In stressing the importance of antibiotics as harmful microbes killers, we may have narrowed our focus too sharply, creating the impression that the only import of bacteria to man lies in their relation to disease. However, a useful role looms large, "bacteria as manufacturers". Microbiologists, chemists, and engineers have pooled their talents to develop industrial processes in which microorganisms, and their enzymes, produce a variety of useful compounds. These techniques center about their fermentation process, whereby chemical changes are produced in an organic substance through the action of microbial enzymes.
All of us know about the role of yeasts in the production of beer, ale, and other malt beverages, wines and the fermented mashes from which whiskey and other distilled spirits are produced. However, we overlook the comparable role of bacteria in producing lactic acid, vinegar, dextrans, sorbose (employed in the synthesis of ascorbic acid), the flavor enhancer, monosodium glutamate, the amino acid lysine, used to supplement the food value of cereal grains, and vitamin B12. Some bacteria like Bacillus thuringiensis produce bioinsecticides which kill insect larvae which consume them. They can be used to control insects that destroy alfalfa, cabbage, and tomato.
The fermentation industry is an important resource. Looking toward the future, one of its major roles may be to exploit the synthetic prowess of microorganisms not only to manufacture complex substances but to destroy waste products of our complex civilization.