88 • Impacts of Applied Genetics — Micro-Organisms, Plants, and Animals 
vor enhancer particularly in oriental cooking;* 
and lysine and methionine as animal feed ad- 
ditives. 
Conventional technology for producing glu- 
tamic acid is based on pioneering work that was 
subsequently applied to other amino acids. The 
production employed microbial strains to pro- 
duce amino acids that are not within their nor- 
mal biosynthetic capabilities. This was accom- 
*Monosodium glutamate is the sodium salt of glutamic acid. In 1978, 
about 18,000 tonnes were manufactured in the United States and about 
11,000 tonnes imported. The food industy consumed 97 percent. The 
fermentation plant of the Stauffer Chemical Co. in San Jose, Calif., is 
the sole U.S. producer. The microbes used in glutamic acid fermenta- 
tion [Corynebacterium glutamicum, C. lileum, and Brevibacterium 
flavum) produce it in 60 percent of theoretical yield. Thus, there is some 
but not great potential for the use of applied genetics to improve the 
yield. Many of the genetic approaches have already been thoroughly 
investigated by industrial scientists. 
plished by using two methods: 1) manipulating 
microbial growth conditions, and 2) isolating 
naturally occurring mutants. 
Although microbial production of all the 
amino acids has been studied, glutamic acid and 
L-lysine** are the ones produced in significant 
quantities by fermentation processes. (See table 
9.) The production of L-lysine is an e.xcellent e.\- 
**The lack of a single amino acid can retard protein synthesis, and 
therefore growth, in a mammal. The limiting amino acid is a function of 
the animal and its feed. The major source of animal feed in the United 
States is soybean meal. The limiting amino acid for feeding swine is 
methionine; the limiting amino acid for feeding poultry is lysine. 
Because of increased poultry demand, world demand for lysine is 
climbing. Eurolysine is spending $27 million to double its production 
capacity in Amiens, France, to 10 thousand tonnes. The Asian and 
Mideast markets are estimated to increase to 3 thousand tonnes in 
1985. Some bacteria produce lysine at over 90 percent of theoretical 
yield. Little genetic improvement is likely in this conversion yield, 
however, significant improvement can be made in the rate and final 
concentration. 
Table 9.— Data for Commercially Produced Amino Acids^ 
Price March 
Potential for application of 
1980 (per kg 
Production 1978 
biotechnology (de novo synthesis or 
Amino acid 
pure L) 
Present source 
(tonnes) 
bioconversion; organisms and enzymes) 
Alanine 
$ 80 
Hydrolysis of protein; 
10-50(J)b 
— 
chemical synthesis 
Arginine 
28 
Gelatin hydrolysis 
200 - 300 (J) 
Fermentation in Japan 
Asparagine 
50 
Extraction 
10-50 (J) 
— 
Aspartic acid 
12 
Bioconversion of 
fumaric acid 
500-1,000 (J) 
Bioconversion 
Citrulline 
250 
— 
10-90(J) 
Fermentation in Japan 
Cysteine 
50 
Extraction 
100-200 (J) 
— 
Cystine 
60 
Extraction 
100-200 (J) 
— 
DOPA (dihydrophenylalanine) . 750 
Chemical 
100-200 (J) 
— 
Glutamic 
4 
Fermentation 
10,000-100,000 (J) 
De novo: Micrococcus glutamicus 
Glutamine 
55 
Extraction 
200 - 300 (J) 
Fermentation in Japan 
Histidine 
160 
— 
100-200 
Fermentation in Japan 
Hydroxyproline 
280 
Extraction from collagen 10 - 50 
— 
Isoleucine 
350 
Extraction 
10-50 (J) 
— 
Leucine 
55 
— 
50-100 (J) 
Fermentation in Japan 
Lysine 
350 
Fermentation (80%) 
10,000 (J) 
(80% by fermentation) De novo: 
Chemical (20%) 
Corynebacterium glutamicum and 
Brevibacterium tlavum 
Methionine 
265 
Chemical from acrolein 
17.000 (D,L)c 
20.000 (D,L) (J) 
— 
Ornithine 
60 
— 
10-50 (J) 
Fermentation in Japan 
Phenylalanine 
55 
Chemical from 
50-100 (J) 
Fermentation in Japan 
benzaldehyde 
Proline 
125 
Hydrolysis of gelatin 
10-50 (J) 
Fermentation in Japan 
Serine 
320 
— 
10-50 (J) 
Bioconversion in Japan 
Threonine 
150 
— 
50-10(J) 
Fermentation in Japan 
Tryptophan 
110 
Chemical from indole 
55 (J) 
— 
Tyrosine 
13 
Extraction 
50-100 (J) 
-- 
Valine 
60 
— 
50-100 (J) 
Fermentation in Japan 
^Production data largely from Japan because of relative small U.S. production. 
*^Japan. 
'-D and L forms. 
SOURCE: Massachusetts Institute of Technology. 
