Fermentation gluconic acid

The reaction mechanisms in the fermentation of glucose to gluconic acid are ... 

Humid air with 02 is prepared for a gluconic acid fermentation. The humid air has been prepared by a special humidification chamber where 1.5 1/h of liquid water enters at the same... 

Different routes for converting biomass into chemicals are possible. Fermentation of starches or sugars yields ethanol, which can be converted into ethylene. Other chemicals that can be produced from ethanol are acetaldehyde and butadiene. Other fermentation routes yield acetone/butanol (e.g., in South Africa). Submerged aerobic fermentation leads to citric acid, gluconic acid and special polysaccharides, giving access to new biopolymers such as polyester from poly-lactic acid, or polyester with a bio-based polyol and fossil acid, e.g., biopolymers . 

Lactobionic acid. This derivative is produced by oxidation of the free carbonyl group of lactose (Figure 2.25), chemically (Pt, Pd or Bi), electro-lytically, enzymatically or by fermentation. Its lactone crystallizes readily. Lactobionic acid has found only limited application its lactone could be used as an acidogen but it is probably not cost-competitive with gluconic acid-<5-lactone. It is used in preservation solutions for organs prior to transplants. 

Acid production is a key feature in the manufacture of all cheese varieties -the pH decreases to about 5 ( 0.3, depending on variety) within 5-20h, at a rate depending on the variety (Figure 10.11). Acidification is normally achieved via the bacterial fermentation of lactose to lactic acid, although an acidogen, usually gluconic acid-<5-lactone, alone or in combination with acid, may be used in some cases, e.g. Mozzarella. 

On acidification to pH 4.6, the caseins coagulate, which is the principle used to manufacture of a family of cheeses which represent about 25% of total cheese consumption and are the principal cheeses in some countries (Appendix 10B). Acidification is traditionally and usually achieved by in situ fermentation of lactose by a Lactococcus starter but direct acidification by acid or acidogen (gluconic acid-d-lactone) is also practised. The principal... 

A mathematical model of the fermentation of the bacterium Pseudomonas ovalis, which produces gluconic acid, has been developed (Rai Constantinides, AIChE Symposium Series 69 No 132, 114, 1973). This model which describes the dynamics of the logarithmic growth phase is summarized as follows. 

Bacterium gluconicum,424,425 B. xiy/inum,405-407,424-428 other Bacterium species,427 and Pseudomonas species.428 This fermentation proceeds from D-glucose (8), to D-gluconic acid (86), to 82. 

The second procedure, and probably the more effective [if, as here, the desired product is L-xy/o-2-hexulosonic acid (28)], is based on simultaneous, fermentative oxidation of L-idonic acid (42) to 28, and fermentative decomposition of D-gluconic acid (86). Efforts directed toward the simultaneous oxidation of 42 and decomposition of D-gluconic acid will be summarized, as well as efforts made to convert 42 efficiently into 28 by fermentative oxidation. 

The production of substances that preserve the food from contamination or from oxidation is another important field of membrane bioreactor. For example, the production of high amounts of propionic acid, commonly used as antifungal substance, was carried out by a continuous stirred-tank reactor associated with ultrafiltration cell recycle and a nanofiltration membrane [51] or the production of gluconic acid by the use of glucose oxidase in a bioreactor using P E S membranes [52]. Lactic acid is widely used as an acidulant, flavor additive, and preservative in the food, pharmaceutical, leather, and textile industries. As an intermediate product in mammalian metabolism, L( +) lactic acid is more important in the food industry than the D(—) isomer. The performance of an improved fermentation system, that is, a membrane cell-recycle bioreactors MCRB was studied [53, 54], the maximum productivity of 31.5 g/Lh was recorded, 10 times greater than the counterpart of the batch-fed fermentation [54]. 

D-Gluconic acid (7) is produced at scale by the fermentative oxidation of D-glucose (3) with Acetobacter, Pseudomonas, or Penicillium sp. (Scheme 4.5).33 It is used as a processing aid. 

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