Development of chemically defined media for Lactococcus lactis subsp. lactis YF11 to eliminate the influence of...

Chemically defined media (CDM) can eliminate or lessen the interference that occurs in complex culture media (CCM) caused by the undefined substrate pools, and various CDM have been designed and employed for investigating microbial physiology and multiomics. Herein, using the measured amount of total amino acids in CCM and combined with the in vivo and in vitro amino acid content of Lactococcus lactis subsp. lactis YF11, new enriched CDM were designed and then optimized using a statistical design-of-experiment method coupling with fed-batch fermentation to eliminate or lessen the influence of hyperosmotic pressure. Cell volume was introduced as a target index to assess the performance of CDM, and average osmotic pressure (AOP) was employed to describe the osmotic pressure of CDM. The AOP was significantly decreased from 610 mOsm/kg·H₂O in the initial CDM (I-CDM) to 360 mOsm/kg·H₂O in fed-batch CDM (F-CDM), and the cell volume was increased from 0.142 ± 0.004 μm³ in I-CDM to 0.198 ± 0.008 μm³ in F-CDM, which was close to 0.206 ± 0.005 μm³ found in CCM, indicating that the strategy of designing and improving CDM followed by a statistical design-of-experiment coupling with fed-batch cultivation presented a promising pathway for extensive utilization of CDM.

The online version contains supplementary material available at 10.1007/s13205-023-03788-5.