The Impacts of Ozone Inhibition on the Growth of Bacteria on Biomass Production of Haematococcus lacustris in Mixotrophic Cultivation

Abstract

Mixotrophic culture can improve the growth of Haematococcus lacustris, an alga that can produce the high-value carotenoid astaxanthin. However, these conditions make the culture susceptible to bacterial contamination. Ozone gas was therefore investigated for its ability to inhibit the growth of heterotrophic bacteria during the mixotrophic cultivation of H. lacustris. The concentration and flow rate of ozone were then optimized. While the flow rate had no significant effect, an ozone concentration of 0.4 mg/L allowed algal growth but inhibited bacterial growth. Additionally, different wavelengths of light exposure were used to enhance algal growth and biomass production, and red light showed the highest increase, followed by blue light. The addition of 0.08 mg/L ozone to light exposure improved growth for both red and blue light. In mixotrophic culture using sodium acetate as a carbon source, the same concentration of ozone improved growth compared to untreated mixotrophic culture or to pure autotrophic culture.

Keywords

Ozone / Mixotrophy / Haematococcus lacustris / Antibacterial

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