1：Experimental Design and Method Selection:

The study investigated the effect of different light intensities (150 to 1100 μmol/m2/s) on cell growth and lutein production in the marine microalga Chlamydomonas sp. JSC4. The Haldane model was used to simulate growth kinetics. Carotenogenic gene expression was profiled using qRT-PCR under low (150 μmol/m2/s) and high (1100 μmol/m2/s) light conditions.

2：The Haldane model was used to simulate growth kinetics. Carotenogenic gene expression was profiled using qRT-PCR under low (150 μmol/m2/s) and high (1100 μmol/m2/s) light conditions. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: The microalgal strain Chlamydomonas sp. JSC4 was obtained from Professor Jo-Shu Chang. Cultures were grown in 1-L glass photobioreactors with Modified Bold Basal 3N medium. Samples were collected at the end of the experimental period when 90% of nitrate was consumed.

3：List of Experimental Equipment and Materials:

Equipment includes 1-L glass photobioreactor (length 15.5 cm, diameter 9.5 cm), fluorescent light source, LightCycler 96 Instrument (Roche), Direct-zolTM RNA MiniPrep kit (Zymo Research), SuperScript? III First-Strand Synthesis SuperMix (Invitrogen), SYBR? Premix Ex Taq? II (Tli RNaseH Plus) (Takara). Materials include Modified Bold Basal 3N medium, sea salt, CO2 gas.

4：5 cm, diameter 5 cm), fluorescent light source, LightCycler 96 Instrument (Roche), Direct-zolTM RNA MiniPrep kit (Zymo Research), SuperScript? III First-Strand Synthesis SuperMix (Invitrogen), SYBR? Premix Ex Taq? II (Tli RNaseH Plus) (Takara). Materials include Modified Bold Basal 3N medium, sea salt, CO2 gas. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Microalgae were cultivated at 28°C, pH 7.5, agitated at 500 rpm, aerated with 2.5% CO2 at 0.2 vvm. Light intensity was varied. Cell concentration was measured every 12 hours. Carotenoid, chlorophyll, and RNA samples were collected at experiment end. RNA extraction, cDNA synthesis, and qRT-PCR were performed as per protocols.

5：5, agitated at 500 rpm, aerated with 5% CO2 at 2 vvm. Light intensity was varied. Cell concentration was measured every 12 hours. Carotenoid, chlorophyll, and RNA samples were collected at experiment end. RNA extraction, cDNA synthesis, and qRT-PCR were performed as per protocols. Data Analysis Methods:

5. Data Analysis Methods: Biomass was determined using OD682 with a standard curve. Specific growth rate and productivity were calculated. qRT-PCR data were analyzed using the 2-ΔΔCt method with RPL32 as reference gene. Statistical analysis used two-tailed t-tests with p < 0.05 considered significant.