Identification of Rhodosorus marinus isolated in Taiwan and study on its optimum culture conditions.

This study aims to identify a local red microalga in Taiwan through morphology and molecular phylogeny. Then, to determine the optimal culture conditions, as in temperature, light intensity and light quality, for the mass production of B-phycoerythrin using the microalga, growth and pigment content of the microalga under different cultivation conditions were studied with two-factor experiments. The microalga was cultivated at four temperatures (16, 20, 24 and 28 ℃) and under three light intensities (20, 60 and 100 μmol photons m−2 s−1) to study the interaction effect of temperature and light intensity. The microalga was also cultivated at the mentioned temperatures under white, red, green and blue lights to study the interaction effect of temperature and light quality. The cell number, relative index of chlorophyll, and relative index of phycoerythrin (RIPE) were analysed by flow cytometry. After morphological and molecular phylogenetic analyses, the species was identified as Rhodosorus marinus. When studying the effect of temperature and light intensity, the R. marinus cultivated at 20–24 ℃ under a light intensity of 100 μmol photons m−2 s−1 produced high cell number and RIPEs. Using the optimal light intensity for cell number accumulation, R. marinus cultivated under white light at 20–28 ℃ produced high cell number and RIPEs. In conclusion, this study showed that a temperature of 20–24 ℃ with 100 μmol photons m−2 s−1 of white light can promote growth in R. marinus and produce cell number containing the highest phycoerythrin contents. [ABSTRACT FROM AUTHOR]