TABLE 1.

Carbon recovery and electron balance of A. succiniciproducens raw-whey batch fermentation in the presence of high CO₂ levels^a

Substrate or product	Substrate concn (mol/100 mol)	Carbon concn (mol)	Available hydrogen concn
			mol of H/mol	mol of H/100 mol of lactose
Substrates
Lactose	100	1,200	48	4,800
Lactic acid	3	9	11	33
CO2	346	346	0	0
Products
Succinic acid	243	972	14	3,402
Acetic acid	111	222	8	888
Formic acid	47	47	2	94

^aCarbon and electron balance were determined as described by Zeikus et al. (34), except the carbon and electron balance in cells was not included. CO₂ was supplied as magnesium carbonate (35 g/liter). Note that 80% of the carbon (moles) and 92% of the available hydrogen (moles of hydrogen per 100 moles of lactose) were recovered.