A synthetic medium for bacterial cellulose production by Acetobacter xylinum subsp sucrofermentans

Of several organic nitrogen sources tested, corn steep liquor (CSL) was found to be the most suitable for cellulose production by Acetobacter xylinum subsp. sucrofermentans BPR 2001. When lactate, which was detected only in CSL, was added to culture media containing other nitrogen sources, cellulose production was stimulated to levels similar to that in CSL medium. Lactate was found to stimulate cell growth during the early stage of culture and shown to function by linking with the respiratory chain and generating energy for growth. Therefore, it was speculated that lactate acts as an accelerator driving the TCA cycle as well as an energy producer, resulting in high cellulose production and rapid cell growth. The effects of various amino acids were also investigated: L-methionine was found to be essential for high cellulose yields and stimulation of cell growth during the early stage of culture. On the basis of these observations, a defined synthetic medium, containing lactate and methionine, was formulated, with which cellulose production of 90% of that with the CSL medium was reached in jar fermenter cultures.