Immobilized cultures

Fungal cultures are used as free or immobilized cultures for decolorization processes under static and/or agitated conditions. Free cell cultures could decolorized... 

Cell immobilized cultures of Phanerochaete chrysosporium and repeated-batch decolorization were reported by Yang and Yu [46]. Diazo-dye Red 533 was decolorized by PuF immobilized culture, and decolorization efficiency of 80% or higher was achieved within a period of 1 or 2 days. 

The dye Poly R-478 was decolorized to a much greater extent and at slightly faster rate when the culture was supplemented with Mn(II), while the opposite was obtained for Poly S-119. They found a correlation between polymeric dye decolor-ization and peroxidative activity of fungus under static or immobilized condition in air-lift bioreactor. Immobilized culture produced LiP and MnP enzymes over a longer time than static cultures. 

The immobilization of the white rot fungus F. trogii in Na-ALG beads allowed the decolorization of the dye Acid Black 52 in a stirred tank reactor operated in batch [55]. Three enzymes, laccase, MnP, LiP, secreted by fungus were reported during decolorization process. Results showed that laccase enzyme activity increased with increasing alginate concentration from 0 to 4%. Cell growth at immobilized cultivation was maintained more stably than suspended cultivation. Total amount of removed dye was reported to be 469 mg/L for immobilized cultures and 440 mg/L for suspended cultures. 

Decolorization of azo dye R016 by immobilized cultures of I. lacteus was compared in three different reactor systems [59]. Different size of PuF was used for immobilization in reactors. Biomass concentration was reported to be 11.6, 8.3, and 4.9 g dw/L in Small Trickle Bed Reactor (STBR), Large Trickle Bed Reactor, and Rotating Disk Bioreactor, respectively. Decolorization rate was found high in STBR, where 90% decolorization rates were achieved after 3 days. Dye decolorization was highly efficient, but no direct relationship between the extracellular enzyme activities (laccase and MnP) and dye decolorization capacity was found. 

Buckley KF, Dobson ADW (1998) Extracellular ligninolytic enzyme production and polymeric dye decolourization in immobilized cultures of Chrysosporium lignorum CL1. Biotechnol Lett 20 301-306... 

HYDROGEN PRODUCTION BY SUSPENSION AND IMMOBILIZED CULTURES OF PHOTOTROPHIC MICROORGANISMS. TECHNOLOGICAL ASPECTS. 

Hydrogen Production by Suspension and Immobilized Cultures of Phototrophic Microorganisms 59... 

Table 3. Maximum hydrogen production rates by immobilized cultures of purple bacteria...

Three different approaches for the cultivation of isolated hematopoietic cells have been described, the static, the stirred and the immobilized culture. Static cultivation takes place in very simple culture systems like well plates, tissue-culture flasks or gas-permeable culture bags [62, 63]. As the first two systems do not allow cell cultivation on a clinical scale, the latter is actually the most often used technique for stem cell expansion. All these systems have the advantage of being easy to handle, single-use devices, which enable an uncomplicated cell harvest. But all of them do not offer possibilities for process control or continuous feeding. This causes variations in culture conditions during fermentation (e.g., oxygen tension, pH, substrate, metabolite and cytokine concentrations). 

Table 1. Total number of embryos and plantlets in the suspension culture and in the immobilized culture...

Immobilized culture supplemented with CaCl2 Suspension culture... 

Embryogenic rice calli tend to form larger clumps during cultivation. Therefore, immobilization of the calli has hardly been carried out until now. Porous supports such as polyurethane foam have often been used for the immobilization of mycelial cells [64, 65] and plant cells [66-68]. In almost all cases, effective production of biological materials by the immobilized cells has been reported. To avoid the damage due to the hydrodynamic stress, we proposed the immobilization culture of rice callus using a macroporous urethane foam support. A turbine-blade reactor (TBR), which has been developed for hairy root culture, was also used in the culture. In the culture space, polyurethane foam was added as an immobilization support. 

In order to address the low cell density issue associated with sulfur-deprived cell suspensions, cell immobilization strategies have been investigated. This resulted in an 18 times increase in the H2-production rates on a per-cell culture volume basis and a 6 times longer period of H2 production by algal cultures immobilized on glass fibers.138 Additionally, the immobilized cultures have increased productivity (2.5 times) on a per illuminated area basis, compared to cell suspensions. 

A number of different types of plant tissue cultures (e.g. suspension cultures, differentiated cultures, immobilized cultures, and transformed cultures) have been studied for the production of flavouring substances [14-19]. As de novo biosynthesis has been found unsuccessful in most cases (exceptions are shown in Tab. 3.5.), biotransformation of added precursors has been studied extensively. Fig. 3.4 shows some examples of biotransformation of terpenes by suspension cultures. Tab. 3.6 lists some biotransformations by suspension or immobilized cultures. 

Table 3.6 Bio transformation of various substrates by suspension or immobilized cultures [16, 23-26]...

Factors affecting H2 photoproduction by purple bacteria are described in this minireview. Based on comparison of maximum H2 photoproduction rates by suspension and immobilized cultures, it is concluded that immobilized culture is more attractive for application. Possibility for scaling up of photobioreactors with immobilized purple bacteria is discussed. 

However, for the creation of a practical, scalable photobioreactor with immobilized culture(s) efforts must consider these questions ... 

Immobilized Culture. Immobilization of plant cells was first reported by Brodelius et al. in 1979,1 1 and since then many reports have been published. Unfortunately, an immobilized cell culture technique has not yet been established as an industrial process for secondary metabolite production. However, this technique has many excellent features and should be the subject of future development research. 

Mitsui Petrochem Ind KK. J6 0227-691-A. 26-04-84-JP-082953(12-10-85). Manufacturing of berberine by immobilized cultured cells of Thalictrum minus L. var. hypoleucum Miq. (r. thunbergii DC.). 

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