Production Of Phycobiliproteins Research Articles

Two-Stage Mass Cultures of Cyanobacteria for the Production of Carotenoids and Phycobiliproteins

Two-Stage Mass Cultures of Cyanobacteria for the Production of Carotenoids and Phycobiliproteins

Enhancement of phycobiliprotein production in nitrogen-fixing cyanobacteria

Summary The influence of several environmental factors on the phycobiliprotein content of two phycoerythrin-rich nitrogen-fixing cyanobacteria has been studied in order to maximize pigment production. Total phycobiliprotein content was enhanced when either temperature within the optimum range for growth or cell density of the culture was increased. The phycobiliprotein level increased also in response to a decrease in irradiance. In all cases the effect was more marked for C-phycoerythrin than for C-phycocyanin and allophycocyanin. The cellular content in C-phycoerythrin was also preferentially enhanced when cultures were irradiated with green light. On the other hand, red light induced an increase in the C-phycocyanin content, but the C-phycoerythrin level decreased considerably.

Spectral Response Curves for the Formation of Phycobiliproteins, Chlorophyll and δ-Aminolevulinic Acid in Cyanidium caldarium

Summary Spectral response curves for the formation of phycobiliproteins and the chlorophyll both show maxima at 440, 575 and 645 nm in cells of the wild-type mutant III-D-2 of Cyanidium caldarium . Chlorophyll formation occurs maximally in about 460 and 645 nm light in the phycobiliprotein-less mutint III-C. The chlorophyll-less mutant GGB forms phycobiliproteins maximally when illuminated with 440 nm light and a much smaller response peak occurs at 575 nm. These data indicate that there is one photoreceptor-biosynthetic system for chlorophyll formation and another for phycobiliprotein production. One is defective in GGB and another in III-C. In the wild-type-like mutant III-D-2, where spectral response curves for the two classes of tetrapyrrolic pigments are qualitatively indistinguishable, the two biosynthetic paths may be linked through common intermediates whose synthesis is regulated by light. The synthesis of δ-aminolevulinic acid is maximally promoted by about the same wavelengths of light which stimulate chlorophyll or phycobiliprote in synthesis. - This spectral similarity may be caused by removal of feedback inhibitors or by a synchronous formation of various pigment synthesizing enzymes. Glucose represses δ-aminolevulinic acid and chlorophyll formation in dark-grown cells of strain III-D-2. These compounds form in darkness after heterotrophically grown cells are washed free of glucose. However, the cells produce no phycobiliproteins in darkness regardless of whether glucose is present or not. Together with results from other experiments, this observation inferes that phycobiliprotein formation requires control mechanisms besides the regulation of ALA synthesis.