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[Display omitted] • Combined micro-current and salt stresses promoted lipid production of Chlorella vulgaris. • Periodic micro-current enhanced algal growth and carbon flow distribution to lipid production. • Increased activities of antioxidant and lipid-regulation enzymes contributed to lipid synthesis. • Current and salinity successively favored fatty acid composition for biodiesel production. Two-stage cultivation of Chlorella with periodic micro-current coupled with NaCl stress was investigated to analyze the performance and contribution of increased lipid production. In the growth stage, periodic micro-current of 3 mA resulted in an escalation of 290.06 mg/L of Chlorella's biomass by 61.25 % in comparison to the control. During the induction stage, under a NaCl concentration of 8 g/L, the highest lipid content and yield attained were 42.11 % and 199.32 mg/L, revealing an increment of 53.13 % and 39.11 % respectively when compared to the control. Additionally, the polyunsaturated fatty acids content (PUFA) decreased from 30.11 % to 23.09 %, while the saturated fatty acids content (SFA) increased from 31.86 % to 42.39 %. Chlorella demonstrated adaptability to the alterations in the cultivation environment by an initial upsurge and later a reduction in SOD and CAT enzyme activities, and concurrently facilitated lipid synthesis by similar changes in the activities of ACCase and DGAT. The above cultivation enabled a synergistic effect of swift growth and efficient lipid accumulation in Chlorella , providing groundwork for large-scale biofuel production. [ABSTRACT FROM AUTHOR]

[Display omitted] • ARTP-ethanol co-mutation for synchronous enhancement of lipid and astaxanthin. • Improved key enzyme activity, gene expression for lipid and astaxanthin biosynthesis. • Elucidated mechanisms of lipid and astaxanthin accumulation by ARTP and ethanol. • Upregulation of genes nubpl , Abcc 2, PAO related to lipid and astaxanthin accumulation. Haematococcus lacustris is a precious algal species renowned for its ability to simultaneous production of astaxanthin and lipid. However, its slow growth rate necessitates the development of appropriate mutagenesis methodologies to effectively enhance its synchronous production of both astaxanthin and lipid. This study introduced the co-mutation of Atmospheric and Room Temperature Plasma (ARTP) and ethanol. The performance and preliminary mechanisms underlying the combined accumulation of astaxanthin and lipid in H. lacustris under both mutations by ARTP and ethanol were comparatively analyzed. Combined astaxanthin and lipid contents relative to total cell mass in the 110–2 strain reached 54.4%, surpassing that of strain 0–3 and the control by 17.0% and 47.6% respectively. Transcriptome level analysis revealed how both ethanol and ARTP induction promote the expressions of carotenoid and lipid synthesis genes and related enzymatic activities. Upregulation of genes associated with cell activity contributed to lipid and astaxanthin metabolism in multi pathways. [ABSTRACT FROM AUTHOR]