Semi-continuous culture

Johansson N, Graneli E (1999) Influence of different nutrient conditions on cell density, chemical composition and toxicity of Prymnesium parvum (haptophyta) in semi-continuous cultures. J Exp Mar Biol Ecol 239 243-258... 

Harrison, P. J., Turpin, D. H., Bienfang, P. K., and Davis, C. O. (1986). Sinking as a factor affecting phytoplankton species succession The use of selective loss semi-continuous cultures. J. Exp. Mar. Biol. Ecol. 99, 19-30. 

Periodic medium replacement (semi-continuous culture)... 

Cartridge and membrane filter systems tested in preliminary studies in our laboratories have proved to be applicable to eukaryotic cell culture processes, i.e. cell removal, semi-continuous culture growth, cell culture concentration and recycling. Present membrane systems are limited in processing volume cartridges are scalable, but have a narrower range of application. 

BROWN M R, GARLAND C D, JEFFREY S W, JAMESON I D and LEROI J M (1993b) The grOSS and amino acid compositions of batch and semi-continuous cultures of Isochrysis sp. (clone T.ISO), Pavlova lutheri and Nannochloropsis oculata. Journal of Applied Phycology, 5,285-296. 

Taheri R, Nouhi A, Hamedi J, Javaherdashti R (2005) Comparison of corrosion rates of some steels in batch and semi-continuous cultures of sulfate-reducing bacteria. Asian J Microbiol Biotech Env Sc 7(l) 5-8... 

Due to practical limits such as difficulty in establishing and running continuous and/or semi-continuous cultures, some MIC experimenters do the tests in batch-type cultures. In these cultures, a certain amount of food (nutrients) is pro-... 

Carro, M.D. and E.L. Miller, 1999. Effect of supplementing a fibre basal diet with different nitrogen forms on ruminal fermentation and microbial growth in an in vitro semi-continuous culture system (Rusitec). Br. J. Nutr. 82,149-157. Martin, C., A.G. Williams and B. Michalet-Doreau, 1994. Isolation and characteristics of the protozoal and bacterial fractions from bovine ruminal contents. J. Anim. Sci. 72, 2962-2968. 

Manning, B. W., T. W. Federle, and C. E. Cemiglia. 1987. Use of a semi-continuous culture system as a model for determining the role of human intestinal microflora in the metabolism of xenobiotics. J. Microbiol. Methods 6 81-94. 

Alkaloids can be produced in batch suspension cultures, semi-continuous and continuous cultures. Batch suspension cultures multiply the cells in a liquid medium by using a closed system in which only gases are changed. Generally,... 

The bioreactor operation mode is normally defined at the outset of process configuration. Insect cells have been cultured in almost all known cultivation modes batch [10], repeated-batch [70], perfusion [71-74], fed-batch [75, 76], semi-continuous [77,78] and continuous [79]. In spite of this multitude of different strategies, the batch or, eventually, fed-batch mode is normally preferred due to the lytic infection cycle of the baculovirus. 

Information on animal cell metabolism is essential for the formulation of new culture media, as well as for the composition of the most appropriate nutrient feed that may be used in various strategies of batch, semi-batch or continuous culture that may be designed for the production of the targeted protein. As already discussed in detail in Chapter 4 and concisely presented in Figure 5.1, two fundamental substrates for animal cells are glucose and glutamine. 

Scheme 2. Affinity chromatography bioreactor (ACBR) for the semi-continuous recovery of plant-produced proteins. Media is drawn up through the intake nozzle (D) during culture, through a pre-filter (B) that removes particulates, and then to a protein-collection column (C) using a peristaltic pump. After protein binding, the media is returned to the growth chamber. Humidified air is supplied to the culture through a sterile pre-filter (A) [62]...

Semi-continuous batch culture this is in effect a batch culture that is partially harvested (e.g. 70%), topped up with fresh medium, allowed to grow up and then harvested again. Typically, three or four harvests can be made, although usually with diminishing returns at each harvest... 

Kim, J. S., Ito, K., Izaki, K. and Takahashi, H. (1987a). Production of molecular hydrogen by a semi-continuous outdoor culture of Rhodopseudomonas sphaeroides. Agric. Biol. Chem. 51, 1173-1174. 

The same cartridge filters with 2-4 sq. ft. surface area were employed in a pilot-scale production facility for semi-continuous growth of a murine lymphokine-producing cell line. This was done as dead-end filtrations, harvesting 80 to 85% of the 20-40 liter culture as cell-free filtrate and retaining 15 to 20% for inoculum to be regrown after volume restoration with fresh medium. No attempts were made to recirculate or back-flush the filter cartridges. 

Enzyme and Its Assay. Culture filtrates from 10 liter batch or semi-continuous submerged fermentations of Trichoderma viride QM 6a were... 

Kutney et al. have studied the production of podophyllotoxin derivatives using cultures of Podophyllum peltatum and Catharanthus roseus [126-128X In particular they have established procedures for the biotransformation of readily prepared dibenzylbutyrolactones into podophyllotoxin derivatives using a semi-continuous fermentation process (scheme 58). However, even here the major products obtained belong to the 1,2-trans- (isopodophyllotoxin) series. 

The fourth step in the direct ethanol process is considered to be key to the economic viability of the bioconversion of cellulose to chemicals. The pretreated cellulose slurry is simultaneously converted to glucose and the glucose to ethyl alcohol in the same vessel in a continuous or semi-continuous mode. The enzyme sample is the whole culture from the enzyme production vessel. The feedstock is a slurry of 7.5% to 15% cellulose. The yeast is either added as a cake or recycled as a cream. 

Degradation of organopollutants by fungal cultures has been carried out successfully at bench and pilot scale, preferentially in batch or semi-continuous operations (Alleman et al. 1995 Fujita et al. 2002 Mielgo et al. 2002). Continuous treatment systems are desirable alternatives to increase process efficiency. A modified conventional configuration (fixed-bed bioreactor) coupled with a pulsation system has... 

Alkaloids can be produced in batch suspension cultures, semi-continuous and continuous cultures. Batch suspension cultures multiply the cells in a liquid medium using a closed system in which only gases are changed. Generally, this method contains the following phases (1) inoculation of cells into the medium, (2) a lag phase in which cells grow slowly, (3) a rapid division phase, and (4) slower division. The duration of Phase 2 is from 0 to 9 days and of Phase 3 is 9 days and replaced by a new medium. In this way, cell growth is continuous, despite cells from different mediums. In continuous cultures, a fresh medium is continuously added. Two open systems are... 

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