【摘要】 实验考察了富马酸酶活抑制剂放线菌酮对米根霉发酵产L-苹果酸和富马酸的影响.结果表明,发酵16h加入浓度15mg/L的放线菌酮使米根霉富马酸酶胞质同功酶比活力峰值降低48.7%,而苹果酸脱氢酶胞质同功酶活力却未有明显改变,生成的富马酸比对照样减少37.1%,而L-苹果酸积累量提高54.6%,达到21.7g/L.表明通过对米根霉富马酸酶胞质同功酶的抑制作用能减弱米根霉积累富马酸代谢途径中由L-苹果酸向富马酸的转化,从而促进米根霉积累L-苹果酸.更多还原

【Abstract】 The effects of fumarase inhibitor cycloheximide on fermentation of L-malic acid and fumaric acid by Rhizopus oryzae ME-M15 were investigated.The results showed that the addition of cycloheximide(15 mg/L) during the acid production stage after 16 h incubation greatly affected the metabolism of Rhizopus oryzae ME-M15.The activity of cytosolic isoenzyme of fumarase was decreased markedly by 48.7%, but the activity of NAD-malate dehydrogenase in the cytosol fraction did not change significantly in the presence of cycloheximide.Fumaric acid production was severely decreased in the presence of cycloheximide with 37.1% in comparison with the control mycelium.In contrast to the inhibitory effect of fumaric acid fermentation, the addition of cycloheximide caused the increase of L-malic acid accumulation to 21.7 g/L, which was 54.6% higher than that of the control.The analyses revealed that the inhibition of fumarase isoenzyme in the cytosol fraction could reduce the metabolic flux from L-malic acid to fumaric acid in the pyruvate carboxylation pathway(cytosolic pathway), promoting the L-malic acid accumulation by Rhizopus oryzae ME-M15.更多还原