Influence of inorganic salts on biomass production, biochemical composition, and bioethanol production of Populus alba

Abstract

Inorganic salts are very important for the biosynthesis of major components such as cellulose and lignin. In order to investigate biomass production, major components of the biosynthesis of plant cell wall and the bioethanol production of Populus alba, we examined the effect of inorganic salts on in vitro culture systems without specific mineral salts. The medium without H2PO4 was supportive for Populus alba shoot growth, while the absence of NH4+ resulted in poor shoot growth. The medium without H2PO4- and Fe3+ inhibited aboveground biomass production, whereas NH4+ and K+ deprivation led to an enhancement of the same. The root/shoot ratio of Populus alba in the medium without H2PO4 was high compared with plants cultured in the control medium. H2PO4 is deeply involved in lignin biosynthesis, and its removal has been shown to reduce the biosynthesis of lignin. Plants grown on nitrate-free medium were found to be good for enzymatic saccharification and ethanol production. The plants grown in the medium without NO3- showed 72.0% enzyme digestibility, and the yield of ethanol showed 9.58% ethanol productivity after 12 hours. These results can be used as the basis for producing high-quality biomass for future bioethanol production.