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Coffee-cut stems are a potential fermentable sugars source, which can be upgraded in different valueadded products and energy vectors. Nevertheless, there are few reports focused on the acid pretreatment and saccharification processes. Thus, this paper evaluates the effect of the acid pretreatment and saccharification conditions of coffee cut-stems to find the highest sugar yield. Thereafter, the influence of the residence time in the acid pretreatment and the b-glucosidase supplementation in the saccharification process were analyzed. The combined severity factor and crystallinity index were used as metrics to evaluate both processes. In all assays, an increase in the crystallinity index was observed. Furthermore, a nonlinear trend of the combined severity factor respect to the residence time in the acid pretreatment was evidenced. The highest sugar yield was 66.75% with a combined severity factor of 1.84. The better saccharification process was achieved at combined severity factor of 2.01 with a digestibility of 43%. The addition of b-glucosidase in the enzymatic hydrolysis allows increasing the value to 69.07%. Hence, low temperatures, acid concentrations, and the b-glucosidase supplementation allows obtaining a high sugar yield from coffee cut stems.

Vanillin is widely known in the food industry as the main flavoring compound of vanilla. Its natural extraction from the seed is not enough to supply the worldwide vanillin demand. Therefore, new chemical routes from biomass have been developed to satisfy the vanillin market. A biorefinery for forest waste valorization could be an opportunity to maximize the economic gains and reduce the environmental impact in an integrated approach. This work demonstrates the experimental production of vanillin and vanillic acid through black liquor oxidation, after alkaline pretreatment of Eucalyptus grandis chips. Additionally, the remaining solid fraction was valorized by anaerobic digestion. The experimental yields in the oxidation stage were 4.37% and 2.14% (based on lignin) for vanillin and vanillic acid, respectively. The biogas productivity in anaerobic digestion was 163 mL/gVS. These values were the basis for the process simulation to analyze the potential for an integrated biorefinery. From an economic perspective, the process is feasible at a minimal processing scale of 8.58 ton/h. On the other hand, the environmental assessment concludes that the environmental impact is mainly affected by the CO2 and CH4 emissions from biogas upgrading.