Critical analysis of the effect of metal ions on gluconic acid production by Aspergillus niger using a treated Indian cane molasses
TL;DR: The yield of gluconic acid was influenced more by a combination of metal ions rather than individual ions, and potassium ferrocyanide treatment gave the most promising results compared to other treatment techniques.
Abstract: Gluconic acid fermentation by Aspergillus niger has been investigated using untreated and treated Indian cane molasses. The yield of gluconic acid was found to be reduced using an untreated molasses medium compared to a defined medium. Hence, molasses was subjected to various pretreatment techniques. Pretreatment reduced the levels of various cations and anions. As the synthesis of gluconic acid has been observed to be influenced more by cations than anions, the effect of various metal ions, viz., copper, iron, zinc, manganese, calcium, and magnesium on the yield of gluconic acid has been critically examined in both untreated and treated cane molasses. These results have been compared with a defined medium. The yield of gluconic acid was influenced more by a combination of metal ions rather than individual ions. Potassium ferrocyanide treatment gave the most promising results compared to other treatment techniques.
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TL;DR: A comparative analysis of yield has revealed that calcium alginate entrapment was the most suitable technique as it had given the maximum product yield (0.40 g gluconic acid/g total reducing sugar supplied).
Abstract: To compare the efficiency of various whole cell immobilization techniques for the production of gluconic acid by Aspergillus niger were investigated using potassium ferrocyanide-treated cane molasses as the substrate. The techniques followed were:
(1)
Calcium alginate entrapment,
(2)
cross-linking with glutaraldehyde after cell permeabilization with (a) acetone, (b) toluene and (c) isopropanol and
(3)
development of granular catalyst.
13 citations
TL;DR: In this paper, a simple model of Luedeking-piret, logistic, and Luedeling-Piret-like equations were proposed for gluconic acid production, cell growth, and breadfruit hydrolysate consumption respectively.
Abstract: The kinetics of gluconic acid production by Aspergillus niger (A. niger) using breadfruit hydrolysate was studied in a batch bioreactor. A simple model of Luedeking–Piret, logistic, and Luedeking–Piret-like equations were proposed for gluconic acid production, cell growth, and breadfruit hydrolysate consumption respectively. The maximum gluconic acid concentration (Pt) of 109.95 g/L with 0.967 g/g process yield (88.70%) was obtained for the medium containing 120 g/l breadfruit hydrolysate at 2 vvm aeration rate. For the same conditions, the biomass concentration and maximum specific growth were obtained as 24.3 g/L and 0.018 hr−1 respectively. The models proposed for the gluconic acid production was sufficiently satisfactory, since the theoretical values of Pt (100.94 g/L) and biomass concentration (23.43 g/L) obtained from the models were almost the same with the experimental values. The model for the breadfruit hydrolysate utilization gave R2 and Adj. R2 of above 0.840 and 0.660 respectively; an indication that the model is suitable for the production of gluconic acid. Therefore, the concentration of initial breadfruit hydrolysate as substrate and aeration rate have shown significant effect on gluconic acid production and A. niger accumulation. The evaluation of the models showed that the gluconic acid production was growth-associated.
Practical applications
Breadfruits, a perishable fruit has been abundantly found in Ile-Ife, Nigeria where 50% of it perishes due to its short shelf-life. This study therefore provides alternative use for breadfruit, in order to reduce its wastage. Furthermore, the growing demand of gluconic acid can be met through the use of this cheap and available breadfruit. The findings in this study can be employed to develop a bioreactor for fermentation of breadfruit hydrolysate to produce gluconic acid.
10 citations
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TL;DR: Gluconic acid is a multifunctional organic acid used as a bulk chemical in the food, feed, pharmaceutical, textile, metallurgy, detergent, paper, and construction industries.
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.
9 citations
01 Jan 2022
TL;DR: In this article , a review of microbial sources and production methods of different organic acids (citric acid, gluconic acid, fumaric acid and lactic acid) used mainly in the food industry is presented.
Abstract: Microorganisms play a prominent role in generating a variety of products that have applications in different areas, such as energy, food, chemicals, diagnostics, and pharmaceuticals. They are the source of enzymes, organic acids, amino acids, antibiotics, vitamins, single-cell proteins, and other commodity chemicals of commercial importance. The advances in microbial fermentation techniques have led to the development of ecofriendly processes to replace some of the conventional chemical processes. Organic acids are traditional products of food technology and biotechnology. At the same time, organic acids are among the most promising future products of industrial microbiology, owing to their possible use as building block chemicals. The production of organic acid through microbial fermentations using less expensive raw material is also one of the major achievements of industrial microbiology. This review mainly focuses on the microbial sources and production methods of different organic acids (citric acid, gluconic acid, fumaric acid, and lactic acid) used mainly in the food industry.
6 citations
TL;DR: In this article, the batch production of gluconic acid in the presence of glucose, sucrose and molasses was investigated using free mycelia of Aspergillus foetidus NRRL 337 in shake flasks.
Abstract: The batch production of gluconic acid in the presence of glucose, sucrose and molasses was investigated using free mycelia of Aspergillus foetidus NRRL 337 in shake flasks. Eight growth parameters were chosen as independent variables. The temperature, pH, substrate type and initial concentrations, inoculum percentage and shake rate directly affected the specific microorganism growth and gluconic acid production rates. The optimum temperature and initial pH values were found to be 33 °C and five to six, respectively. The maximum specific growth and gluconic acid production rates were established as 57 g/dm 3 of glucose, 75 g/dm 3 of sucrose and 150 g/dm 3 of molasses. The optimum values of the shake rate, inoculum percentage and initial ammonium nitrate concentration were determined as 100 l/min, 0.5% and 1.5 g/dm 3 , respectively. The maximum gluconic acid concentrations corresponding to these initial substrate concentrations were observed to be 8.3 g/dm 3 , 17.4 g/dm 3 and 37.0 g/dm 3 , respectively. The optimum specific microbial growth and gluconic acid production rates were found as 0.0145 l/h and 0.0375 g/g x h, respectively, for the fermentation conditions of S Go = 57 g/dm 3 , T = 28 °C, initial pH = 6.5, N = 84 1/min, A = 0.5 g/dm 3 and I= 0.5%.
4 citations
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TL;DR: Determinations of activity at substrate and effector concentrations resembling the conditions that occur in vivo support the hypothesis that the apparent insensitivity of the enzyme to citrate during the accumulation of citric acid in the fungus is due to counteraction of citrate inhibition by NH4+.
Abstract: Phosphofructokinase (EC 2.7.1.11) from a citric acid-producing strain of Aspergillus niger was partially purified by the application of affinity chromatography on Blue Dextran--Sepharose and the use of fructose 6-phosphate and glycerol as stabilizers in the working buffer. The resulting preparation was still impure, but free of enzyme activities interfering with kinetic investigations. Kinetic studies showed that the enzyme exhibits high co-operativity with fructose 6-phosphate, but shows Michaelis--Menten kinetics with ATP, which inhibits at concentrations higher than those for maximal activity. Citrate and phosphoenolpyruvate inhibit the enzyme; citrate increases the substrate (fructose 6-phosphate) concentration for half-maximal velocity, [S]0.5, and the Hill coefficient, h. The inhibition by citrate is counteracted by NH4+, AMP and phosphate. Among univalent cations tested only NH4+ activates by decreasing the [S]0.5 for fructose 6-phosphate and h, but has no effect on Vmax. AMP and ADP activate at low and inhibit at high concentrations of fructose 6-phosphate, thereby decreasing the [S]0.5 for fructose 6-phosphate. Phosphate has no effect in the absence of citrate. The results indicate that phosphofructokinase from A. niger is a distinct species of this enzyme, with some properties similar to those of the yeast enzyme and in some other properties resembling the mammalian enzyme. The results of determinations of activity at substrate and effector concentrations resembling the conditions that occur in vivo support the hypothesis that the apparent insensitivity of the enzyme to citrate during the accumulation of citric acid in the fungus is due to counteraction of citrate inhibition by NH4+.
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"Critical analysis of the effect of ..." refers methods in this paper
...Total reducing sugars (TRS) were determined by the DNS method [8] while gluconic acid and glucono-3-1actone were estimated by the hydroxamate method [ 9 ]....
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TL;DR: Free amino acid pools have been investigated in a citric acid accumulating strain of Aspergillus niger during batch growth under manganese sufficient and deficient conditions by means of an improved chromatographic method and it was observed that theManganese deficient mycelia excreted high amounts of all amino acids suggesting that manganes deficiency may also affect membrane permeability.
Abstract: Free amino acid pools have been investigated in a citric acid accumulating strain of Aspergillus niger during batch growth under manganese sufficient and deficient conditions by means of an improved chromatographic method. Studies on the mycelial content of several nitrogenous compounds under manganese sufficient and deficient conditions showed that manganese deficiency resulted in lower amino acid pool sizes during trophophase and considerable accumulation during idiophase, and in a reduction of the protein and nucleic acid contents. Addition of cycloheximide to mycelia grown with sufficient manganese also caused an elevation of free amino acid pool sizes, thus indicating that impairment of protein synthesis by manganese deficiency is responsible for the observed rise in amino acid concentration. Furthermore it was observed that the manganese deficient mycelia excreted high amounts of all amino acids suggesting that manganese deficiency may also affect membrane permeability.
74 citations
59 citations