Oxalic Acid Production by Aspergillus niger: Influence of Hydrogen Ion Concentration and Nitrogen Source

A medium has been developed that permits the viable count of milk bacteria to be combined with the determination of biochemical properties likely to be important in milk itself. This has involved the modification of standard glucose-tryptone skim-milk agar by incorporation of two indicators to detect alkali as well as acid production, substitution of lactose for glucose, and increasing the quantity of skim milk for the detection of proteolysis and casein precipitation. The medium has proved particularly valuable in the study of the thermoduric flora of pasteurized milk. The phenomenon of casein precipitation is, however, less reliably determined than are changes in hydrogen-ion concentration and proteolysis.

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Effect of some physiological factors on citric acidproduction bythreeisolates ofAspergillus niger acid - hydrolyzed sawdust as a carbon source

Innovaciencia Facultad de Ciencias Exactas Físicas y Naturales ◽

10.15649/2346075x.477 ◽

2018 ◽

Vol 6 (2) ◽

pp. 1-9

Author(s):

Muna, B. Abdulazeez ◽

Mustafa M. Haider

Keyword(s):

Citric Acid ◽

Aspergillus Niger ◽

Carbon Source ◽

Acid Production ◽

Large Scale ◽

Nitrogen Concentration ◽

Tricarboxylic Acid ◽

Ion Concentration ◽

Citric Acid Production ◽

Hydrogen Ion Concentration

Introduction: Citric acid (2-hydroxy-propane-1, 2, 3-tricarboxylic acid) was first isolated from lemon juice in 1784. It is a primary metabolic product which is formed in the tricarboxylic acid (Krebs) cycle. It is estimated that the market value of citric acid will exceed two billion dollars in 2019. About 70% of total citric acid produced globally is utilized in food industry, while about 12% is utilized in pharmaceuticals and cosmetic industries and the remainder in other industrial purposes. The industrial production of citric acid is undertaken by fermentation process in the presence of filamentous fungi for large scale of production. Aspergillus niger is the most efficient fungus due to its ability to produce more citric acid per unit time and ferment different inexpensive raw materials. Materials and Methods: Three isolates of the fungus Aspergillus niger (An1, An2, An3) were used throughout this study using different carbon source concentration in the form of sawdust acid hydrolysis supplemented with different concentration of (NH4)2H2SO4 as a nitrogen source. The effect of hydrogen ion concentration and addition of methanol to the fermentation medium was also investigated. Results and Discussion: The results indicated that the optimization of carbon and nitrogen concentration had stimulatingeffect on citric acid production by the three used isolates. Moreover, addition of methanol at concentration of 1% at pH of 3.5 highly increased citric acid production. Conclusion: we concluded that the agriculture waste was a favorable substrate for the production of citric acid especially it is cost effective and easily obtainable.

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Effect of glucose and inosine triphosphate on seasonal variation of gastric acid production in Rana pipiens

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1959.196.5.975 ◽

1959 ◽

Vol 196 (5) ◽

pp. 975-978 ◽

Cited By ~ 1

Author(s):

Sherwin Mizell

Keyword(s):

Seasonal Variation ◽

Gastric Acid ◽

Acid Production ◽

Rana Pipiens ◽

Hydrogen Ion ◽

Ion Concentration ◽

Hydrogen Ion Concentration ◽

Total Chloride ◽

Effect Of Glucose

The production of acid in vitro by the gastric mucosa of 375 Rana pipiens was studied over a period of 13 months. The frogs were kept at 21°C and histamine was used to induce secretion. Four conditions were studied: a) control, no substrate added to the nutrient solution; b) 10 mm glucose added; c) 0.6 µm inosine triphosphate (ITP) added and d) 10 mm glucose and 0.6 µm ITP added. For each mucosa the change in hydrogen ion concentration (ΔpH), titrable acidity and total chloride produced were measured. The results indicate that the seasonal variation in gastric acid production is due, in part, to a variation in the availability of substrate normally present.

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The adsorption of substances by fuller's earth

Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character ◽

10.1098/rspb.1931.0029 ◽

1931 ◽

Vol 108 (755) ◽

pp. 174-174

Keyword(s):

Oxalic Acid ◽

Acid Solution ◽

Hydrogen Ion ◽

Ion Concentration ◽

Rapid Rise ◽

Hydrogen Ion Concentration ◽

Maximum Value ◽

Rapid Fall ◽

Fuller’S Earth

Propionic and hexoic acids are not adsorbed by fuller's earth to any extent at any p H . Oxalic acid is adsorbed in solutions more alkaline than p H 1.5. The adsorption rises to a maximum at about p H 4 and then falls off very gradually with increasing alkalinity. At p H 12 the adsorption is about three-quarters of its maximum value. The adsorption of n -propylamine and n -butylamine is influenced by acidity in almost exactly the same way. In both cases the adsorption rises from a vanishingly small value in very acid solution to about p H 4.5. From p H 4.5 to about p H 8 the adsorption is almost independent of the hydrogen-ion concentration. In solution more alkaline than p H 9.5 there is a very rapid rise in the adsorption to a maximum at p H 11, which is immediately followed by a rapid fall to a vanishingly small value at p H 13.

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SOURCE AND SIGNIFICANCE OF STREPTOCOCCI IN MARKET MILK

Journal of Experimental Medicine ◽

10.1084/jem.31.4.347 ◽

1920 ◽

Vol 31 (4) ◽

pp. 347-361 ◽

Cited By ~ 4

Author(s):

F. S. Jones

Keyword(s):

Acid Production ◽

Great Frequency ◽

Hydrogen Ion ◽

Ion Concentration ◽

Blood Agar ◽

Hydrogen Ion Concentration ◽

Fecal Streptococci ◽

Principal Source ◽

Horse Blood

The principal source of streptococci in milk is the cow's udder. The udder streptococci fall into two broad groups; those of the larger group agree in cultural characters and agglutination affinities with mastitis streptococci; the smaller group is composed of low acid-producing streptococci. The streptococci of the latter group produce clear zones of hemolysis about surface and deep colonies in horse blood agar plates. They attack dextrose, lactose, saccharose, and maltose, but do not ferment raffinose, inulin, mannite, or salicin. Acid production in dextrose by the members of this group is about the same as that produced by human streptococci under the same conditions. The limiting hydrogen ion concentration for these pleomorphic udder streptococci in dextrose serum bouillon is within the limits of the limiting hydrogen ion concentration observed by Avery and Cullen for human streptococci. All the streptococci from the vagina, saliva, skin, and feces have been non-hemolytic. Those from the saliva form a heterogeneous aggregation in which individuals fermenting raffinose, inulin, and mannite predominate. From the skin a characteristic streptococcus has been found. It produces acid in dextrose, lactose, saccharose, maltose, raffinose, mannite, and salicin, but fails to acidulate media containing inulin. The fecal streptococci are characterized by the formation of large amounts of acid in dextrose, lactose, saccharose, maltose, raffinose, inulin, and salicin. Mannite is not fermented. Neither the fecal nor the skin streptococci have been isolated from the bottled milk with any great frequency.

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