Evaluation of light-driven ATP production and interspecies comparison of thylakoid membranes isolated from vegetable leaves

Agricultural byproducts generated during crop production represent a largely untapped biomass resource with significant potential for sustainable valorization. Thylakoid membranes (TMs), abundant in chloroplast-rich leaves, function as natural photosynthetic platforms that convert light energy into adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide phosphate (NADPH), key biological “energy currencies”. In this study, isolated TMs exhibited light-dependent energy conversion activity, achieving ATP and NADPH rates of 5.73 ± 0.14 and 8.13 ± 1.22 μM min⁻¹ μg⁻¹ chlorophyll (Chl), respectively, with NADPH production requiring the addition of 5 μM ferredoxin to sustain electron transfer. ATP production remained active for up to 32 h under illumination and 7 d in darkness, while NADPH generation persisted for 16 h and 24 h under light and dark conditions, respectively. Comparative analysis of 15 vegetable byproducts leaves identified stem lettuce leaves ( Lactuca sativa var. Angustata as) as the optimal source, producing higher ATP yields than spinach ( Spinacia oleracea L. ). Mechanistically, TMs from stem lettuce leaves contained lower levels of free fatty acids and α -linolenic acid than those from spinach, which minimized membrane disruption and enhanced proton motive force generation. The findings identify stem lettuce leaves as an efficient and low-cost feedstock for isolating functional TMs, underscoring the potential of agricultural byproducts as renewable resources for bioenergy conversion, industrial bioprocessing, and circular bioeconomy applications. • Thylakoid membranes (TMs) were successfully isolated from 15 vegetable byproduct leaves. • Stem lettuce TMs exhibited the highest ATP yield among tested sources. • Reduced free fatty acids in stem lettuce TMs enhanced membrane stability and proton motive force. • Vegetable byproducts, especially stem lettuce residues, represent low-cost feedstocks for TM-based bioenergy and biomanufacturing applications.