Synergistic Regulation of Metabolism by Ca2+/Reactive Oxygen Species in Penicillium brevicompactum Improves Production of Mycophenolic Acid and Investigation of the
Ca2+ Channel
posted on 2021-12-23, 18:35authored byMianhui Chen, Jingjing Wang, Lin Lin, Xiangyang Xu, Wei Wei, Yaling Shen, Dongzhi Wei
Although Penicillium
brevicompactum is a very important industrial strain
for mycophenolic acid production,
there are no reports on Ca2+/reactive oxygen species (ROS)
synergistic regulation and calcium channels, Cch-pb. This study initially
intensified the concentration of the intracellular Ca2+ in the high yielding mycophenolic acid producing strain NRRL864
to explore the physiological role of intracellular redox state in
metabolic regulation by Penicillium brevicompactum. The addition of Ca2+ in the media caused an increase
of intracellular Ca2+, which was accompanied by a strong
increase, 1.5 times, in the higher intracellular ROS concentration.
In addition, the more intensive ROS sparked the production of an unreported
pigment and increase in mycophenolic acid production. Furthermore,
the Ca2+ channel, the homologous gene of Cch1, Cch-pb,
was investigated to verify the relationship between Ca2+ and the intracellular ROS. The Vitreoscilla hemoglobin was overexpressed, which was bacterial hemoglobin from Vitreoscilla, reducing the intracellular ROS concentration
to verify the relationship between the redox state and the yield of
mycophenolic acid. The strain pb-VGB expressed the Vitreoscilla hemoglobin exhibited a lower intracellular
ROS concentration, 30% lower, and decreased the yield of mycophenolic
acid as 10% lower at the same time. Subsequently, with the NRRL864
fermented under 1.7 and 28 mM Ca2+, the [NADH]/[NAD+] ratios were detected and the higher [NADH]/[NAD+] ratios (4 times higher with 28 mM) meant a more robust primary
metabolism which provided more precursors to produce the pigment and
the mycophenolic acid. Finally, the 10 times higher calcium addition
in the media resulted in 25% enhanced mycophenolic acid production
to 6.7 g/L and induced pigment synthesis in NRRL864.