Comparative assessment of environmental impacts of 1st generation (corn feedstock) and 3rd generation (carbon dioxide feedstock) PHA production pathways using life cycle assessment.

Polyhydroxyalkanoates (PHA) are bio-based and biodegradable alternatives to conventional plastic types and have the potential to reduce the environmental impacts along the life cycle. In comparison to already established production routes for PHA (heterotrophic production) based on renewable feedstock like glucose (first generation feedstock), novel production routes, such as the photoautotrophic production of PHA based on CO as feedstock (third generation feedstock) could offer new perspectives with regard to the reduction in the environmental impacts. To quantify the environmental impacts of PHA produced via photoautotrophic and heterotrophic production pathways, life cycle assessment (LCA) methodology based on ISO 14040/44 was applied, thus conducting a first of its kind comparative study for PHA based on third generation feedstock.

Glycogen, poly(3-hydroxybutyrate) and pigment accumulation in three strains when exposed to a stepwise increasing salt stress.

The cyanobacterial genus is of particular interest to science and industry because of its efficient phototrophic metabolism, its accumulation of the polymer poly(3-hydroxybutyrate) (PHB) and its ability to withstand or adapt to adverse growing conditions. One such condition is the increased salinity that can be caused by recycled or brackish water used in cultivation. While overall reduced growth is expected in response to salt stress, other metabolic responses relevant to the efficiency of phototrophic production of biomass or PHB (or both) have been experimentally observed in three strains at stepwise increasing salt concentrations.

PHB Producing Cyanobacteria Found in the Neighborhood-Their Isolation, Purification and Performance Testing.

Cyanobacteria are a large group of prokaryotic microalgae that are able to grow photo-autotrophically by utilizing sunlight and by assimilating carbon dioxide to build new biomass. One of the most interesting among many cyanobacteria cell components is the storage biopolymer polyhydroxybutyrate (PHB), a member of the group of polyhydroxyalkanoates (PHA). Cyanobacteria occur in almost all habitats, ranging from freshwater to saltwater, freely drifting or adhered to solid surfaces or growing in the porewater of soil, they appear in meltwater of glaciers as well as in hot springs and can handle even high salinities and nutrient imbalances.

In situ based surface-enhanced Raman spectroscopy (SERS) for the fast and reproducible identification of PHB producers in cyanobacterial cultures.

The production of polyhydroxybutyrate (PHB) by autotrophic fermentation of cyanobacteria has received increasing interest in the light of carbon emission reducing process strategies. Biotechnological approaches are in development to optimize the yield of PHB, including adapted cultivation media, characterized by a limitation of key nutrients: cyanobacteria accumulate PHB as energy storage molecules under limited growth conditions. Since there is an increasing demand for fast, simple and reliable analytics, we report the establishment of surface enhanced Raman spectroscopy (SERS) as a suitable monitoring tool for up scaled PHB production processes.

Novel unexpected functions of PHA granules.

Polyhydroxyalkanoates (PHA), polyesters accumulated by numerous prokaryotes in the form of intracellular granules, have been for decades considered being predominantly storage molecules. However, numerous recent discoveries revealed and emphasized their complex biological role for microbial cells. Most of all, it was repeatedly reported and confirmed that the presence of PHA granules in prokaryotic cells enhances stress resistance and robustness of microbes against various environmental stress factors such as high or low temperature, freezing, oxidative, and osmotic pressure.