Ch. 3— Genetic Engineering and the Fermentation Technologies • 55 
(lenetic engineei'ing can increase an orga- 
nism's proclnetixe eapal)ility (a change that can 
make a process economically competitix e); hot it 
can also be used to construct sti'ains w ith char- 
acteristics other than higher [)roclucli\ ity. Prop- 
erties such as objectionable coloi', odor, or slime 
can he I'emoved. Ihe formation of spores that 
could lead to airborne spread of the micro- 
organism can he su[)pressed. The formation of 
harmful hv})roducts can he eliminated oi' re- 
duced. Other pi’opei'ties, such as I’esistance to 
bacterial \ iruses and increased genetic stability, 
can he gix en to micro-organisms that lack them. 
.-\p[)lying recent genetic engineering tech- 
niques to the production of industrially \ aluahle 
enzymes may also prove useful in the tuture. 
For e.xample, a strain of micro-organism that 
carries the genes for a desired enzyme may he 
pathogenic. If the genes that e.xpress ([jroduce) 
the enzyme can he transferred to an innocuous 
micro-organism, the enzyme can he produced 
safely. 
Cl RREiN'T TECH.MC.XL LIVRTS (),\ 
GENETIC ENGINEERING 
Despite the many genetic manipulations that 
are theoretically possible, there are several 
notable technical limitations; 
• Genetic maps— the identification of the lo- 
cation of desired genes on various chromo- 
somes have not been constructed for most 
industrially useful micro-organisms. 
• Genetic systems for industrially useful 
micro-organisms, such as the availability of 
useful vectors, are at an early stage of 
development. 
• Physiological pathways— the sequence of 
enzymatic steps leading from a raw mate- 
rial to the desired product, are not known 
for many chemicals. Much basic research 
will be necessary to identify all the steps. 
The number of genes necessary for the con- 
version is a major limitation. Currently, 
rDNA is most useful when only a single 
easily identifiable gene is needed. It is more 
difficult to use when several genes must be 
transferred. Finally, the problems are for- 
midable, if not impossible, when the genes 
have not yet been identified. This is the 
case with many traits of agronomic impor- 
tance, such as plant height. 
Fven if the genes are identified and suc- 
cessfully transferred, methods must he de- 
veloped to recognize the bacteria that re- 
ceived them. Fhei'efore, the need to devel- 
op appropi'iate selection methods has im- 
peded the application of molecular ge- 
netics. 
,\s a conse(|uence of these limitations, genetic 
engineei'ing will he applied to the development 
of capabilities that re(|uii’e the transfer of only 
one or a few identified genes. 
Fermentation and industry 
Genetic engineei'ing is not in itself an indus- 
try, but a technology used at the laboratory 
level. It allows the researcher to alter the hered- 
itary apparatus of a living cell so that the cell 
can produce more or diffei’ent chemicals, or 
perform completely new functions. Fhe altered 
cell, or more appropriately the population of 
altered identical cells is, in turn, used in indus- 
trial production. It is within this framework that 
the impacts of applied genetics in the various in- 
dustries is examined. 
Regardless of the industry, the same three 
criteria must be met before genetic technologies 
can become commercially feasible. These cri- 
teria represent major constraints that industry 
must overcome before genetic engineering can 
play a part in bringing a product to market. 
They include the need for: 
1. a useful biochemical product; 
2. a useful biological fermentation approach 
to commercial production; and 
3. a useful genetic approach to increase the 
efficiency of production. 
The three criteria interrelate and can be met 
in any order; the demonstration of usefulness 
can begin with any of the three. Insulin, e.g., 
was first found to have value in therapy; 
fermentation was then shown to be useful in 
its production; and, now genetic engineering 
promises to make the fermentation process eco- 
nomically competitive. In contrast, the value of 
thvmosin a-l, has not vet been proved, although 
