Improving phytosterol biotransformation at low nitrogen levels by enhancing the methylcitrate cycle with transcriptional regulators PrpR and GlnR of Mycobacterium neoaurum.

Improvement in phytosterol biotransformation after the enhancement of propionyl-CoA metabolism through the combined modifications of the prp operon and glnR of mycobacteria was investigated for the first time. The overexpress of prpR in MNR can increase the transcription of essential genes (prpC, prpD and prpB) of MCC, reduce the intracellular propionyl-CoA level and improve bacterial viability. The knockout of glnR can enhance the adaptability of MNR to the nitrogen source. In the MNRΔglnR strain, overexpress of prpR can achieve efficient production of AD at low nitrogen levels, thus reducing the production cost. This strategy provides a reference for the economic and effective production of other valuable steroid metabolites from phytosterol in the pharmaceutical industry.