Ch. 5 — The Chemical Industry • 87 
alone ser\ es as the basic chemical tor the manu- 
facture of half of the largest \olume industi'ial 
chemicals. Kach of the steps in a chemical con- 
\ ersion process is controlled hv a separate reac- 
tion, u hich is often performed hv a separate 
compan\-. 
pAaluating the competiti\eness both of a 
process and of the market is critical for the 
chemical industry, which is intensixe for cap- 
ital, energy, and raw materials. Its plants use 
large amounts of energx’ atid can cost hundreds 
of millions of dollars to build, and raw material 
costs are generally 5t) to 80 percent of a prod- 
uct’s cost. If a biological process can use the 
same raw materials and reduce the process cost 
by even 20 percent, or allow the use of inexpen- 
sive raw materials, it could prox ide the industry 
xvith a major price break. 
Fermentation and 
the chemical industry 
The production of industrial chemicals by 
fermentation is not nexv. Scores of chemicals 
hax e been produced by micro-organisms in the 
past, only to be replaced by chemical produc- 
tion based on petroleum. In 1946, for example, 
27 percent of the ethyl alcohol in the United 
States xvas produced from grain and grain prod- 
ucts, 27 percent from molasses, a fexv percent 
each from such materials such as potatoes, pine- 
apple juice, cellulose pulp, and xvhey, and only 
36 percent from petroleum. Ten years later 
almost 60 percent xvas derived from petroleum. 
Exen more dramatically, fumaric acid xvas at 
one time produced on a commercial scale 
through fermentation, but its biological produc- 
tion xvas stopped xvhen a more economical syn- 
thesis from benzene xvas dex eloped. Frequently, 
after a fermentation product xvas discovered, 
alternative chemical synthetic methods xvere 
soon dexeloped that used inexpensive petro- 
leum as the raxv niaterial. 
Nevertheless, for the fexv chemical entities 
still produced by fermentation, applied genetics 
has contributed to the economic viability of the 
process. The production of citric and lactic 
acids and xarious amino acids are among the 
processes that haxe benefited from genetics. 
Lactic acid is produced both synthetically and 
by fei'inentation. t)x er the past 10 to 20 years, 
manufacture by fermentation has experienced 
competition from chemical processes. 
The organisms used for the production of lac- 
tic acid are x arious species of the bacterium Lac- 
tobacillus. Starting materials may be glucose, su- 
crose, or lactose (xvhey). The fermentation per 
se is efficient, I'esulting in 90 percent yields, de- 
pending on the original carbohydrate. Since 
most of the problems in the manufacture of lac- 
tic acid lie in the recox ery procedure and not in 
fermentation, fexx’ attempts have been made to 
improxe the industrial processes through 
genetics. 
Citric acid is the most important acidulant, 
and historically has held oxer 55 to 65 percent 
of the acidulant market for foods.* It is also 
used in pharmaceuticals and miscellaneous in- 
dustrial applications. It is produced commercial- 
ly by the mold Aspergillus niger. Surprisingly lit- 
tle xvork has been published on improving citric 
acid-producing strains of this micro-organism. 
W eight yields of 110 percent have recently been 
reported in A. niger mutants obtained by ir- 
radiating a strain for which a maximum yield of 
29 percent had been reported. 
Amino acids are the building blocks of pro- 
teins. Txxenty of them are incorporated into 
proteins manufactured in cells, others serve 
specialized structural roles, are important meta- 
bolic intermediates, or are hormones and neu- 
rotransmitters. All of the amino acids are used 
in research and in nutritional preparations, 
xvith most being used in the preparation of 
pharmaceuticals. Three are used in large quan- 
tities for txvo purposes: glutamic acid to manu- 
facture monosodium glutamate, which is a fla- 
*The other two important acidulants, or acidifying agents, are 
phosphoric acid (20 to 25 percent) and malic acid (5 percent). 
