Purpose: To investigate the effect of ammonium salts and fermentation pH on the biosynthesis of
acarbose by
Streptomyces M37.
Methods: Different ammonium salts were added to the fermentation broth of
Streptomyces
M37 to
explore their effects on acarbose production. The concentration and addition time of ammonium salts,
and the fermentation pH on acarbose biosynthesis were investigated. To study the effect of pH on
acarbose yield, the activities of glutamate dehydrogenase (GDH) and glucose-6-phosphate
dehydrogenase (G6PDH) were also studied.
Results: The optimal supplemental concentration and addition time of NH
4Cl were 0.1 M and 72 h,
respectively. Regulation of pH at 8.5 until the stationary phase was reached favoured acarbose
production. Furthermore, GDH and G6PDH exhibited higher activity at pH 8.5 than at other pHs.
Increase in acarbose yield was 53.4 % (compared with control) by NH
4Cl, and was approximately 5460
mg/L.
Conclusion: The results suggest that the addition of NH
4Cl and maintenance of fermentation pH at 8.5
for 72 h after inoculation was an effective strategy for enhancing acarbose biosynthesis.
