Effects of C5 organic carbon and light on growth and cell activity of Haematococcus pluvialis under mixotrophic conditions

Abstract

Mixotrophic culture can be an effective way for increasing algae growth rate and productivity. In this study, the utilization of C5 organic carbon by Haematococcus pluvialis was investigated under mixotrophic conditions with different light intensities. H. pluvialis was found to have the capacity to assimilate ribose as a carbon source. Ribose supplementation increased biomass content and cell activity, which prolonged the green growing stage through increasing cell division. Higher cell activity levels also reduced the possibility of contamination. Forty one percent of supplemented ribose was assimilated after 7days under mixotrophic cultivation. In addition, cultures supplemented with ribose had an improved motile cell ratio (31%) over cultures supplemented with sodium acetate, 7%. Light intensities affected ribose assimilation and cell activity. The highest ribose assimilation level (46%) was obtained at high light intensity. However, the maximum ratio of motile cell (37%) and the highest total cell number (1.15×106/mL) occurred at low light intensity. The results provided information about the synergistic effects of light and types of C5 carbon on biomass growth for H. pluvialis under mixotrophic culture. The possibility of using ribose as a carbon source offers a new strategy for biomass improvement and contamination control under mixotrophic conditions.