10
Chapter
2
Table 2.1 List of some fermentation products and some market values in year 2000
Category of Product
Product
Tvpical organism
M arket value
Whole cells
Baker’s yeast
Saccharomyces cerevisiae
Lactic acid bacteria
Lactic acid bacteria
Single cell protein
Methylotrophic bacteria
Primary metabolites
Beer, wine
Saccharomyces cerevisiae
Saccharomyces
Ethanol
carls berge ns is
Saccharomyces cerevisiae
12 billion US$
Lactic acid
Zymomonas mobilis
Lactic acid bacteria
200
million US$
Citric acid
Rhizopus oryzae
1.5 billion US$
Glutamate
Aspergillus niger
1 billion US$
Lysine
Corynebacterium glutamicum
500 million US$
Phenylalanine
Corynebacterium glutamicum
Escherichia coli
200
million US$
Secondary metabolites
Penicillins
Penicillium chrysogenum
4 billion US$
Cephalosporins
Acremonium chrysogenum
Streptomyces clavuligerus
11 billion US$
Statins
Aspergillus terreus
9 billion US$
Taxol
Plant cells
1
billion US$
Recombinant proteins
Insulin
Saccharomyces cerevisiae
Escherichia coli
3 billion US$
tPA
Chinese Hamster Ovary cells
1
billion US$
Erythropoietin
Chinese Hamster Ovary cells
3.6 billion US$
Human growth hormone
Escherichia coli
I billion US$
Interferons
Escherichia coli
2 billion US$
Vaccines
Bacteria and yeast
Monoclonal antibodies
Hybridoma cells
700 million US$
Enzymes
Detergent enzymes
Bacilli, Aspergilli
600 million US$
Starch industry
Bacilli, Aspergilli
200 million US$
Chymosin
Aspergilli
Polymers
Xanthan gum
Xanthomonas campestris
400 million US$
Polyhydroxyalkanoates
Alcaligenes erytrophus
DNA
Vaccines
Escherichia coli
Gene theraov
Escherichia coli
2.1 Cellular Growth
Cellular growth is the net result of the uptake and conversion of nutrients - often called
substrates, into new cell material - often called biomass. Fig. 2.1 is a schematic view of cellular
growth and some of the associated reactions. Cellular growth is an autocatalytic process, as one
cell is responsible for the synthesis of more cells, and at conditions with excess nutrients growth
is therefore exponential with a certain doubling time for the number of cells. Besides the
formation of new biomass (or new cells), the break down (or catabolism) of substrates leads to
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