Two lignin revalorization processes were proposed in this thesis to produce highadded
value bulk chemicals. Revalorization process schemes were composed of three
stages: lignin extraction, lignin purification and lignin depolymerization. Extraction
and purification processes were the same for the two proposals. Lignin extraction
was studied in the sense of the enhancement of lignin production as well as trying to
extract lignin with optimum physicochemical properties for its valorization. To this
end, different extraction methods were studied and the one that gave the best
results was optimized. Purification process objective was to obtain specific lignin
fractions with different characteristics so they can be used in their most adequate
application. Different purification processes (differential precipitation and
ultrafiltration) were considered with this purpose. Ultrafiltration was selected as the
purification process that produced lignin fractions with different purity, specific
molecular weight and defined physicochemical properties.