Screening of Astaxanthin-Hyperproducing Haematococcus pluvialis Using Fourier Transform Infrared (FT-IR) and Raman Microspectroscopy.

Haematococcus pluvialis has promising applications owing to its ability to accumulate astaxanthin under stress conditions. In order to acquire higher astaxanthin productivity from H. pluvialis, it is critical not only to develop efficient mutagenesis techniques, but also to establish rapid and effective screening methods which are highly demanded in current research and application practice. In this work, we therefore attempted to develop a new approach to screening the astaxanthin-hyperproducing strains based on spectroscopic tools. Using Fourier transform infrared (FT-IR) and Raman microspectroscopy, we have achieved rapid and quantitative analysis of the algal cells in terms of astaxanthin, β-carotene, proteins, lipids, and carbohydrates. In particular, we have found that the ratio of the IR absorption band at 1740 cm-1 to the band at 1156 cm-1 can be utilized for identifying astaxanthin-hyperproducing strains. This work may therefore open a new avenue for developing high-throughput screening methods necessary for the microbial mutant breeding industry.