 Even the most acid-tolerant "Clostridium" strains can produce vinegar in concentrations of only a few per cent, compared to "Acetobacter" strains that can produce vinegar in concentrations up to 20%.At present, it remains more cost-effective to produce vinegar using "Acetobacter", rather than using "Clostridium" and concentrating it.As a result, although acetogenic bacteria have been known since 1940, their industrial use is confined to a few niche applications.