270 • Impacts of Applied Genetics — Micro-Organisms, Plants, and Animals 
cleaner. Only APAP would accumulate: all other 
metabolites are naturally occurring. Even micro- 
organisms could be collected after each batch and 
processed into a cake for use as a high protein 
animal feed. 
Biological parameters 
MICROBIAL PATHWAY 
A proposed pathway for converting aniline to 
APAP via the acetylation of an intermediate, p-amino- 
phenol, is shown in figure l-A-1. Various tungi have 
been identified in which these reactions occur. ^ 
^R. V. Smith and J. P. Rosazza, "Microbial Models of Mammalian 
Metabolism," J. Pharmaceut. Sci. 64:1737-1759, 1975. 
“R. Smith and J. P. Rosazza, "Microbial Models of Mammalian 
Metabolism: Aromatic Hvdro.wlation," Arch. Biochem. Biophys. 
161:551-558, 1974. 
^V'. R. Munzner, E. Mutschler, and M. Riimmel, "Uberdie mikro- 
biologiscbe unwandlung N-baltiger substrate" (Concerning the 
Microbiological Transformation of N- containing Substrate), Plant 
Medica 15:97-103, 1967. 
Figure l-A-1. Bioconversion of Aniline to APAP^ 
NHCOCH 3 
Aniline 
SaPAP = N-acetyl-p-aminophenol = acetaminophen = p-acetamidophenol = 
p-hydroxyacetanilide = Tylenol (trade name of McNeil Laboratories). 
SOURCE; Genex Corp. 
/Mternatively, aniline could he acetylated directly 
forming acetanilide, which in turn would he hydro.x- 
vlated to APAP.'“ A number of Streptomyces spe- 
cies have been found to coiwert acetanilide to 
APAP. The pathway imoh ing p-aminophenol was 
chosen simply because the conversion efficiency of 
acetic acid to APAP would he slightly higher if acetic 
acid entered the overall reaction at the second step 
rather than at the first step. 
HOST MICRO-ORGANISMS 
The most suitable micro-organism for jiroduction 
of APAP in large-scale fermentation may not neces- 
sarilv be one that normally metabolizes aniline or 
/i-aminophenol. While a h^ictei'ium might ser\e as a 
suitable host for insertion and e.xpression ol the req- 
uisite genes, a yeast may represent a better choice. It 
will prohablv more closely resemble the organism 
from which the genes are isolated. 
Fermentation efficiencies 
CONVERSION EFFICIENCIES 
The molar and weight comersion efficii’iicic's for 
the bioconversion of feedstock to product are pro- 
jected in table I-A-1. I'be biocom crsion of aniline to 
'“Smith, et al., op. oil. 
"Munzner, el al., op. cil. 
'^R. J. Thei'iaull and I . It. I.ongfield. 'Microbial ( omeiMon ot 
.Acetanilide to 2 ’-Hvdro.wacetanilide and 4’ Uydro.wacetanilide." 
Apt. Microbiol. 15:1431-1436. 1967. 
‘"Ibid. 
Table l-A-1. — Fermentation Efficiencies to Meet the 
Requirements for the Production of Acetaminophen 
(APAP) From Aniline 
Overall molar conversion efficiency of: 
(a) Aniline to APAP 90.25% 
(b) Acetic Acid to APAP 95.0 
Overaii weight conversion efficiency of: 
(a) Aniline to APAPa 146.5 
(b) Acetic Acid to APAP® 239. 1 
Utiiization of: 
(a) Aniline in fermentation broth 2.28lb/gal 
(b) Acetic acid in fermentation broth ... 1 . 39/gal 
Production of APAP in broth 3.34 Ib/gal 
Batch voiume 33,500 gal 
Recovery efficiency 90.0 % 
Yield of APAP/batch 100,701 lb 
Number of batches/year 100 
Annual yield of product 10,070,100 lb 
Overall weight conversion of precursor to APAP ■ 
molecular weight of APAP y molarconvf rston effti ? 
molecular weight of precursor of precursor to APAP 
SOURCE: Genex Corp. 
