A. Quesadachanto et al., MICROBIAL-PRODUCTION OF PROPIONIC-ACID AND VITAMIN-B-12 USING MOLASSES OR SUGAR, Applied microbiology and biotechnology, 41(4), 1994, pp. 378-383
With a cell concentration of 125 g dry biomass 1(-1) and a dilution ra
te of 0.1 h -1, Propionibacterium acidipropionici produces 30 g propio
nic acid 1(-1) from sugar with a productivity of 3 g1(-1) h (-1). The
yield of propionic acid is approx. 0.36-0.45 g propionic acid g-l sucr
ose and is independent of the dilution rate and cell concentration. Ac
etic acid is an unwanted by-product in the production of propionic aci
d. The concentration of acetic acid only increases slightly when the c
ell concentration is increased. A two-stage fermentation process was d
eveloped for the conversion of sugar or molasses of various types to p
ropionic acid and vitamin B-12. By fermentation of blackstrap molasses
(from sugar beet and sugar cane) in the first fermentation stage 17.7
g propionic acid 1(-1) with a yield of 0.5 g propionic acid g(-1) car
bohydrate was produced with a dilution rate of 0.25 h(-1). In the seco
nd stage 49 mg vitamin B-12 1(-1) was produced at a dilution rate of 0
.03 h(-1).