Combined effect of initial biomass density and nitrogen concentration on growth and astaxanthin production of Haematococcus pluvialis (Chlorophyta) in outdoor cultivation
|
Junfeng Wang1,2,a, Milton R. Sommerfeld1, Congming Lu2 and Qiang Hu1,*
|
1Laboratory for Algae Research and Biotechnology, College of Technology and Innovation, Arizona State University Polytechnic Campus, Mesa, AZ 85212, USA 2Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
|
|
|
|
| |
ABSTRACT |
Nitrogen availability and cell density each affects growth and cellular astaxanthin content of Haematococcus pluvialis, but possible combined effects of these two factors on the content and productivity of astaxanthin, especially under outdoor culture conditions, is less understood. In this study, the effects of the initial biomass densities IBDs of 0.1, 0.5, 0.8, 1.5, 2.7, 3.5, and 5.0 g L-1 DW and initial nitrogen concentrations of 0, 4.4, 8.8, and 17.6 mM nitrate on growth and cellular astaxanthin content of H. pluvialis Flotow K-0084 were investigated in outdoor glass column photobioreactors in a batch culture mode. A low IBD of 0.1 g L-1 DW led to photo-bleaching of the culture within 1-2 days. When the IBD was 0.5 g L-1 and above, the rate at which the increase in biomass density and the astaxanthin content on a per cell basis was higher at lower IBD. When the IBD was optimal (i.e., 0.8 g L-1), the maximum astaxanthin content of 3.8% of DW was obtained in the absence of nitrogen, whereas the maximum astaxanthin productivity of 16.0 mg L-1 d-1 was obtained in the same IBD culture containing 4.4 mM nitrogen. The strategies for achieving maximum Haematococcus biomass productivity and for maximum cellular astaxanthin content are discussed.
|
Key words:
astaxanthin; cell density; Haematococcus pluvialis; nitrogen; photobioreactor; outdoor culture |
|
|
|