-MS. The ability of E. intermedium to solubilize phosphate and produce 2-KGA produce in broth medium containing different components was monitored with air and without air supply. With an air supply, the production of 2-KGA markedly increased to about 110 g/l at day 10 in media containing 0.2 M gluconic acid, while it was about 65 g/l without gluconic acid addition. With an air supply, the concentration of soluble phosphate significantly decreased to 200-250 mg/l in media containing 1% CaCO3, whereas it was about 1000 mg/l without CaCO3 addition. Without an air supply, the concentration of 2-KGA and phosphate were negligible throughout the culture period.

Abstract  The solubility products of the calcium salts of two polyhydroxy ligands (PBL), isosaccharinate (ISA) and gluconate (GLUC), were measured. Solubility products of log K-delta,K-O = -6.22+/-0.03 at I = 0 and T = 20+/-1 degrees C for Ca(alpha-ISA)(2), and log K-S,K-O = -3.54+/-0.06 at I = 0 and T = 20+/-1 degrees C for Ca(GLUC)(2) were calculated ignoring the complexation equilibrium: Ca2+ + PHL- reversible arrow CaPHL+. If this complexation reaction is taken into account with log K-1(0) = 1.7, the values of the solubility products are log K-S,K-O = -6.53+/-0.02 at I = 0 For Ca(alpha-ISA)(2) and log K-S,K-O = -4.19+/-0.05 at I = 0 for Ca(GLUC)(2). Both dissolution reactions are endothermic. The standard free enthalpy change (Delta H degrees) for Ca(alpha-ISA)(2) is 40+/-1 kJ mol(-1) and 37+/-4 kJ mol(-1) for Ca(GLUC)(2). The enthalpy was assumed to be constant in the temperature range 7 < T < 90 degrees C. The calculated standard entropy change (Delta S degrees) is 17+/-5 J mol(-1) K-1 for Ca(alpha-ISA)(2) and 60+/-14 J mol(-1) K-1 for Ca(GLUC)(2).

Abstract  A study for screening and selection of mutants of Pseudomonas corrugata (NRRL B-30409) based on their phosphate solubilization ability, production of organic acids, and subsequent effect on plant growth at lower temperatures under in vitro and in situ conditions was conducted. Of a total 115 mutants tested, two (PCM-56 and PCM-82) were selected based on their greater phosphate solubilization ability at 21 degrees C in Pikovskaya's broth. The two mutants were found more efficient than wild-type strain for phosphate solubilization activity across a range of temperature from psychotropic (4 degrees C) to mesophilic (28 degrees C) in aerated GPS medium containing insoluble rock phosphate. High-performance liquid chromatography analysis showed that phosphate solubilization potential of wild-type and mutant strains were mediated by production of organic acids in the culture medium. The two efficient mutants and the wild strain oxidized glucose to gluconic acid and sequentially to 2-ketogluconic acid. Under in vitro conditions at 10 degrees C, the mutants exhibited increased plant growth as compared to wild type, indicating their functionality at lower temperatures. In greenhouse trials using sterilized soil amended with either soluble or rock phosphate, inoculation with mutants showed greater positive effect on all of the growth parameters and soil enzymatic activities. To the best of our knowledge, this is the first report on the development of phosphate solubilizing mutants of psychotropic wild strain of P. corrugata, native to the Indian Himalayan region.

Abstract  Lactonization and proton dissociation of sugar acids take place simultaneously in acidic aqueous solutions. The protonation-deprotonation processes are always fast, whilst the formation and hydrolysis of γ- and δ-lactones are usually slower. Thus, both thermodynamic and kinetic information are required for the complete understanding of these reactions. The protonation constant (Kp) of l-gulonate (Gul-) was determined from potentiometric and polarimetric measurements, while the individual lactonization constants (KL,γ and KL,δ) for l-gulonic acid (HGul) were obtained via13C NMR experiments. The applicability of this method was proven by measuring these well-known constants for d-gluconic acid (HGluc) and by comparing them to literature data. l-gulonic acid γ-lactone (γ-HGul) has remarkable stability in contrast with δ-HGul as well as γ- and δ-HGluc. The polarimetric measurement implies that the main factor responsible for the enhanced stability of γ-HGul is that its hydrolysis is much slower than that of δ-HGul. This higher stability of the γ-HGul ring over its δ-isomer was also confirmed by quantum chemical calculations. A new confirmed feature of the reaction is that in parallel to H3O+, HGul also catalyzes the formation and reverse hydrolytic processes of γ-HGul, similarly to other general acid catalysts.

Abstract  The ability of Thermus thermophilus HB8 to produce simultaneously two environmentally-friendly biodegradable products, polyhydroxyalkanoates (PHAs) and rhamnolipids (RLs), using either sodium gluconate or glucose as sole carbon source, was demonstrated. The utilization of sodium gluconate resulted in higher levels of PHAs and RLs production than when glucose was used as sole carbon source. The initial phosphate concentration (as PO43-) influences both PHAs and RLs productions that were increased during cultivation time. PHAs accumulation was enhanced (> 300 mg/L) after 72 h of cultivation in an initial [PO43-] of 25 mM, while RLs production (> 200 mg/L) was started after 35 h and continued until 72 h of cultivation, in a phosphate-limited medium containing initially 5 mM of [PO43-]. In addition, the combine effect of initial [PO43-] and cultivation time on biomass, PHAs and RLs production was evaluated from 2D contour plots. The results revealed that low initial phosphate concentrations (up to 5 mM) and long incubation time (72 h) promoted RLs biosynthesis while higher initial phosphate concentrations (up to 25 mM) where favorable for biomass and PHAs production. The molecular composition of the produced bio-products was identified. The accumulated PHAs were co-polymers which mainly consisted of 3-hydroxydecanoate (3HD) as resulted by gas chromatography (GC) analysis. The secreted RLs were extracted and their total mixture contained both mono- and di- RLs identified by thin-layer chromatography (TLC). Moreover, the molecular composition of the produced RLs characterized in details by LC-MS analysis showed a plethora of diversity including mono-, and di-RLs, di-rhamno-monolipidic congeners differing in the length of the lipidic chain, which additionally were found to be saturated or unsaturated in some cases.

Abstract  The biosynthesis of polyhydroxyalkanoates (PHAs) was studied, for the first time, in the thermophilic bacterium Thermus thermophilus. Using sodium gluconate (1.5% w/v) or sodium octanoate (10 mM) as sole carbon sources, PHAs were accumulated to approximately 35 or 40% of the cellular dry weight, respectively. Gas chromatographic analysis of PHA isolated from gluconate-grown cells showed that the polyester (M-w:480,000 g. mol(-1)) was mainly composed of 3-hydroxydecanoate (3HD) with a molar fraction of 64%. In addition, 3-hydroxyoctanoate (3HO), 3-hydroxyvalerate (3HV) and 3-hydroxybutyrate (3HB) occurred as constituents. In contrast, the polyester (M-w:391,000 g mol(-1)) from octanoate-grown cells was composed of 24.5 mol% 3HB, 5.4 mol% 3HO, 12.3 mol% 3-hydroxynonanoate (3HN), 14.6 mol% 3HD, 35.4 mol% 3-hydroxyundecanoate (3HUD) and 7.8 mol% 3-hydroxydodecanoate (3HDD). Activities of PHA synthase, a beta-ketothiolase and an NADPH-dependent reductase were detected in the soluble cytosolic fraction obtained from gluconate-grown cells of T. thermophilus. The soluble PHA synthase was purified 4271-fold with 8.5% recovery from gluconate-grown cells, presenting a K-m of 0.25 mM for 3HB-CoA. The optimal temperature of PHA synthase activity was about 70degreesC and acts optimally at pH near 7.3. PHA synthase activity was inhibited 50% with 25 muM CoA and lost all of its activity when it was treated with alkaline phosphatase. T. thermophilus PHA synthase, in contrary to other reported PHA synthases did not exhibit a lag phase on its kinetics, when low concentration of the enzyme was used. Incubation of PHA synthase with 1 mM N-ethyl-maleimide inhibits the enzyme 56%, indicating that cysteine might be involved in the catalytic site of the enzyme. Acetyl phosphate (10 mM) activated both the native and the dephosphorylated enzyme. A major protein (55 kDa) was detected by SDS-PAGE. When a partially purified preparation was analyzed on native PAGE the major band exhibiting PHA synthase activity was eluted from the gel and analyzed further on SDS-PAGE, presenting the first purification of a PHA synthase from a thermophilic microorganism.