| Abstrak/Abstract |
The potential of local microalgae, Euglena sp., a biological agent for alternative carotenoid production,
has not been widely studied. Photoperiod and nitrogen starvation in the batch culture cultivation system
were the main determining factors in many studies to increase carotenoid production in microalgae.
Their application needs to be studied in Euglena sp. This study aimed to measure the growth and profiles
of chlorophyll and carotenoid levels and to verify the expression of carotenoid biosynthetic-related
genes in Euglena sp. with nitrogen starvation continued with photoperiod and nutrient starvation
treatment of the medium. This study showed that the long photoperiod treatment for 18 hours and
nutrient starvation in Euglena sp. gave different results on each day of cultivation and the type of
treatment on growth parameters, chlorophyll content, carotenoid content and the type of carotenoid
production. Long photoperiod and nutritional starvation treatments gave the highest growth values,
chlorophyll content, and carotenoid levels on days 10 and 11. This study also analysed the expression
of carotenoid biosynthetic-related genes, which showed several essential findings, namely the face of
the carotenoid biosynthesis gene ECrtE (Geranyl Geranyl diphosphate synthase), ECrtB (Phytoene
Synthase), and CYP97H1 (β-carotene hydroxylase) were associated with upregulated expression with
long photoperiod and starvation treatment with the highest upregulation results on day 9 of rearing in
Euglena sp. The relative gene expression of ECrtB (Phytoene Synthase) and CYP97H1 (β-carotene
hydroxylase) is a critical gene in the carotenoid biosynthetic pathway of Euglena sp. Long-photoperiods
for 18 hours and nutrient starvation are essential factors in the success of Euglena culture to produce
high total carotene to improve the potential of microalgae as biological agents in the needs of carotene
compounds. |
