Lincomycin A is a clinically important antibiotic produced by Streptomyces lincolnensis that is used against gram-positive bacteria. To increase the yield of lincomycin A, a calcium gluconate feeding strategy was studied in a 15 L bioreactor. The results showed that the addition time of calcium gluconate was optimal during the late fermentation process to ensure a higher yield of lincomycin A. The optimum addition was continuous feeding at a speed of 0.0638 g/L/h from 111 to 158 h, which can increase the lincomycin A titer to 9160 mg/L, 41.3% higher than that without gluconate feeding. Enzyme activities of the central metabolic pathways, accumulation of intermediate metabolites, NADPH and NADH concentrations, and NADPH/NADH ratio were determined to investigate the mechanism of enhanced lincomycin A production by calcium gluconate addition. The activities of key enzymes of the pentose phosphate pathway (PPP) (glucose 6-phosphate dehydrogenase) and TCA cycle (isocitrate dehydrogenase) were enhanced by approximately twofold. A higher ratio of NADPH/NADH was observed in the fermentation process with the optimized feeding strategy providing sufficient reducing power. These data indicated that more flux flows through the PPP and the TCA cycle to provide more precursors, ATP and reducing power to support the synthesis of lincomycin A. The results showed a new strategy to improve the production of lincomycin A by manipulating the flux through the PPP and the TCA cycle.

中文翻译：

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饲喂葡萄糖酸钙可增强林肯链霉菌发酵中的林可霉素A的产生

林可霉素A是林肯链霉菌产生的临床上重要的抗生素用于抵抗革兰氏阳性细菌。为了增加林可霉素A的产量，研究了在15 L生物反应器中添加葡萄糖酸钙的策略。结果表明，在后期发酵过程中，葡萄糖酸钙的添加时间是最佳的，以确保林可霉素A的更高产量。最佳添加是在111至158 h时以0.0638 g / L / h的速度连续进料，这可以将林可霉素A滴度提高至9160 mg / L，比不添加葡萄糖酸盐时高41.3％。确定中央代谢途径的酶活性，中间代谢物的积累，NADPH和NADH的浓度以及NADPH / NADH的比例，以研究添加葡萄糖酸钙增强林可霉素A产生的机理。戊糖磷酸途径（PPP）（6-磷酸葡萄糖脱氢酶）和TCA循环（异柠檬酸脱氢酶）的关键酶的活性提高了约两倍。在发酵过程中观察到较高的NADPH / NADH比，采用优化的进料策略可提供足够的还原力。这些数据表明，有更多的助焊剂流过PPP和TCA循环，从而提供了更多的前体，ATP和还原能力，从而支持了林可霉素A的合成。结果表明，通过控制通过林通霉素的通量来提高林可霉素A产量的新策略PPP和TCA周期。在发酵过程中观察到较高的NADPH / NADH比，采用优化的进料策略可提供足够的还原力。这些数据表明，有更多的助焊剂流过PPP和TCA循环，从而提供了更多的前体，ATP和还原能力，从而支持了林可霉素A的合成。结果表明，通过控制通过林通霉素的通量来提高林可霉素A产量的新策略。 PPP和TCA周期。在发酵过程中观察到较高的NADPH / NADH比，采用优化的进料策略可提供足够的还原力。这些数据表明，有更多的助焊剂流过PPP和TCA循环，从而提供了更多的前体，ATP和还原能力，从而支持了林可霉素A的合成。结果表明，通过控制通过林通霉素的通量来提高林可霉素A产量的新策略。 PPP和TCA周期。