Growth medium carbon sources

Fermentation processes need several components as starting materials an inoculum, growth medium (carbon source such as carbohydrates and sugars, and nitrogen source such as ammonium salts), air/gas, and water. To have a successful fermentation, all these components have to be maintained as sterile to avoid contamination. 

Fermentation processes need several components as starting materials an inoculum, growth medium (carbon source... 

Further efficient fermentative methods for manufacture of riboflavin have been patented one is culturing C. famata by restricting the carbon source uptake rate, thereby restricting growth in a linear manner by restriction of a micronutrient. By this method, productivity was increased to >0.17 g riboflavin/L/h (63). The other method, using Bacillus subtilis AJ 12644 low in guanosine monophosphate hydrolase activity, yielded cmde riboflavin 0.9 g/ L/3 days, when cultured in a medium including soy protein, salts, and amino acids (64). 

As you might have already gathered, the majority of industrial fermentations are batch processes. In closed batch systems, the growth medium is inoculated with cells and growth and product formation is allowed to proceed until the required amount of conversion has taken place. After harvesting the culture the vessel is cleaned, sterilised and filled with fresh medium prior to inoculation. For some processes, addition of all the feedstock prior to inoculation, as is done in closed batch fermentations, is undesirable and it is preferable to incrementally add the carbon source as the fermentation proceeds. Such a process is known as fed-batch culture and the approach is often used to extend the lifetime of batch cultures and thus product yields fed-batch cultures are considered further in Section 2.7.4. 

In media selective for enterobacteria a surface-active agent is the main selector, whereas in staphylococcal medium sodium and lithium chlorides are the selectors staphylococci are tolerant of salt concentrations to around 7.5%. Mannitol salt, Baird-Parker (BP) and Vogel-Johnson (VJ) media are three examples of selective staphyloccocal media. Beside salt concentration the other principles are the use of a selective carbon source, mannitol or sodium pyruvate together with a buffer plus acid-base indicator for visualizing metabolic activity and, by inference, growth. BP medium also contains egg yolk the lecithin (phospholipid) in this is hydrolysed by staphylococcal (esterase) activity so that organisms are surrounded by a cleared zone in the otherwise opaque medium. The United States Pharmacopeia (1990) includes a test for staphylococci in pharmaceutical products, whereas the British Pharmacopoeia (1993) does not. 

Candida boidinii was cultured at pH 3.51, 5.49 and 7.01, respectively. Czapek s Dox medium with citrus pectin (GENU Pectin, Denmark), sodium pectate or citrus pectin with 20% of D-galactopyranuronic acid (Fluka, Switzerland) as a carbon source were used. The growth curves were performed by measuring the optical density (OD) at 660 nm. 

The suitability of a bacterium for poly(3HB) production on an industrial scale depends on many different factors such as stability and safety of the organism, growth and accumulation rates, achievable cell densities and poly(3HB) contents, extractability of the polymer, molecular weights of accumulated poly(3HB), range of utilizable carbon sources, costs of the carbon source and the other components of the medium, and occurrence of byproducts [11]. 

Although plant cell culture is not as cost effective as plant cultivation in the open field, it will become an economical process if higher protein yields can be achieved [58]. The cultivation medium of plants is chemically defined, consisting of a carbon source, minerals, vitamins and phytohormones [69]. Furthermore, it is protein-free and relatively inexpensive. In contrast, animal cells often require complex supplements such as fetal calf serum and/or expensive growth factors, although serum-free cultivation is possible in case of Chinese hamster ovary (CHO) cells [70]. 

For biodegradation to occur, everything that bacteria require for growth and reproduction must be available in the microenvironment in the immediate vicinity of the bacterium. The soil-aquifer system must provide water, attachment medium, a source of carbon, gas exchange, electron acceptor compounds, and nutrients. If any of the required items is not available, bacterial functions will be reduced or cease. 

Table III). Pseudomonas was capable of using diflubenzuron as a sole carbon source, but bacterial growth was greatly accelerated when the medium was supplemented with acetate. 

Fig. 18.2 Growth and P(3HB-co-4HB) accumulation of Cupriavidus sp. USMAA1020 on MSM containing y-butyrolactone as the sole carbon source in a one-step cultivation process. The one-step culture medium is same as two-step culture medium but contains 1.1 g/L (NH )2SO as nitrogen...

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