Development of Axenic Culture and Astaxanthin Production in Microalgae

Abstract

Microalgae are a renewable natural resource that requires only sunlight, carbon dioxide, phosphorus, and nitrogen for rapid growth. They produce a broad variety of basic chemical substances―such as vitamins, fatty acids and carotenoids－that have high added value potential for the pharmaceutical and food industries. The aim of this study was to develop axenic culture and to establish a cell growth assay for microalgae. A further experiment was carried out to determine the yield of astaxanthin derived from microalgae. The axenic culture was developed using a mixture of antibiotics [ampicillin (100 μg/ml), streptomycin (10 μg/ml), chloramphenicol (10 μg/ml), penicillin (10 μg/ml), neomycin (50 μg/ml), gentamycin (50 μg/ml), kanamycin (10 μg/ml), and nystatin (1.5 μg/ml)] and then used to extract a variety of useful components from the microalgae. The optimal concentration for the antibiotic mixture was 1-3 percent. A spectrophotometric cell growth assay was also established. Astaxanthin was extracted from Haematococus lacustris with a yield of 1.9×10-3 μg/l per 1 ml of culture medium. In conclusion, the axenic culture method developed here allows extraction of high-quality astaxanthin and other useful components from microalgae.