Fig. 5: SgRNA clones with improved L-lactate tolerance.

a Volcano plot showing enrichment of 75 sgRNAs during cultivation with added 0.1 M sodium L-lactate after 32 d, (threshold: log₂ fold-change ≥ 2, −log₁₀ p-value ≥ 20). Only 8 sgRNAs were enriched in a 0.1 M NaCl control cultivation. b Eight genes where both sgRNAs were enriched above average in 0.1 M L-lactate cultivation (coloured) but not NaCl cultivation (gray). Color indicates association to a cyanobase pathway. F - mean fitness score of two sgRNAs. c Mean growth rate µ (h⁻¹) of selected, reconstructed knockdown strains (n = 2 independent replicate cultivations) over the first 80 h of batch cultivation with L-lactate added to 0.1 M. Symbols show significance between the control strain (NT0) and mutants using 1-sided student’s t-test. *p-value ≤ 0.05, **p-value ≤ 0.01 (sll1712, p = 0.019; bcp2, p = 0.006), #—only 1 replicate was used for ilvA mutant. d Example of growth advantage in batch culture with L-lactate added to 0.1 M of sgRNA clones bcp2, aroH, and ilvA. e Absorption spectra of fastest-growing sgRNA mutants and NT0 in 0.1 M L-lactate. Arrows mark absorption maxima for pigments. CT carotenoids, PC phycocyanin, CA chlorophyll A. f Relative pigment absorption for carotenoids, phycocyanin, and chlorophyll A for the selected strains with L-lactate added to 0.1 M. Source data underlying Fig. 5a, b are provided as a Source Data file.