Abstract:

Changes in extracellular, intracellular and total adenine concentration during the inosine fermentation process
were determined by HPLC. Results showed that the total adenine concentration in fermentation broth did not vary
significantly. The main factors that affected inosine yield in the fermentation process were ratio between intracellular and
extracellular adenine of yeast cells in the culture medium and extracellular adenine concentration. After sterilization,
60%—70% of the amount of adenine was released to the outside of the cells and 30%—40% remained inside. Extracellular
adenine was fundamental to bacterial growth during the early fermentation stage, and a higher amount of adenine released to
the outside of the cells favored bacterial growth and inosine accumulation. Intracellular adenine in yeast cells was the key to
reaching and maintaining suboptimal levels of adenine during the middle and later fermentation stages. The suboptimal level
of adenine in this study was 31.92 mg/L.

Key words: HPLC, adenine, Bacillus subtilis, inosine fermentation