Mixotrophic production of phycoerythrin and exopolysaccharide by the microalga Porphyridium cruentum

Abstract

The ability of the unicellular rhodophyte Porphyridium cruentum to grow mixotrophically on the soluble fraction of Solarium tuberosum meal was tested. At the beginning of stationary phase Porphyridium cruentum produced 7 μg ml −1 of phycoerythrin and 129 μg ml −1 of total soluble exopolysaccharide when cultured autotrophically. When cultured mixotrophically with the soluble fraction of Solanum tuberosum meal, the productivity increased to 10 μg ml −1 of phycoerythrin and 330 μg ml −1 of total soluble exopolysaccharide. When the soluble fraction of S. tuberosum meal was supplied together with nitrate and phosphate, the productivity of phycoerythrin increased to 21 μg ml −1 while the production of total soluble exopolysaccharide decreased to 195 μg ml −1. Results demonstrate that the soluble fraction of S. tuberosum meal can be used as substrate for the production of phycoerythrin and exopolysaccharide by P. cruentum improving the results obtained with the autotrophic culture medium.