Impact of CO2 Sparging on Growth of Haematococcus Pluvialis and Astaxanthin Production

Abstract

Haematococcus pluvialis is known to accumulate secondary ketocarotenoid astaxanthin, a potent antioxidant. Production of astaxanthin from H. pluvialis can be achieved in a two stage process, where first step involves the production of high quantity of biomass followed by its induction to accumulate astaxanthin. High quantity of biomass was achieved by inclusion of carbon dioxide sparging in the growth medium. Growth measurements showed increase in cell number and chlorophyll content with CO2 sparging in the medium. Owing to increase in photosynthetic activity led to increase in biomass production. Indoor conditions produce of 0.387 mg/L biomass with carbon dioxide sparging. Accumulation of astaxanthin was induced by addition of salicylic acid and ferrous sulphate. Biochemical studies of the culture upon induction indicated presence of unfavourable conditions. Treatment with 200 μM of Salicyclic acid and 450 μM of ferrous sulphate gave highest astaxanthin accumulation of 0.868 mg/L, which was 54% higher than the astaxanthin obtained in the untreated cells of Haematococcus. Microscopic observation of treated Haematococcus cells also showed the increased accumulation of astaxanthin. It was observed that accumulation of astaxanthin is associated with environmental and nutritional stresses, which may cause interference in the normal cell division of Haematococcus.