Pretratamiento fúngico de biomasa de Agave lechuguilla Torr. para la producción de etanol

Recientemente la biomasa del cogollo de Agave lechuguilla ha sido establecida como materia prima con potencial para la producción de etanol, sin embargo, el alto gasto energético en el pretratamiento requiere la búsqueda de métodos que lo minimicen y propicie una mejora en la factibilidad económica del proceso. En comparación con las tecnologías tradicionales, el pretratamiento biológico ofrece una alternativa en la que las enzimas de remoción de la lignina son capaces de desdoblar las estructuras complejas de la misma, sin el uso de químicos y con menor gasto energético. En este trabajo se probó el uso de Phanerochaete chrysosporium H-298 en la biomasa de Agave lechuguilla. Los dos factores ensayados para la optimización del proceso fueron el tiempo de incubación y la concentración de la fuente de nitrógeno. Los resultados mostraron una máxima deslignificación (36.15 %), se preservó la celulosa sin cambios significativos. Las condiciones óptimas de pretratamiento fueron: 60 días de incubación y una concentración de nitrógeno de 1M. La hidrólisis enzimática del material pretratado con el complejo enzimático Cellic® CTec3 mostró una máxima liberación de glucosa de 44.9 g L-1 a las 92 horas, con rendimiento de hidrólisis de 93.09 %, mayor al obtenido en la hidrólisis de la muestra sin pretratar (37.92 %). La concentración de etanol a las 10 horas de fermentación fue de 16.53 g L-1 (equivalente a una concentración >2 % v/v de etanol) con 5.7 g L-1 de glucosa remanente a ese tiempo de incubación

Early Optimization Stages of Agave lechuguilla Bagasse Processing toward Biorefinement: Drying Procedure and Enzymatic Hydrolysis for Flavonoid Extraction

Agave lechuguilla agro-waste is a promising renewable material for biorefining purposes. The procurement of added-value co-products, such as bioactive phytochemicals, is required to improve bioprocesses and promote the bio-based economy of the productive areas of Mexico. In this study, we aimed to evaluate the effect of post-harvest management and enzymatic pretreatment as the first stages of the A. lechuguilla valorization process. Four drying methods were compared, and enzymatic hydrolysis was optimized to obtain a flavonoid-enriched extract applying ultrasound-assisted extraction. In both experiments, the total phenolic (TPC) and flavonoid (TFC) contents, HPLC-UV flavonoid profiles, and radical scavenging capacity (DPPH) were considered as response variables. The results demonstrated that light exposure during the drying process particularly affected the flavonoid content, whereas oven-dehydration at 40 °C in the dark preserved the flavonoid diversity and antioxidant functionality of the extracts. Flavonoid glycoside recovery, particularly anthocyanidins, was 1.5–1.4-fold enhanced by enzymatic hydrolysis using the commercial mix Ultraflo© under optimized conditions (pH 4, 40 °C, 180 rpm, and 2.5 h) compared to the unpretreated biomass. The extraction of flavonoids from A. lechuguilla bagasse can be carried out using a scalable drying method and enzymatic pretreatment. This study confirmed the potential of this agro-waste as a source of marketable natural products

High Throughput Profiling of Flavonoid Abundance in Agave lechuguilla Residue-Valorizing under Explored Mexican Plant

Agave lechuguilla waste biomass (guishe) is an undervalued abundant plant material with natural active compounds such as flavonoids. Hence, the search and conservation of flavonoids through the different productive areas have to be studied to promote the use of this agro-residue for industrial purposes. In this work, we compared the proportion of total flavonoid content (TFC) among the total polyphenolics (TPC) and described the variation of specific flavonoid profiles (HPLC-UV-MS/MS) of guishe from three locations. Descriptive environmental analysis, using remote sensing, was used to understand the phytochemical variability among the productive regions. Furthermore, the effect of extractive solvent (ethanol and methanol) and storage conditions on specific flavonoid recovery were evaluated. The highest TPC (16.46 ± 1.09 GAE/g) was observed in the guishe from region 1, which also had a lower normalized difference water index (NDWI) and lower normalized difference vegetation index (NDVI). In contrast, the TFC was similar in the agro-residue from the three studied areas, suggesting that TFC is not affected by the studied environmental features. The highest TFC was found in the ethanolic extracts (6.32 ± 1.66 QE/g) compared to the methanolic extracts (3.81 ± 1.14 QE/g). Additionally, the highest diversity in flavonoids was found in the ethanolic extract of guishe from region 3, which presented an intermedia NDWI and a lower NDVI. Despite the geo-climatic induced variations of the phytochemical profiles, the results confirm that guishe is a valuable raw material in terms of its flavonoid-enriched bioactive extracts. Additionally, the bioactive flavonoids remain stable when the conditioned agro-residue was hermetically stored at room temperature in the dark for nine months. Finally, the results enabled the establishment of both agro-ecological and biotechnological implications