Introduction - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 12

The skills of the engineer and of the life scientist are complementary. To convert the prom-
ises of molecular biology into new processes to make new products requires the integration
of these skills. To function at this level, the engineer needs a solid understanding of biology
and its experimental tools. In this topic, we provide sufficient biological background for you
to understand the chapters on applying engineering principles to biosystems. However, if
you are serious about becoming a bioprocess engineer, it is desirable if you had taken courses
in microbiology, biochemistry, and cell biology, as you would appreciate more of the engi-
neering principles in this text.
1.7. THE STORY OF PENICILLIN: THE DAWN OF BIOPROCESS
ENGINEERING
Penicillin is an antibiotic of significant importance. The familiar story of penicillin was well
presented by Kargi and Shuler in their text “Bioprocess Engineering d Basic Concepts.” As
you would expect, the discovery of the chemical was accidental and the production of the
chemical is elaborate. In September 1928, Alexander Fleming at St. Mary's Hospital in Lon-
don was trying to isolate the bacterium, Staphylococcus aureus, which causes boils. The tech-
nique in use was to grow the bacterium on the surface of a nutrient solution. One Friday, the
basement window was accidently left open overnight. The experiments were carried out in
the basement and one of the dishes had been contaminated inadvertently with a foreign
particle. Normally, such a contaminated plate would be tossed out. However, Fleming
noticed that no bacteria grew near the invading substance.
Fleming's genius was to realize that this observation was meaningful and not a “failed”
experiment. Fleming recognized that the cell killing must be due to an antibacterial agent.
He recovered the foreign particle and found that it was a common mold of the Penicillium
genus (later identified as Penicillium notatum). Fleming nurtured the mold to grow and, using
the crude extraction methods then available, managed to obtain a tiny quantity of secreted
material. He then demonstrated that this material had powerful antimicrobial properties
and named the product penicillin. Fleming carefully preserved the culture, but the discovery
lay essentially dormant for over a decade.
World War II provided the impetus to resurrect the discovery. Sulfa drugs have a rather
restricted range of activity, and an antibiotic with minimal side effects and broader applica-
bility was desperately needed. In 1939, Howard Florey and Ernst Chain of Oxford decided to
build on Fleming's observations. Norman Heatley played the key role in producing sufficient
material for Chain and Florey to test the effectiveness of penicillin. Heatley, trained as
a biochemist, performed as a bioprocess engineer. He developed an assay to monitor the
amount of penicillin made so as to determine the kinetics of the fermentation, developed
a culture technique that could be implemented easily, and devised a novel back-extraction
process to recover the very delicate product. After months of immense effort, they produced
enough penicillin to treat some laboratory animals.
Eighteen months after starting on the project, they began to treat a London policeman for
a blood infection. The penicillin worked wonders initially and brought the patient to the
point of recovery. Most unfortunately, the supply of penicillin was exhausted and the man
relapsed and died. Nonetheless, Florey and Chain had demonstrated the great potential