Dried-cell system

Before energy balance is calculated, we need to make mass balance. Figure 9.1 shows the material balance for ethanol and glycerol fermentation. Put simply, mass into the system is equal to mass out of die system. The mass of carbon dioxide is calculated by adding mass of dry cell, mass of glycerol, mass of edianol and mass of water at product stream and then subtracting die sum from die feed stream. As a result, die mass of carbon dioxide is defined. The heat of the reaction is calculated by the following equation ... 

Resting cell of G. candidum, as well as dried cell, has been shown to be an effective catalyst for the asymmetric reduction. Both enantiomers of secondary alcohols were prepared by reduction of the corresponding ketones with a single microbe [23]. Reduction of aromatic ketones with G. candidum IFO 5 767 afforded the corresponding (S)-alcohols in an excellent enantioselectivity when amberlite XAD-7, a hydro-phobic polymer, was added to the reaction system, and the reduction with the same microbe afforded (R)-alcohols, also in an excellent enantioselectivity, when the reaction was conducted under aerobic conditions (Figure 8.31). 

Fig. 2. Whole cell biocatalytic reactions for four types of recombinant whole cell systems. Bioconversion reactions were performed in resting cell condition. All data were based on unit cell concentration (1 mg-dry cell weight ml ). Each value and error bar represents the mean of two independent experiments and its standard deviation.

Matsuda recently reported an elegant solution for using a delicate enzyme system in an IL solvent system (Fig. 20). The authors prepared Geotrichum candidum IF05767 dried cell on water-absorbing polymer BL-100 and used... 

What kind of system (open, closed, or isolated) is each of the following cells (a) dry cell (b) fuel cell (c) nicad battery ... 

Metabolic flux this is defined as the amount of the unit of interest, usually the mass of a metabolite in moles (often micromoles, rather) per unit time per unit area or volume, or often grams dry cell weight (dew) [pmol (h g dew)-1] passing between components A and B of the metabolic system. A metabolic rate is equivalent dimensionally to a specific reaction rate. Metabolic flux is the basic unit of observation and modeling in metabolic engineering. 

The use of extracellular lipases of microbial origin to catalyze the stereoselective hydrolysis of esters of 3-acylthio-2-methylpropionic acid in an aqueous system has been demonstrated to produce optically active 3-acylthio-2-methyl-propionic acid [41-43], The synthesis of the chiral side chain of captopril by the lipase-catalyzed enantioselective hydrolysis of the thioester bond of racemic 3-acetylthio-2-methylpropionic acid (15) to yield 5 -(-)-(15) has been demonstrated [44], Among various lipases evaluated, lipase from Rhizopus oryzae ATCC 24563 (heat-dried cells), BMS lipase (extracellular lipase derived from the fermentation of Pseudomonas sp. SC 13856), and lipase PS-30 from Pseudomonas cepacia in an organic solvent system (l,l,2-trichloro-l,2,2-tri-fluoroethane or toluene) catalyzed the hydrolysis of thioester bond of undesired enantiomer of racemic (15) to yield desired S-(-) (15), R-(+)-3-mercapto-2-methylpropionic acid (16) and acetic acid (17) (Fig. 8A). The reaction yield of... 

Fig. 7. Cofermentation of model solutions of glucose and xylose with P. st ip it is and S. cerevisiae separately immobilized (system G) and coimmobilized (system H) in Ca-alginate beads. The gel fraction in system G was made of 0.20 g/g of beads containing P. stipitis and 0.05 g/g of beads containing S. cerevisiae. The initial concentrations of P. stipitis and S. cerevisiae cells were 5.64 x 1012 and 1.89 x 10u cells/L, respectively. The gel fraction in system H was made of 0.25 g/g of beads containing P. stipitis and S. cerevisiae coimmobilized with a loading ratio of P. stipitis/S. cerevisiae of 4 g/g of dry cells. The total cells concentration was 6.01 x 1012 cells/L.

Culture system (mg g-1 dry cell) Condition Maximum Concentration (mg L-1) Volumetric productivity (mg It1 day-1) Net production (mg per fermentor) Specific production Total... 

With heat-dried cells of T. intermedius as PDH source and heat-dried C. boidinii as FDH source, reaction yields of 84% and ee >98% were achieved. As a major drawback of this system the production of T. intermedius could not be scaled up. To solve this problem heat-dried E. coli containing T. intermedius PDH and heat-dried C. boidinii as source of FDH were used. In this procedure, recovery was not a problem and 197 kg allysine ethylene acetal were synthesized in three batches with an average yield of 91% and ee >8%. In a third approach, recombinant Thermo-actinomyces PDH as well as heat-dried methanol-grown Pichia pastoris expressing endogenous FDH were used to produce 15 kg allysine ethylene acetal with a yield of 97% and ee >98%. This process allowed both enzymes to be produced during a... 

Production equipment that cannot be sterilized must be sanitized and disinfected by an appropriate method. This can be done by use of biocides like alcohols (70%), hydrogen peroxide, or formaldehyde-based chemicals or a combination of these. These can either be used for surface disinfections by wiping or spraying or even better by use of gas or dry fog systems for application of the disinfectants. The effect of cleaning and sanitation should be monitored. Microbiological media contact plates can be used to test critical surfaces, as inside the hot cells or glove boxes. The test samples must then be handled and monitored as radioactive contaminated units. 

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