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Gluconic Acid (gluconic + acid)

Distribution by Scientific Domains

Life Sciences	62%
Chemistry	37%

Selected Abstracts

A Novel Synthesis of 2-Amino-2-deoxy- D -gluconic Acid and Its Complexation with Cu(II) in Alkaline Medium

CHINESE JOURNAL OF CHEMISTRY, Issue 10 2006
Wen-Xiu Gu
Abstract A novel synthesis of the functional carbohydrate 2-amino-2-deoxy- D -gluconic acid was introduced and its complex formation with Cu(II) was investigated to obtain the stability constant for its further applications to the food and pharmaceutical industries. The equilibrium was investigated by spectrophotometric measurements and processed by dual-series linear regression method. Results:the yield of 2-amino-2-deoxy- D -gluconic acid is 70%. The complexation molar ratio is 1:2, the molar apsorptivity of the complex is 39.906 L·mol,1·cm,1 at 630 nm, and the stability constant ,nis 6.24×105. [source]

Inactivation of pqq genes of Enterobacter intermedium 60-2G reduces antifungal activity and induction of systemic resistance

FEMS MICROBIOLOGY LETTERS, Issue 1 2008
Song Hee Han
Abstract Enterobacter intermedium 60-2G, a phosphate solubilizing bacterium, has the ability to induce systemic resistance in plants against soft rot pathogen Erwinia carotovora. Glucose dehydrogenase, an enzyme that utilizes pyrroloquinoline quinone (PQQ) as a cofactor, is required for the synthesis of gluconic acid by E. intermedium 60-2G. Here, we report that the pqqA and pqqB genes are required for phosphate solubilization and induced systemic resistance against a soft rot pathogen in tobacco. Mutations in either the pqqA or pqqB gene abolished the production of 2-ketogluconic acid and eliminated the ability of E. intermedium to solubilize hydroxyapatite. Addition of gluconic acid to the growth media restored the ability of the pqqA mutant to produce 2-ketogluconic acid. Interestingly, both pqqA and pqqB mutants of E. intermedium lost their ability to inhibit the growth of the rice pathogen Magnaporthe grisea KI-409. Additionally, induced systemic resistance against the soft rot pathogen was attenuated in the pqq mutants. These functions were restored by complementation with the wild-type pqq gene cluster. Our findings suggest that PQQ plays an important function in beneficial traits including phosphate solubilization, antifungal activity, and induced systemic resistance of E. intermedium, possibly by acting as a cofactor for several enzymes including glucose dehydrogenase. [source]

Quality of thawed deepwater pink shrimp (Parapenaeus longirostris) treated with melanosis-inhibiting formulations during chilled storage

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2007
Maria Elvira López-Caballero
Summary This work investigates how the treatment of thawed deepwater pink shrimp (Parapenaeus longirostris) with several melanosis-inhibiting formulations, affects the quality of the shrimp during chilled storage. Formulations were as follows: a formulation containing 4-hexylresorcinol (0.1 and 0.05%), in combination with organic acids and chelating agents, a commercial formula based on sulphites, and a mixture of gluconic acid and commercial sulphites. No noticeable differences were observed for both trimethylamine and total volatile bases during chilled storage. pH evolution was irrespective of the treatment condition. Microbial load enlarged after the sixth day of chilled storage. Higher total bacteria counts were associated with the control and sulphite treatment conditions, while lactic acid bacteria growth seemed to be favoured under formulations based on 4-hexylresorcinol. The appearance of melanosis occurred more rapidly in control shrimp or in shrimp treated with commercial sulphites. 4-hexylresorcinol formulations preserved the quality of thawed shrimp and could replace traditional sulphites. [source]

Gluconic acid production by Aspergillus terreus

LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2010
C. Dowdells
Abstract Aim:,Aspergillus terreus produces itaconic acid at low pH but lovastatin and other secondary metabolites at higher pH in the fermentation. The utilization of glucose as a carbon substrate was investigated for secondary metabolite production by A. terreus. Methods and Results:, With a starting pH of 6·5, glucose was rapidly metabolized to gluconic acid by the wild-type strain and by transformants harbouring Aspergillus niger genes encoding 6-phosphofructo-1-kinases with superior kinetic and regulatory properties for bioproduction of metabolites from glucose. On exhaustion of the glucose in batch fermentations, the accumulated gluconic acid was utilized as a carbon source. Conclusions:, A novel pathway of glucose catabolism was demonstrated in A. terreus, a species whose wild type is, without any strain development, capable of producing gluconic acid at high molar conversion efficiency (up to 0·7 mol mol,1 glucose consumed). Significance and Impact of the Study:,Aspergillus terreus is a potential novel producer organism for gluconic acid, a compound with many uses as a bulk chemical. With a new knowledge of glucose catabolism by A. terreus, fermentation strategies for secondary metabolite production can be devised with glucose feeding using feedback regulation by pH. [source]

A multikinetic model approach to predict gluconic acid production in an airlift bioreactor

BIOTECHNOLOGY JOURNAL, Issue 5 2007
Mukesh Mayani
Abstract This paper uses a multikinetic approach to predict gluconic acid (GA) production performance in a 4.5 L airlift bioreactor (ALBR). The mathematical model consists of a set of simultaneous firstorder ordinary differential equations obtained from material balances of cell biomass, GA, glucose, and dissolved oxygen. Multikinetic models, namely, logistic and contois equations constitute kinetic part of the main model. The main model also takes into account the hydrodynamic and mass transfer parameters. These equations were solved using ODE solver of MATLAB v6.5 software. The mathematical model was validated with the experimental data available in the literature and is used to predict the effect of change in initial biomass and air sparging rate on the GA production. It is concluded that the mathematical model incorporated with multikinetic approach would be more efficient to predict the change in operating parameters on overall bioprocess of GA production in an ALBR. [source]

Metabolic profiling as a tool for understanding defense response of Taxus Cuspidata cells to shear stress

BIOTECHNOLOGY PROGRESS, Issue 5 2009
Pei-Pei Han
Abstract To obtain a better understanding of responsive mechanism of plant cells in response to hydrodynamic mechanical stress, a metabolic profiling approach was used to profile metabolite changes of Taxus cuspidata cells under laminar shear stress. A total of 65 intracellular metabolites were identified and quantified, using gas chromatography coupled to time-of-flight mass spectrometry. Potential biomarkers were found by the principal component analysis as well as partial least squares combined with variable influence in the projection. Trehalose, sorbitol, ascorbate, sucrose, and gluconic acid were mainly responsible for the discrimination between shear stress induced cells and control cells. Further analysis by mapping measured metabolite concentrations onto the metabolic network revealed that shear stress imposed restrictions on primary metabolic pathways by inhibiting tricarboxylic acid cycle, glycolysis, and N metabolism. To adapt to the shear condition, cells responded by starting defensive programs. These defensive programs included coinduction of glycolysis and sucrose metabolism, accumulation of compatible solutes, and antioxidative strategy. A strategy of defense mechanisms at the level of metabolites for T. cuspidata cells when challenged with the shear stress was proposed. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]