Chemical manufacture of organic molecules such as alcohols and acetone rely on starting materials made from petroleum. Additionally, the use of petroleum has concomitant environmental and political problems. Interest in microbial fermentations is experiencing a renaissance. Plant starch, cellulose from agricultural waste, and whey from cheese manufacture are abundant and renewable sources of fermentable carbohydrates. Additionally these materials, not utilized, represent solid waste that must be buried in dumps or treated with waste water.
Microbial fermentations have other benefits.
For one, they don't use toxic reagents or require the addition of intermediate reagents. Microbiologists are now looking for naturally occurring microbes that produce desired chemicals. In addition, they are now capable of engineering microbes to enhance production of these chemicals. In recent years, microbial fermentations have been revolutionized by the application of genetically-engineered organisms. Many fermentations use bacteria but a growing number involve culturing mammalian cells.