Assessment and comparison of thermochemical pathways for the rice residues valorization: pyrolysis and gasification.

Lignocellulosic biomass conversion applying thermochemical routes has been postulated as an alternative for generating renewable energy. This research compares energy-driven biorefineries based on two thermochemical routes addressed to upgrade rice husk and rice straw produced in the Department of Sucre-Colombia. Initially, this research analyzes the physico-chemical and structural characterization of the rice residues. Four different scenarios were proposed to compare the energy-driven biorefineries based on fast pyrolysis and gasification considering technical, economic, and environmental metrics. These biorefineries were simulated using the Aspen Plus V.14.0 software. The novelty of this research is focused on the identification of the biorefinery with the best techno-economic, energetic, and environmental performance in the Colombian context. Economic and environmental analyses were done by using economic metrics and emissions. From an economic perspective, the stand-alone gasification process did not have a positive economic margin. In contrast, the fast pyrolysis process has the best economic performance since this process has a positive profit margin. Indeed, scenario 1 (fast pyrolysis of both rice residues) presented an economic margin of 13.75% and emissions of 2170.92 kgCO2eq/kg for 10 years. However, this scenario was not energetically the best, holding second place due to the feedstock requirements, compared to gasification. The biorefinery scenario 1 has the best performance.

Development and characterization of dual-modified yam (Dioscorea rotundata) starch-based films.

The current consumer demand for fresh food and the interest in caring for the environment have driven the development of biodegradable film packaging to replace synthetic films to preserve the integrity of food. The objective of this work was to evaluate the effects of starch modifications (oxidized, cross-linked, and dual: oxidized/cross-linked), starch concentration (1 and 2%), and glycerol concentration (5 and 15%) on water vapor permeability (WVP), mechanical properties (tensile strength and elongation), optical, and structural properties of films based on "hawthorn" yam starch. The WVP of the films was 4.4 × 10-10 to 1.5 × 10-9 g/m∗s∗Pa, where the films with oxidized yam starch showed a 58.04% reduction concerning the native starch. The tensile strength of oxidized yam starch films showed a decrease of 17.51% with an increase in glycerol concentration. For the 1% starch concentration, elongation increased by 17.03% when the glycerol concentration was increased from 5 to 15%. Modification of starch, starch concentration, and glycerol have a significant effect on the barrier, mechanical, physical, and structural properties of films made with yam starch, where films made with oxidized yam starches at a concentration of 1% starch and 5% glycerol showed the best responses of the properties evaluated.

Caracterización de harinas y almidones de batatas (Ipomoea batatas Lam.) de la costa caribe colombiana / Characterization of batatas flours and starches (Ipomoea batatas Lam.) from the colombian caribbean coast

RESUMEN El cultivo de batata en Colombia registra pocos excedentes para el mercado nacional, su rendimiento se encuentra en aproximadamente 5t/ha. Dicha producción, se centra en la región Caribe colombiana, en los departamentos de Córdoba y Sucre; sin embargo, el cultivo de la batata podría llegar a ocupar un lugar de importancia para la agroindustria, por los aportes nutricionales y por su alto contenido de almidón, considerado ideal para la obtención industrial de harinas y almidones. En esta investigación, se determinaron las propiedades estructurales y funcionales de harinas y almidones, obtenidos de cuatro variedades de batata, cultivadas en la región Caribe colombiana. Las propiedades funcionales analizadas fueron la capacidad de absorción de agua, amilosa, viscosidad máxima, temperatura de gelatinización, asentamiento, estabilidad y el comportamiento estructural, que fue estudiado mediante espectroscopia de infrarrojo FT-IR. Los resultados presentaron variaciones en los genotipos y las localidades evaluadas; los viscoamilograma en harina mostraron valores alentadores para la industria, tanto la viscosidad máxima (300cP) como el breakdown (-15,64cP) y setback (186,65cP), mientras los almidones presentaron valores relativamente altos, por lo cual, se recomienda realizar técnicas de modificación a la estructura nativa del almidón, modificaciones físicas, enzimáticas o químicas, para ampliar sus aplicaciones. El comportamiento estructural mostró señales que indican la presencia de grupos OH, CH, CO, H2O en las harinas y almidones, de batata evaluados.

ABSTRACT The production of sweet potatoes in Colombia presents few surplus for the domestic market, its performance is approximately 5t/ha, with a sown area of barely 5 hectares; this production is obtained on few areas of the national agricultural region (Caribbean region, specifically in the departments of Córdoba and Sucre). However, the crop could reach an important place in the agro-industry, not only for the nutritional contributions but also because of its high content of starch, considered ideal for the industrial production of flours and starches. This research identified the structural and functional properties of flours and starches obtained from four varieties of sweet potato grown in the Colombian Caribbean region. The functional properties analyzed were the capacity of absorption of water, amylose, maximum viscosity, temperature of gelatinization, settlement, stability and structural behavior which was studied by FT-IR-infrared spectroscopy. Results presented variations in genotypes and localities evaluated, the viscoamilogram in flour showed encouraging values for the industry, both the maximum viscosity (300 cP), the breakdown (cP -15.64) and setback (186,65 cP), while starches showed relatively high values, therefore it is recommended to perform modification techniques to the native structure of the starch (physical, chemical or enzymatic modifications) to expand its applications. The structural behaviour showed signs indicating the presence of groups OH, CH, CO, H2O in evaluated flours and sweet potato starches.

Hidrólisis enzimática de residuos de la cosecha de caña de azúcar / Hydrolysis Enzymatic of crop residues sugar cane

En esta investigación, se hidrolizó un sustrato deslignificado proveniente de residuos de la cosecha caña de azúcar (hojas y cogollos) usando un preparado enzimático con 27.53 unidades de papel filtro (FPU), obtenido a partir de enzimas comerciales. La hidrólisis se llevó a cabo a un pH de 4.2 y una temperatura de 50 oC. Fueron analizados modelos de inhibición por sustrato, glucosa e inhibición total por producto. Los resultados mostraron que los modelos que mejor se ajustan a los datos experimentales, son los modelos de inhibición competitiva por glucosa, con una constante de Michaelis (Km) de 20.37 g/L, velocidad máxima (Vmax) 39 g/L h y una constante de inhibición (ki) de 0.442. En el caso que las relaciones enzima – Sustrato (E/S) sean mayores de 0.5, se puede aplicar el modelo cinático de Michaelis-Menten.

In this research, a delignified substrate from crops residues sugar cane residues (leaves and top cane) was hydrolyzed using an enzyme preparation with 27.53 FPU. This enzyme was obtained from trade. Hydrolysis was carried out to pH of 4.2 and a temperature of 50 oC. Models of inhibition models substrate, glucose and total inhibition product was analyzed. The results showed that models that best fit the data experimental was the models competitive glucose inhibition (Km= 20.37, Vmax=39 and ki= 0.442). In the event that E/S is above 0.5, can applied kinetic models of Michaelis – Menten.