Dissolved oxygen profiles in photosynthetic microbial slimes

Prediction of dissolved oxygen and carbon dioxide concentration profiles in tubular photobioreactors for microalgal culture

A model is developed for prediction of axial concentration profiles of dissolved oxygen and carbon dioxide in tubular photobioreactors used for culturing microalgae. Experimental data are used to verify the model for continuous outdoor culture of Porphyridium cruentum grown in a 200-L reactor with 100-m long tubular solar receiver. The culture was carried out at a dilution rate of 0.05 h-1 appl...

Dissolved oxygen levels alter gene expression and antigen profiles in Borrelia burgdorferi.

The Lyme disease spirochete, Borrelia burgdorferi, encounters many environmental signals as it cycles between the arthropod vector and mammalian hosts, including temperature, pH, and other host factors. To test the possibility that dissolved oxygen modulates gene expression in B. burgdorferi, spirochetes were exposed to differential levels of dissolved oxygen, and distinct alterations were obse...

Steady-state axial profiles of dissolved oxygen in tall bubble column bioreactors

A model is developed for prediction and interpretation of the observed steady-state axial dissolved oxygen concentration profiles in tall bubble columns. The observed concentration profiles are non-linear, unlike what would be expected if the hydrostatic pressure alone influenced the profiles. The non-linear profiles result from the axial mixing of liquid in the column. Several other factors in...

Photosynthetic generation of oxygen.

The oxygen in the atmosphere is derived from light-driven oxidation of water at a catalytic centre contained within a multi-subunit enzyme known as photosystem II (PSII). PSII is located in the photosynthetic membranes of plants, algae and cyanobacteria and its oxygen-evolving centre (OEC) consists of four manganese ions and a calcium ion surrounded by a highly conserved protein environment. Re...

Counting viruses and bacteria in photosynthetic microbial