EFFECT OF AMMONIUM CONCENTRATION ON THE GROWTH OF RECOMBBVANT PICHIA PASTOKIS AND EXPRESSION OF ANGIOSTATIN / 微生物学通报

ABSTRACT

Fed-batch cultures of recombinant Rchia pastoris were conducted for production of angiostatin. The whole fermentation included a growth phase on glycerol and an expression phase on methanol. When ammonium hydroxide solution was used to adjust pH, the cell growth during the expression phase was inhibited and the highest angiostatin concentration was 9.08 mg/L. Shake-flask cultures were carried out in media containing different quantities of ammonia. The results showed that ammonia had an obvious inhibition effect on the cell growth during the expression phase. Therefore KOH solution was used to adjust pH, and during the expression phase cells were able to grow and the highest angiostatin concentration reached 20 mg/L.