Abstract:

Metabolic flux analysis model of β-carotene in Spirilina was established based on data of cell composition, flux distribution of Spirilina cultured at different temperatures was analyzed according to this model. Analysis results showed that temperature has an obvious effect on β-carotene metabolic flux, and when cultured at 33℃ the flux is maximum. Activities of 11 enzymes in β-carotene biosynthesis pathway of Spirilina cultured at a temperature gradient were measured, and then correlation and components analysis were used to investigate the regulation controlls of these enzymes to β-carotene metabolic flux. Subsequently, a new parameter Cci was constructed to reflect these controlls based on correlation and components analysis, which is very similar to the metabolic control coefficient. The results showed that ribulose-1,5-bisphosphate carboxylase (CcRuBisCO=0.296), glucse-6-phosphate dehydrogenase (CcG6PD=0.23) and pyruvate dehydrogenase (CcPDHC=0.221) have higher control coefficient, indicating that they play primary roles in control of flux, however, the coefficients of α-ketoglutaric dehydrogenase (Ccα-KGDHC=－0.102), phosphoglyceromutase (CcPGM=－0.081) and isocitrate dehydrogenase (CcICDH=－0.074) are negative, conformed that they have negative control to flux.

Key words: β-carotene, temperature, enzyme activity, metabolic regulation control, principal component analysis