Batch culture technique

Fermentation Technique. A human batch culture technique was used to measure in vitro fermentability of the samples (11). The technique was developed to utilize microflora present in human fecal matter. Maintenance of an anaerobic environment during collecting, processing and inoculating was important. The use of a modified camping toilet allowed collection while maintaining... 

In a study reported by Doi and co-workers [5], a fed-batch culture technique was applied for copolymer production using Alcaligenes eutrophus in which fructose and ammonium sulfate were fed at a rate of 0.76 and 0.15 g/h respectively. This feeding was then stopped and followed by pentanoic acid feeding at a rate of 0.6 g/h. At the end of the fermentation, 59 mol% of a 3-hydroxyvalerate (3HV) monomer was obtained the cell dry weight (CDW) and PHA content produced was 6.4 g/1 and 65 wt%, respectively. The periodic addition of methanol and n-amyl alcohol under nitrogen limitation to a culture of Paracoccus denitrificans in 3 1 fed-batch cultures resulted in the production of the poly[3-hydroxybutyrate (3HB)-co-3HV] copolymer. About 26% (w/w) containing 60 mol% of the 3HV monomer was obtained after 138 h [6]. 

Figure 2.4. Batch culture technique outline procedure.

This is the simplest biotransformation procedure it is based on conventional fermentation practices (see Appendix A). Batch-grown cultures inoculated in conical flasks (50-2,000 ml) are the norm for small-scale bioconversion purposes. In the batch culture technique (Figure 2.4), a pure... 

Fed-batch culture A cell cultivation technique in which one or more nutrients are supplied to the bioreactor in a given sequence during the growth or bioconversion process while the products remain in the vessel until the end of the run. 

The use of stirred fermenters with automatic control of the culture environment is the most suitable technique to evaluate bacterial or fungal kinetics. Cultures can be operated in discontinuous mode (batch cultures). 

Despite this area s promise there are some obstacles and limitations that must be solved, or at least considered, as plant-based proteins move toward the marketplace. The most intrinsic drawback for protein production in plants is time. When a protein is expressed in a whole plant, its production is linked directly to the development of that plant, often from seedling (or plantlet) to mature plant. In cell culture techniques, where cells are growing at maximal rates in an artificial environment, the time scale for producing a batch of protein is on the... 

Research with anaerobic cultures can be in batch or continuous culture. Fed-batch anaerobic reactors are not known to us but may very well be feasible. A reliable technique for batch cultures uses serum bottles sealed with butyl rubber stoppers and crimp sealed with an aluminum cap. Anaerobic microorganisms in batch flasks are mainly cultured by Hungate s methods [7] that are widely accepted in the research community. We will not describe these techniques but will focus on the different continuous culture apparatuses that have been developed over the years. 

Culture techniques can be classified into batch, fed-batch, and continuous operation (Table 2). In batch processes, all the nutrients required for cell growth and product formation are present in the medium prior to cultivation. Oxygen is supplied by aeration. The cessation of growth reflects the exhaustion of the limiting substrate in the medium. For fed-batch processes, the usual fed-batch and the repeated fed-batch operations are listed in Table 2. 

In spite of the mentioned drawbacks of traditional in vitro batch cell culture techniques, these are still the main tools used to study cellular functions, basically, because corresponding experiments in animals are time consuming, expensive and nowadays considered unethical. It would be. 

Perfusion cell culture (in suspension) is a proven method for the manufacture of MAbs and recombinant proteins in quantities of up to several hundred kilograms (e.g., ReoPro, Remicade). However, this method appears to be less common in the industry compared to fed-batch cell culture. Very few companies manufacture their clinical and approved MAb products by using perfusion cell-culture techniques. 

Fed-batch operations can also be operated where soluble nutrients are added to the bed. They can be sprayed onto the bed as a fine mist [89, 90, 129], or simply mixed in with the substrate, such as has been done with soluble starch during a fed-batch culture of Gibberella fujikuroi on wheat bran [130]. This technique of fed-batch operation is appropriate for soluble nutrients which cause substrate inhibition if added in sufficient amounts for the whole fermentation at the start of the fermentation. 

Ahn WS, Park SJ, Lee SY (2001) Production of poly(3-hydroxybutyrate) from whey by cell recycle fed-batch culture of recombinant Escherichia coli. Biotechnol Lett 23 235-240 Alias Z, Tan IKP (2005) Isolation of palm oil-utilising, polyhydroxyalkanoate (PHA)-producing bacteria by an enrichment technique. Bioresource Technology 96(11) 1229-1234 Alvarez HM, Kalscheuer R, Steinbuchel A (1997) Accumulation of storage lipids in species of Rhodococcus and Nocardia and effect of inhibitors and polyethylene glycol. Fett/Lipid 99 239-246... 

The difference between batch and continuous culture techniques with respect to the effect of product inhibition is that under the conditions of continuous cultures product is diluted, while in batch runs product is accumulated. Therefore, in batch cultures reaction rates eventually slow down. In chemostat cultures, however, oscillations of x and p appear due to periodic effect of, for example, pH control and/or permanent inflow and outflow of fresh medium. For the mathematical modeling and computer simulation of this problem, it is possible to formulate the following differential equations ... 

Conventional continuous or batch culture methods suffer from some restrictions that are disadvantageous for technical or economic reasons (e.g., accumulation of toxic and/or inhibition of metabolic end products, limited cell densities, etc.), or are disadvantageous for scientific research purposes (e.g., cultivations are related to the statistical mean of the cell population and not to the individual cell). Recent extensions of the continuous culture methods, that is, dialysis and synchronous culture techniques, are able to fill this gap. 

From the preceding analyses it is apparent that the behavior of reactor systems is more closely linked to the operation of the fermenter chamber than to operation of the reservoir. Therefore, the first step in designing a dialysis culture is to choose between the security and flexibility of batch cultures and the uniformity and economy of continuous techniques. 

The dissection and culture techniques are basically similar when different organs or different developmental stages of tooth germs are studied. Separation of the epithelium and mesenchyme can be accomplished in young tissues, after enzyme treatment, even without dissection, by briefly vortexing the tissues. On the other hand, more advanced tissues require a longer incubation in the enzyme solution (up to lOmin). The time needed for best separation depends also on the batches of enzymes therefore, the optimal time must always be checked for new batches of enzyme and for different tissues. 

Process control a term used in industrial biochemistry, particularly with reference to control of production of microbial fermentation products, e. g. by control of nutrient supply, air supply, etc., and choice of continuous or batch culture. See Fermentation techniques. 

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