Effects of Glucose Assimilation on Lutein and Chlorophyll Biosyntheses in the Green Alga Chlorella pyrenoidosa

摘要

Glucose assimilation caused a significant decrease of lutein and chlorophyll accumulation in Chlorella pyrenoidosa cultivated in low nitrogen medium, which are in line with the previously reported glucose-bleaching effect on the green alga Chlorella protothecoides cultivated in nitrogen deficient medium. Our study showed that an excessive lipid production induced by nitrogen deficiency was expected to be responsible for the decrease of lutein and chlorophyll accumulation in C. pyrenoidosa under heterotrophic conditions. When C. pyrenoidosa was cultivated in high nitrogen medium, the lutein and chlorophyll biosyntheses acted very differently: lutein content still decreased markedly whereas chlorophyll content remained stable. In addition, when we inhibited chlorophyll biosynthesis with levulinic acid, the chlorophyll a (chl a) and chlorophyll b (chl b) contents decreased markedly, but the lutein biosynthesis was not influenced at all. It was concluded that lutein and chlorophyll biosyntheses were possibly not coordinated in C. pyrenoidosa under heterotrophic conditions.