Evaluation of metal stress on the composition of Ulva spp. biomass-for-biofuel.

Abstract

This work assesses the suitability of Ulva spp. as a biofuel crop. Since earlier research has demonstrated the relation between metal handling mechanisms and diverse changes in lipid content, we attempt to elucidate how lipids are stored within the cell by carrying out genetic expression studies and fluorescence microscopy. So far, Ulva thalli has been exposed to lead (Pb) and a combination of this metal with Buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, with the aim of comprehend the effects of lead on lipid content as well as the way they organise in the form of lipid droplets (LD). BSO was added to determine whether this caused changes in Ulva’s metal handling mechanisms. Results from fluorescence microscopy and genetic expression studies have showed that even though lead does not increase the amount of lipid in the cell, it causes changes in lipids localisation and dynamics. Moreover, it was observed that samples treated with BSO present fewer and smaller lipid droplets. To clarify BSO’s role in lipid droplet formation and get a better understanding of the pathways involved in heavy metal handling, further transcriptome and metabolic studies need to be performed. The elucidation of these mechanisms will ease biofuel production from macroalgal species like Ulva spp. This knowledge can be applied in countries like Mexico since Ulva and similar seaweed can be harvested in coastal areas around the world as a biofuel crop.