Extraction of short-chain-length poly-[(R)-hydroxyalkanoates] (scl-PHA) by the "anti-solvent" acetone under elevated temperature and pressure.

A novel method was developed for extraction of short-chain-length poly(hydroxyalkanoates) (scl-PHA) from microbial biomass by the well-known "scl-PHA anti-solvent" acetone at elevated temperature and pressure in a closed system combining components for extraction, filtration, and product work-up. Recovery of scl-PHA using this new approach was compared with established methods using chloroform at ambient pressure. The new method performs similar regarding product purity (98.

Polyhydroxyalkanoate production from whey by Pseudomonas hydrogenovora.

Whey permeate from dairy industry was hydrolyzed enzymatically to cleave its main carbon source, lactose, to glucose and galactose. The hydrolysis products were chosen as carbon sources for the production of poly-3-hydroxybutyric acid (PHB) by Pseudomonas hydrogenovora. In shaking flask experiments, the utilization of whey permeate as a cheap substrate was compared to the utilization of pure glucose and galactose for bacterial growth under balanced conditions as well as for the production of PHB under nitrogen limitation.

Potential of various archae- and eubacterial strains as industrial polyhydroxyalkanoate producers from whey.

Three different microbial wild-type strains are compared with respect to their potential as industrial scale polyhydroxyalkanoate (PHA) producers from the feed stock whey lactose. The halophilic archaeon Haloferax mediterranei as well as two eubacterial strains (Pseudomonas hydrogenovora and Hydrogenophaga pseudoflava) are investigated. H.

Assessment of formal and low structured kinetic modeling of polyhydroxyalkanoate synthesis from complex substrates.

A formal kinetic mathematical model for poly-(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)] terpolyester synthesis from glucose and galactose derived from whey permeate supplemented with gamma-butyrolactone by the archaeon Haloferax mediterranei was created. Further, a low structured mathematical model for poly-3-hydroxybutyrate synthesis from whey permeate by Pseudomonas hydrogenovora was developed. In both cases, biosyntheses for obtaining the experimental data used for compiling the models were performed via fed-batch cultivations.

Production of polyhydroxyalkanoates from agricultural waste and surplus materials.

To be competitive with common plastics, the production costs of polyhydroxyalkanoates (PHAs) have to be minimized. Biotechnological polymer production occurs in aerobic processes; therefore, only about 50% of the main carbon sources and even a lower percentage of the precursors used for production of co-polyesters end up in the products wanted. A second cost factor in normally phosphate-limited production processes for PHAs is the costs for complex nitrogen sources.