Nitrogen algal

Crude protein = %nitrogen X 6.25. Does not accurately reflect true protein content. Algal cells may contain nonprotein nitrogen substances, eg, 4—6% nucleic acids, dry wt basis. 

J. F. Witty, P. J. Keay, P. J. Frogatt, and P. J. Dart, Algal nitrogen fixation on temperate arable fields the Broadbalk experiment. Plant Soil 52 151-164 (1979). 

Procedure The Ascorbate peroxidase (EC 1.11.1.7) activity can be obtained by measuring the oxidation of ascorbate in the presence of H202. Grind the algal sample in liquid nitrogen and extract in 2.5 ml 50 mM potassium phosphate buffer (pH 7.0) containing 10% (w/v)... 

Procedure Harvest the algal cells by centrifugation at 3000 rpm for 5 min at 4°C, then, wash the cells in distilled water thrice. Prepare three replicates for each treatment. Sonicate the algal cells under nitrogen condition at 14 MHz for 10 min to extract the membrane fatty acids. Add 2 ml of 2 M KOH in 95% (v/v) methanol and 2 ml of benzene to the sonicated cells. Fill the headspace with N2 gas and incubate the mixture at 80°C for 3 h. On cooling, add an equal volume of methanol and extract the non-saponified fraction by... 

When we look at biological systems, the problem of re-release is particularly critical. In wastewater treatment Nitrogen control and Phosphorous control have been identified as critical elements in preventing algal blooms downstream from wastewater treatment plants. Part of the problem in designing the wastewater process is control of the re-release of these compounds. Nitrogen can be reduced back to a gas, but Phosphorous has to be treated by precipitation to remove it Irom the wastewater stream. The same is true for almost any of the heavy toxic metals such as Arsenic, Lead, Copper, Uranium, and Cadmium to name a few. Safe to say, this is also a common problem with phyto-remediation systems. 

The inefficiency of microbial heterotrophy does have a side benefit as it enhances nutrient remineralization rates. This serves to increase the availability of inorganic nitrogen and phosphorus for the photoautotrophs. The multiple roles of bacteria in the marine food web were shown in Figure 23.2, with the component of the food web controlled by the algal herbivores depicted on the left side and the microbial loop on the right. The viral shunt acts on both pathways. 

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