Strategy for the analysis of lignocellulosic biomass to select a viable transformation route in the Colombian context.

Lignocellulosic biomass is widely available in the world. However, a consensus has yet to be established to evaluate the biomass valorization alternatives. The chemical composition is the primary technical limitation in selecting a transformation route to obtain value-added products. In this paper, the bagasse from non-centrifuged sugar (NCS) production and Pinus patula (PP) wood chips were analyzed in terms of complete chemical composition to establish their potential for selecting the transformation routes. A strategy to select the best route based on the chemical composition was applied and a feedstock criteria model was proposed. Schemes were obtained and compared using a bioprocess selection strategy proposed in previous works. As a result, the preliminary biorefinery schemes were finally defined. The assessment of schemes derived from the outlined strategy included technical, economic, environmental, and social analyses. The environmental evaluation was complemented with a geolocation assessment, revealing a 0.75-ton CO2-eq/yr contribution to the carbon footprint for local distribution. The sustainability index for the PP biorefinery and the bagasse from NCS production was analyzed, resulting in indices of 44.8 and 60.9, respectively. These values were primarily derived from the economic and environmental analyses of both processes.

Designing a cocktail containing redox enzymes to improve hemicellulosic hydrolysate fermentability by microorganisms.

Bioproducts production using monomeric sugars derived from lignocellulosic biomass presents several challenges, such as to require a physicochemical pretreatment to improve its conversion yields. Hydrothermal lignocellulose pretreatment has several advantages and results in solid and liquid streams. The former is called hemicellulosic hydrolysate (HH), which contains inhibitory phenolic compounds and sugar degradation products that hinder microbial fermentation products from pentose sugars. Here, we developed and applied a novel enzyme process to detoxify HH. Initially, the design of experiments with different redox activities enzymes was carried out. The enzyme mixture containing the peroxidase (from Armoracia rusticana) together with superoxide dismutase (from Coptotermes gestroi) are the most effective to detoxify HH derived from sugarcane bagasse. Butanol fermentation by the bacteria Clostridium saccharoperbutylacetonicum and ethanol production by the yeast Scheffersomyces stipitis increased by 24.0× and 2.4×, respectively, relative to the untreated hemicellulosic hydrolysates. Detoxified HH was analyzed by chromatographic and spectrometric methods elucidating the mechanisms of phenolic compound modifications by enzymatic treatment. The enzyme mixture degraded and reduced the hydroxyphenyl- and feruloyl-derived units and polymerized the lignin fragments. This strategy uses biocatalysts under environmentally friendly conditions and could be applied in the fuel, food, and chemical industries.