94 • Impacts of Applied Genetics — Micro-Organisms, Plants, and Animals 
the price of sucrose (from sugarcane or sugar 
beets) is not expected to change, the production 
technology is being run at optimum efficiency, 
and the micro-organism is producing as much 
ethanol as it can, the hurdle to economic com- 
petitiveness might be overcome if a less expen- 
sive raw material— cellulose, perhaps— were 
used. But cellulose cannot be used in its natural 
state: physical, chemical, or biological methods 
must be devised to break it down to its glucose 
(also a sugar) components. 
The constraints vary from compound to com- 
pound. But even though the role of genetics 
must be examined on a product-by-product ba- 
sis, certain generalizations can be made. Over- 
all, genetic engineering will probably have an 
impact on three processes: 
• Aerobic fermentation, which produces en- 
zymes, vitamins, pesticides, growth regula- 
tors, amino acids, nucleic acids, and other 
speciality chemicals, is already well-estab- 
lished. Its use should continue to grow. Al- 
ready, complex biochemicals like antibiot- 
ics, growth factors, and enzymes are made 
by fermentation. Amino acids and nucleo- 
tides— somewhat less complicated mole- 
cules— are sometimes produced by fer- 
mentation. Tbeir production is expected to 
increase. 
• Anaerobic fermentation, which produces 
organic acids, methane, and solvents, is the 
industry’s area of greatest current growth. 
Already, 40 percent of the ethanol man- 
ufactured in the United States is produced 
in this way. The main constraint on the 
production of other organic acids and sol- 
vents is the need for cheaper methods for 
converting cellulose to fermentable sugars. 
• Chemical modification of the fermentation 
products of both aerobic and anaerobic 
fermentation, which to date has rarely 
been used on a commercial scale, is of 
great interest. (See table 12.) Cbemical pro- 
duction technologies that employ high tem- 
peratures and pressures might be replaced 
by biological technologies operating at at- 
mospheric pressure and ambient tempera- 
ture. A patent application has already been 
filed for the biological production of one of 
Table 12. — Expansion of Fermentation Into 
the Chemical Industry 
Examples 
Aerobic fermentation 
Enzymes 
. . Amylases, proteases 
Vitamins 
. . Riboflavin Bw 
Pesticides 
. . Bacillus thuringiensis 
Growth regulators 
. . Gibberellin 
Amino acids 
. . Glutamic, lysine 
Nucleic acids 
Acids 
. . Malic acid, citric acid 
Anaerobic fermentation 
Solvents 
. . Ethanol, acetone, n-butanol 
Acids 
. . Acetic, propionic, acrylic 
SOURCE: Office of Technology Assessment. 
these products, ethylene glycol, by the 
Cetus Corp. in Berkeley, Calif. The procc'ss 
is claimed to he more eiK'rgy etlicif'iit and 
less polluting. If it pro\ es succf’sslul w Iumi 
run at an industrial scale, th(* tf'chnology 
could become significant to a U.S. market 
totaling $ 2’/2 billion |)ci’ v(*ar. 
The chemical industry produce's a sarif'ty of 
likely targets for biotechnology. I'ahles l-B-27 
through l-B-32 in ap|)endi.\ l-B present projec- 
tions of the potential economic impacts of ap- 
plied genetics on seUntf'd compounds that 
rejTresent large markets, and the time frame's 
for potential implemientiitiefn. fable' l-B-7 lists 
one large gremp e)f efrganie’ e he'inie’als tluit we're' 
identified by the Ceaiefx Ce)rp. anel Massae hu- 
setts Institute e>f 'fe'e:hne)le)gy (,\iri ) ;is ame'iiable' 
to biotechne)le)gical pre)elue lie)n me'llufels. flu'y 
are in agreement e)ii abe)ul 20 pe'iee'iit e)t the' 
products cited, whie’h unele'rse'eere's the* unee'i- 
tain nature e)f attemipling le) pre'elie t see lar inte) 
the future. 
Fertilizers, polymers, mul pesticides 
Gaseejus amiiUMiia is use'el te) pi efelue e' nitrefge'u 
fertilizers. Ahe)ut 15 hilliefii tefune's eil ammefuia 
were pre)duceHl e he'inieeilly lor this purpe»se‘. in 
1978; the? pre)ce?ss re'e|uire's kirge' amefunts eel 
natural gas. Nitre)ge'U exin eilse) he' e e)in e'l teel. eer 
“fixed,” te) amme)iiia by e'lizyme's in mie re)-e»i>;a- 
nisms; ahe)ut 175 billie)n tefiine's are* lixe-el i)ei 
year, for exani|)le', e)iie' se|u;ire' \.irel e)l lanel 
planted w ith eu'rtain le'gume's (sue h as se>\ bc.msl 
can fix up te) 2 e)unee's e)f nilrefge'ii, UMUg hae 
