Combined resistance to oxidative stress and reduced antenna size enhance light-to-biomass conversion efficiency in Chlorella vulgaris cultures

Table 2 Photosynthesis and respiration rates

Parameters	WT	PG-14	SOR-1	SOR-5	SOR-6
Half-saturation intensity (μmol photons m⁻² s⁻¹)	110 ± 24^a	96 ± 41^a	128 ± 6^a	124 ± 9^a	118 ± 29^a
P_max (μmol O2 mg Chl⁻¹ h⁻¹)	96 ± 5^a	155 ± 11^b	146 ± 8^b	143 ± 7^b	150 ± 3^b
Respiration (μmol O2 mg Chl⁻¹ h⁻¹)	25 ± 3^a	43 ± 3^b	40 ± 5^b	47 ± 7^b	42 ± 6^b
Respiration (fmol oxygen cell⁻¹ h⁻¹)	6.4 ± 0.8^a	5.5 ± 0.4^a	5.2 ± 0.6^a	5.6 ± 0.8^a	5.4 ± 0.8^a
P_max/respiration (relative units)	3.9 ± 0.4^a	3.6 ± 0.2^a	3.7 ± 0.6^a	3.1 ± 0.5^a	3.6 ± 0.5^a

Parameters were measured on dark-adapted cell suspension of WT, PG-14 and SOR strains, upon 7 days of photoautotrophic growth in BG-11 medium in low light conditions (100 µmol photons m⁻² s⁻¹, 25 °C). O₂ evolution/consumption was measured with a Clark-type oxygen electrode (Oxygraph, Hansatech). Data are expressed as mean ± SD (n > 4). For each parameter measured, significantly different values among genotypes (ANOVA test, p < 0.05) are marked with different letters

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