Many different
succinic acid producing Gram-negative bacteria have been isolated
in various anaerobic environments such as domestic sludge,
cattle waste, rice paddy, marine shipworm, mouth of dog, rumen
and gastro-intestines. To date, the bacteria isolated from the
rumen, including A. succinogenes and M. succiniciproducens,
are the best candidates for succinic acid production as they produce
succinic acid as a major fermentation product. This is most
likely due to that the rumen is a highly efficient organ providing
an environment to produce succinic acid. The rumen is a
unique microbial ecosystem found in many species of herbivorous
mammals known as ruminants. The primary role of the
rumen is to allow pre-gastric digestion of various polysaccharide
materials, which is mediated by a great diversity of rumen
microorganisms, consisting of 109–1010 bacterial, 105–106 protozoan
and 103–104 fungal cells ml−1 of rumen fluid