Fermentation culture development

More recently, a recombinant non-infec-tious subunit viral vaccine derived from the hepatitis B surface antigen (Recombi-vax HB) has been developed. The antigen is produced in fermentation cultures of Saccharomyces cerevisiae, and is therefore free from human blood products. Hepatitis B is an inflammation of the liver caused by the hepatitis B virus, and can be very serious or even fatal. The virus is usually spread by contact with infected blood, though an infection can be prevented by vaccination. The vaccine is highly immunogenic, well-tolerated, and possesses an excellent protective efficacy that leads to immunity for 10 years. 

The second fermentation was developed using yeast strains, such as Yarrowia lipolytica ATCC 34088, that has limited P-oxidation abilities. The recovered hydroxy fatty acids were fed into a new fermenter and sterilized with other ingredients before inoculation with Y. lipolytica culture. Y. lipolytica converted C-18 10-hydroxy fatty acids to the corresponding lactone intermediates, 4-hydroxy C12 fatty acids via a limited P-oxidation. The fermentation was usually terminated at the point of a maximum accumulation of lactone intermediates, at the concentration of 5 g/L in the fermentation broth. After the fermentation process was complete, the lactone intermediates were lactonized at a pH in the range of 3-5 and at a temperature of >100°C. The resulting lactones were recovered and purified from the fermentation broth by solvent extraction followed by fractional distillation. 

In order to reduce the overall cost, there has been many fermentation techniques developed to produce PHAs with high productivity and high yield such as batch, fed-batch and continuous cultivations [5, 13]. Two stage fermentation is the most common and highly productive method to generate high density culture as well as increased amount of PHAs. 

Holzapfel, H. W. (2002). Appropriate starter culture technologies for small-scale fermentation in developing countries. International Journal of Food Microbiology, 75,197-212. 

The use of fermentation to preserve and improve the properties of food has a long history. For example, milk has been preserved by fermentation for at least seven millennia (Dunne et ah, 2012). Initially, fermentation was a spontaneous process, probably with mixed results, and it was quickly learned that inoculation of the material to be fermented with a suitable inoculum would increase the likelihood of success. Traditionally, this was done by using part of a previous fermentation as an inoculum, but as microbiological knowledge increased, inoculation with specifically prepared fermentation starter cultures developed (Hpier et al., 2010). This in turn gave a better control of the fermentation process and allowed for the development of new products with novel properties. This is well illustrated in the dairy industry, where a diversity of bacterial species is used to manufacture a large variety of fermented dairy products (Table 10.1). 

An enzyme being complementary to a nitrile hydratase, which catalyzes water addition to a nitrile, is an aldoxime dehydratase as a biocatalyst being capable to eliminate water from an oxime moiety, thus leading to the formation of a nitrile. Such aldoxime dehydratases are also synthetically useful as demonstrated by the Asano group who applied an aldoxime dehydratase from a Bacillus sp., for example, for the dehydration of Z-phenylacetaldoxime to produce phenylacetonitrile [37-41], For this substrate, the overexpressed aldoxime dehydratase showed a high activity of 14000U/1 of fermentation culture of a developed recombinant E. coli strain [3 . In addition, numerous other transformations of aromatic and aliphatic aldehydes have been reported [37 1],... 

In the 1950s, a group of coryneform bacteria which accumulate a large amount of L-glutamic acid in the culture medium were isolated (21). The use of mutant derivatives of these bacteria offered a new fermentation process for the production of many other kinds of amino acids (22). The amino acids which are produced by this method are mostiy of the T.-form, and the desired amino acid is singly accumulated. Therefore, it is very easy to isolate it from the culture broth. Rapid development of fermentative production and en2ymatic production have contributed to the lower costs of many protein amino acids and to their availabiUty in many fields as economical raw materials. 

L-Sorhose to 2-KGA Fermentation. In China, a variant of the Reichstein-Grbssner synthesis has been developed on an industrial scale (see Fig. 5). L-Sorbose is oxidized direcdy to 2-ketogulonic acid (2-KGA) (24) in a mixed culture fermentation step (48). Acid-catalyzed lactonization and enolization of 2-KGA produces L-ascorbic acid (1). 

The function of Jisper Uis fermentation appears to be primarily the breakdown of protein and polysaccharides by secreted proteases and amylases. Replacement oiPispergillis by chemical or enzymatic hydrolysis has no major impact on the organoleptic properties of the sauce. Likewise, inoculation with a pure culture of Ixictobacillus delbrueckii to carry out the acetic acid fermentation produces a normal product. The S. rouxii and Toru/opsis yeasts, however, are specifically required for proper flavor development. 

Superior penicillin producing cultures ate capable of producing in excess of 30 mg/mL of penicillin G (154). Cephalosporin producing strains, however, generally grow poorly and cephalosporin C production is not as efficient as is that of penicillin. Factors such as strain maintenance, strain improvement, fermentation development, inoculum preparation, and fermentation equipment requkements ate discussed in the hterature (3,154). 

Sour mash fermentations must have not less than 20% stiUage added back (backset) to the mash and be fermented for not less than 72 hours. A lactic culture is used and is permitted to develop for a period of not less than six hours. 

As described in U.S. Patent 2,929,763, methandrostenolone may be made by a fermentation route. 2 g of sodium nitrate, 1 g of primary potassium orthophosphate, 0.5 g of magnesium sulfate heptahydrate, 0.5 g of potassium chloride, 50 g of glucose and 1 g of Difco yeast extract are dissolved in one liter of tap water, brought to pH 5 by addition of a sodium hydroxide solution and sterilized. The resulting nutrient solution is inoculated with 50 cc of a 4-day-old shaking culture of Didyniel/a lycopersici and shaken for 48 hours at 27 C, whereby the culture becomes well developed. 

Historically the production of titrate has been an important development in the pioneering of fermenter technology. It was shown back in 1893 by Wehmer that a fungus, Citromyces (now reclassified as a Penicilliutn spp.) would accumulate citric add in liquid culture. Wehmer in fact tried to scale up the process to an industrial level but there were two main problems. Firstly, the duration of the process under his conditions took far too long of the order of several weeks. Secondly, a problem was caused by Wehmer s incorrect belief that citric add only accumulated around neutral pH and lengthy incubation at this pH inevitably leads to contamination. 

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