You can also try nitrogen starvation to abolish protein and nucleic acids synthesis. Metabolism will remain active for synthesis of storage compounds. In general, it will work both for bacteria and microalgae. But depends on your final goal.

Retentostat cultivation has been especially developed to attain the non- growing, metabolically active state that you describe in your question. In the Delft Industrial Microbiology section, we analyse physiology and transcriptional regulation in retentostat cultures of S. cerevisiae; see publications bij Boender et al. in Applied and Environmental Microbiology, FEMS Yeast Research and Biochimica et Biophysica Acta - further work under review. Colleagues in the Kluyver Centre have used retentostats to study near-zero growth of Aspergillus niger and lactic acid bacteria.

Growth in retentostats should always be limited by the energy source.

Good luck,

Jack

Thank you all

Hiral, good suggestion but I am willing microbes uptaking C but not replicating. I'll take a look at antibiotics

Marco, I thought about this but it will be difficult to design the growth media (complex sources of N). It will involve media exchange

Jack, nice approach but I want them accumulating energy, the opposite effect.