The effect of CO2" on the synthesis and activation of Bacillus licheniformis MC14 alkaline phosphatase has been shown by the development of a defined minimal salts medium in which this organism produces 35 times more (assayable) alkaline phosphatase than when grown in a low-phosphate complex medium or in the defined medium without cobalt. Stimulation of enzyme activity with cobalt is dependent on a low phosphate concentration in the medium (below 0.075 mM) and continued protein synthesis. Cobalt stimulation resulted in alkaline phosphate production being a major portion of total protein synthesized during late-logarithmic and early-stationary-phase culture growth. Cells cultured in the defined medium minus cobalt, or purified enzyme partially inactivated with a chelting agent, showed a 2.5-fold increase in activity when assayed in the presence of cobalt. Atomic spectral analysis indicated the presence of 3.65 ± 0.45 g-atoms of cobalt associated with each mole of purified active alkaline phosphatase. A biochemical localization as a function of culture age in this medium showed that alkaline phosphatase was associated with the cytoplasmic membrane and was also found as a soluble enzyme in the periplasmic region and secreted into the growth medium.

Diamond like carbon (DLC) films were deposited by plasma enhanced chemical vapour deposition, whose purpose is in the application of the films to further improve read/write durability of next generation recording discs. The effects of acetylene (C 2 H 2 ) and ethylene (C 2 H 4 ) source gases and deposition parameters on roughness, structure, hardness, resistivity, silicone contamination, glide performance and microcorrosion measurement on the cobalt concentration of DLC films are studied utilising the following equipment: AFM, Raman, nanoindenter, resistivity gauge meter, phase metrics, time of flight SIMS and inductively coupled plasma mass spectroscopy. Results show that the Raman I d /I g ratio, G and D peak wavenumber, hardness, glide noise and avalanche, silicone contamination and cobalt concentration of the C 2 H 4 source gas films are significantly lower than those of C 2 H 2 gas. Diamond like carbon films prepared at the higher gas flow exhibit a lower I d /I g and cobalt concentration. Films deposited with a higher voltage bias and heater power will induce a higher I d /I g and cobalt concentration.