Dual-carbon/nitrogen limitation

Low level phosphate (0.5-5.Og/L) in a chemically defined medium is required for maximum CA yield. The presence of excess phosphate leads to a decrease in carbon dioxide fixation, an increase in the formation of certain sugar acids, and growth stimulation. Kubicek and Rohr (1977) showed that CA accumulated whenever phosphate was exhausted even when nitrogen was not limited. Nevertheless, chemostat cultures performed under dual phosphate/nitrogen limitation produced results very similar to those from a nitrogen-limited culture. ... 

It was shown a few years ago that PHA-accumulating bacteria are able to grow in chemostat cultures limited simultaneously by carbon and nitrogen substrates (Dumer et al. 2(X)1), a growth regime which is principally not possible in batch culture. It was concluded that dual (C, N) limited growth offers a new approach to tailor the PHA composition during biosynthesis because all carbon substrates are consumed to completion (Zinn et al. 2001, 2004). 

---