Biomass production of four Cynara cardunculus clones and lignin composition analysis

Four Cynara cardunculus clones, two from Portugal and two from Spain were studied for biomass production and their lignin was characterized. The clones differed in biomass partitioning: Spanish clones produced more capitula (54.5% vs. 43.9%), and Portuguese clones more stalks (37.2% vs. 25.6%). The heating values (HHVo) of the stalks were similar, ranging from 17.1 to 18.4 MJ/kg, Lignin was studied by analytical pyrolysis (Py-GC/MS(FID)), separately in depithed stalks (stalks(Dp)) and pith. Stalks(Dp) had in average higher relative proportions of lignin derived compounds than pith (23.9% vs. 21.8%) with slightly different lignin monomeric composition: pith samples were richer in syringyl units as compared to Stalks(Dp) (64% vs. 53%), with S/G ratios of 2.1 and 1.3, respectively. The H:G:S composition was 7:40:53 in Stalks(Dp) and 7:29:64 in pith. The lignin content ranged from 18.8% to 25.5%, enabling a differentiation between clones and provenances. (C) 2015 Elsevier Ltd. All rights reserved.