%0 Articles
%T Valorization of non-traditional lignocellulosic feedstocks for bioenergy and biorefinery applications
%A Papamatthaiakis, Nikolaos
%D 2026
%J Dissertationes Forestales
%V 2026
%N 399
%R doi:10.14214/df.399
%U http://dissertationesforestales.fi/article/26017
%X ​Biomass is considered an abundant renewable resource for energy production through established routes such as combustion, biochemical conversion, and industrial energy systems. These applications could benefit from diversified feedstocks and provide a clear understanding of how different conversion processes influence fuel quality and the potential of side-stream products. Emerging technologies and developing markets may enhance the effective valorization of newly introduced resources, maximize their uses and profitability, and reduce the environmental footprint. At present, comparative data on non-traditional lignocellulosic feedstocks under region-specific conditions are scarce, and such data could further support a better-established acceptance of bioenergy. This thesis evaluates herbaceous perennial energy crops, coffee by-products, and native hardwood species from Brazil, with emphasis on their suitability for bioenergy and biorefinery applications. In <b>Paper I</b>, giant knotweed (<em>Fallopia sachalinensis</em> var. Igniscum’) and Virginia mallow (<em>Sida hermaphrodita</em>) were assessed for their capacity for pellet production under Nordic conditions, combining field data and physical and chemical analyses. The results for bulk density, moisture, energy content, and elemental composition were in line with certification schemes, but mechanical durability and ash require further investigation. <b>Paper II</b> examined how hydrothermal liquefaction (HTL) could benefit coffee by-products by improving combustion properties and producing chemicals with potential and value-added applications. The hydrochars showed higher energy content than the raw materials, containing chemically complex oil fractions rich in fatty acids and alkaloids. <b>Paper III</b> evaluates native hardwood species from the Brazilian Cerrado - Caatinga transition zone, without prior evidence existing about their industrial energy applications. Forest inventory distribution data, dendrometry characteristics, and combustion-relevant fuel property measurements were used to identify species with favorable tree capacity and combustion properties. The thesis provides comparative information on non-traditional biomass resources and conversion routes, suggesting new additions in feedstock portfolios for bioenergy and biorefinery development.