Cultivation technique

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. 

Fig. 7. Scheme for a two-stage continuous cultivation technique. A = acid, 5 = base, M=medium, P = pump, S = substrate, Cl and C2 = base or acid flow, FI = culture flow, F2 = substrate flow, F3 = outflow, Z1 = medium flow... 

Third, as an alternative to the one-stage continuous cultivation technique, especially for the limitation-caused poly(3HB) synthesis discussed above, a two-stage method can be applied. The principle is shown in Fig. 7. 

Opium yields in Myanmar ranged from 8.9 kg/ha in East Shan State to 16.6 kg/ha in South Shan State, where the trend towards improved cultivation techniques seems to continue. The national average is 14.6 kg/ha. Yield increases over the last years have kept production figures stable despite the decreases in cultivation. At 315 mt in 2006, therefore, the level of opium production remained close to 2005 levels. 

The purpose of this chapter is to give art introduction to the basics of microbial, animal, and plant cells and their cultivation techniques and applications. It covers only what is necessary for understanding the terminologies and procedures introduced in this book.1... 

As in the case of enzymes, whole cells can be immobilized for several advantages over traditional cultivation techniques. By immobilizing the cells, process design can be simplified since cells attached to large particles or on surfaces are easily separated from product stream. This ensures continuous fermenter operation without the danger of cell washout. Immobilization can also provide conditions conducive to cell differentiation and cell-to-cell communication, thereby encouraging production of high yields of secondary metabolites. Immobilization can protect cells and thereby decrease problems related to shear forces. 

According to estimates, horseweed may have one of the highest yields of all the plants presented here (see Table 1). Projections indicate that 13.3 t/acre can be taken with current cultivation techniques and no engineering of the plant. Another benefit of horseweed is that it flourishes in dry conditions and in rough soil such as clay and gravel. It is also an early maturing plant and can be harvested as a fuel as early as September. 

Before considering the cultivation techniques it is important to distinguish between in vitro culture conditions which provide mere survival and those which allow growth, development and maturation to occur. The term survival is here interpreted as implying merely the maintenance of an organism in vitro at a metabolic level sufficient to keep its cells and tissues alive, but not sufficient to allow growth and differentiation to occur at the appropriate rate and in a normal manner. 

One of the limitations of screening environmental isolates is the cultivation of the organisms. In a single gram of soil, more than 108 microbes may be present, the majority of which cannot be cultivated. It is clear from molecular ecological studies that traditional cultivation techniques only capture a fraction, usually less than 1 percent, of the available diversity. To overcome this, direct cloning of DNA from environmental samples enables an unbiased representation of the microbial... 

Many naturally occurring plant extracts are reputed to possess anti-irritant properties and have been recommended for use in cosmetic formulations. These include such diverse mixtures as tea tree oil, borage seed oil, Paraguay tea extract. Kola nut extract, oil of rosemary, and lavender oil. It is, however, difficult to standardize plant extracts and there may be a great deal of lot-to-lot variability in constituents. Understandably, this makes identification and isolation of any specific active constituent complex and laborious. The extracts may be oily or hydrophilic and contain compounds such as a-bisabolol, xanthines, polyphenols, and phytosterols.There is great potential in the use of plant extracts for irritation and sensitization reduction. This has been established within the cosmetic industry, and interest here has stimulated activity into reducing variability by more consistent cultivation techniques and more standardized extraction methods. 

Modern agricultural research commonly proceeds as if yields, per unit of scarce inputs, were the central concern of the farmer. The assumption is enormously convenient like the commercial wood of scientific forestry, the generic, homologous, uniform commodities thus derived create the possibility both of quantitative comparisons between the yield of different cultivation techniques and of aggregate statistics. The familiar tabulations of acres planted, yields per acre, and total production from year to year are usually the decisive measure of success in a development program. 

Propagation and Cultivation Techniques for Heracleum candicans Wall A Himalayan Medicinal Resource in Peril... 

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