MECHANICAL engineers represent one of the oldest engineering specialties. Biotechnology companies are one of the newest growth industries. And the new has a desperate need for the old.
''We could use 5, 000 mechanical engineers in biotech companies, and there are almost none, '' Dr. Robert C. Dean Jr. said last week. He is chairman of the Verax Corporation of Lebanon, N.H., a maker of equipment for biotech companies, and an adjunct professor at Dartmouth College's engineering school.
Dr. Dean also heads a special committee set up recently by the American Society of Mechanical Engineers to do something about what he called ''a crisis.''
The idea is to persuade more mechanical engineers to take courses that will enable them to handle vital jobs in the biotech industry. ''There is a great future for them.'' Dr. Dean said.
Courses needed - and not usually taken by mechanical engineers in their undergraduate years - include cellular and molecular biology, organic chemistry and process engineering, which includes computer simulation.
Dr. Kris Venkat, corporate director of science and technology at the H. J. Heinz Company and visiting professor of chemical engineering at Rutgers University, said he agreed with Dr. Dean.
''I would add a course in instrumentation, '' Dr. Venkat said. ''All engineers need more breadth today. Historically engineering has been very discipline oriented. I tell my own students in chemical engineering that we don't know what training they will need in five years or so.''
''We certainly need more sophistication'' in production, he added.
Dr. Dean said: ''For every three engineers in biotech companies, we need two with a biochemical background and one with a mechanical engineering background.
''Over 200 medical protein products are in the Food and Drug Administration pipeline awaiting approval.''
The new medical protein products will seek to eradicate AIDS, hepatitis, cancer and malaria and other parasitic diseases. Later will come agricultural proteins to help crops, which, Dr. Dean said, ''will have eventually as large an impact on mankind as medical proteins.''
As products move out of the laboratory into production, there are many problems to be solved. A serious one involves asepsis, or keeping products purified and free from infectious materials.
For example, new and more efficient seals for equipment are important because at a point where two production pipelines are sealed together, infectious material can accumulate. Filtration, heat transfer, flow measurements and instrument controls, as well as the ability to handle equipment breakdowns - all are the province of mechanical engineers.
''Cost reduction is another major challenge, '' Dr. Venkat said. Production techniques must be devised to lower costs so that biotech products can be sold cheaply enough to reach a vast public.
The need for mechanical engineers reflects a larger world problem -and opportunity - for American biotech companies. Much pioneering work has been done in this country, and scientists worry that if engineers cannot solve commercialization problems, the industry cannot remain competitive with Japanese and European companies. Impetus will be lost along with profits.