Continuous production of poly(3-hydroxyalkanoates) by Pseudomonas oleovorans in a high-cell-density, two-liquid-phase chemostat

Accumulation of Poly[( R )-3-Hydroxyalkanoates] in Pseudomonas oleovorans during Growth with Octanoate in Continuous Culture at Different Dilution Rates

“…mcl-PHAs are hydrophobic polyesters and are attracting increasing interest for their possible application as biologically produced and inherently biodegradable substitutes for conventional plastic materials (6,8,10,20,32). Particularly, when subjected to nitrogen limitation in batch (22, 24) and chemostat culture (17,33,34), P. oleovorans has been reported to accumulate high cellular mcl-PHA contents.The nature and availability of essential nutrients are important parameters in determining the extent of storage compound accumulation in P. oleovorans (23,24). Generally, the production of microbial cell mass is limited by the restricted availability of a particular nutrient.…”

Two-stage continuous process development for the production of medium-chain-length poly(3-hydroxyalkanoates)

“…It was shown that P. oleovorans could be grown in continuous long-term cultivations. A high-cell-density chemostat of P. oleovorans was operated for 1 month with stable productivity (Preusting et al, 1993), a finding that would also probably apply to the two-stage continuous system presented here. Such a long-term production system might allow for reduced maintenance/operation compared with fed-batch cultures, which have to be started periodically.…”

“…Improving the accumulation rate has the advantage that the resources put into the system are optimally converted to product. However, with a content of 62% PHA, a high cellular product level had already been achieved, and opportunities for a further increase in specific PHA accumulation rate are limited (Preusting et al, 1993). Improvements in productivity by increasing biomass are limited by the fact that increases in volumetric PHA productivity are not proportional to increases in biomass.…”

Controlled regioselectivity of fatty acid oxidation by whole cells producing cytochrome P450BM-3 monooxygenase under varied dissolved oxygen concentrations

“…Further improvements are likely to be based on the acceleration of intracellular cofactor regeneration and better substrate uptake. We expect that with appropriate recombinant strains productivities similar to those found in vitro will ultimately be obtained, and that by using about 10-fold higher cell densities in batch conversions (Riesenberg et al, 1991;Wubbolts et al, 1996) or by applying this system in continuous cultures (Preusting et al, 1993;), the production of the desired long-chain hydroxy fatty acids in g to kg amounts will become practicable.…”