Starter cultures growth media

Batch cultivation of P. mendocina KRl was carried out in 2 x 2 L centre column Erlenmeyer flasks. Each flask contained stock solution 1 (8 mL) and deionized water (390 mL). This solution was autoclaved and cooled before adding 400 /iL stock solution 2,400 uL stock solution 3 and 400 pL stock solution 4. Toluene (600 /iL) was added to the centre column. Overnight starter cultures were used to inoculate (2% v/v) the growth medium. Cultures were incubated at 30 °C shaking at 200 rpm. 

Figure 3.13. Outline of the upstream processing stages involved in the production of a single batch of product. Initially, the contents of a single ampoule of the working cell bank (a) is used to inoculate a few hundred ml of medium (b). After growth, this lab-scale starter culture is used to inoculate several litres/tens of litres of medium present in a small bioreactor (c). This production scale starter culture is used to inoculate the production-scale bioreactor (d), which often contains several thousands/tens of thousands litres of medium. This process is equally applicable to prokaryotic or eukaryotic-based producer cell lines, although the bioreactor design, conditions of growth, etc. will differ in these two instances...

Successful cultivation of microorganisms for growth and identification requires use of various types of media, either liquid (referred to as hroths) or solid by inclusion of agar. For winemakers, a growth medium may he as simple as diluted sterile grape juice for the activation and expansion of yeast starter cultures or as complicated as that necessary to grow lactic acid bacteria. 

Alcohol used for drinks is made primarily from potatoes, cereals and molasses. Distiller s yeast, especially the top fermenting culture (cf. 20.3.2.1), is used for fermentation. Since the fermentation proceeds in an unsterilized mash and at elevated temperatures and since the growth of yeast occurs in mash acidified with lactic or sulfuric acid (pH 2.5-5.5), the yeast must be highly fermentative, tolerant of elevated temperatures (<43 °C) and resistant to acids and alcohol. In addition to saccharification by malt which contains mainly P-amylase, high-activity microbial a-amylases are also used. Molasses does not require saccharification. The saccharified mash is cooled to 30 C and then inoculated with a yeast starter which has been cultured on a sulfuric or lactic acid medium of the mash or directly with distiller s yeast. After 48h of fermentation, the ethanol present at 6-10% by volume in the mash is distilled off along with the other volatile constituents. This step and the following rectification of the crude alcohol are achieved by continuous processes. 

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