Abstract:In this work, the microorganism concentration, HA yield, HA molecular weight and molecular weight distribution of hyaluronic acid (HA) wereanalyzed at different pH and temperature in 5 L bioreactor and 250 mL shake flask. It was found that the best pH for bacteria growth and HA production was 7.00, but under HA synthesis stage, HA generation rate was higher at higher pH condition 8.00. Two regulation styles, the periodic control mode and subsection control mode were designed. The results were as follows: the periodic control mode had no effect to HA yield and HA molecular weight, subsection control mode had no effect to HA yield, but could impove the molecular weight by 10.60% and significantly reduced the dispersion coefficient, and at periodic control mode when culture temperature was 33 ℃，HA molecular weight when harvested was 18.70% higher than temperature 37 ℃. These results could provide directions for subsequent industrialization production molecular weight concentrated HA and reducing the separation cost of HA with different molecular weights.
