Ethanol-enhanced biohydrogen production and metabolomic response in the green microalga Micractinium sp. KLSc62

Abstract

Hydrogen (H2) is recognized as a viable clean energy option due to its high energy density and minimal environmental impact. Green microalgae have garnered attention as a potential source of hydrogen production because of their ability to produce photosynthetic hydrogen and their environmental benefits. In a recent study, thirteen species of microalgae were screened for their growth potential and hydrogen production when supplemented with ethanol. Among the species evaluated, Micractinium sp. KLSc62 (initially named as G4) yielded the highest hydrogen production rate of 6090.5 ± 28.6 μmol mg⁻1 Chl with the supplementation of 30 mM ethanol over a 7-day period. Further analysis revealed that ethanol was utilized during H2 production process, leading to the formation of acetaldehyde as an intermediate before acetate was produced. Metabolic profiling identified 44 metabolites that were up- or down-regulated, categorized into four distinct groups. These findings highlight the potential of Micractinium sp. KLSc62 as an alternative energy producer and a promising candidate for future metabolite production in various chemical applications, emphasizing its utility as a cellular factory.