RESUMEN

The extraction of nanocellulose from agro-industrial wastes is feasible due to a significant amount of cellulose contained in these natural fibers. The analysis of chemical treatments effects on the fibers to obtain the nanocellulose must be taken into consideration for the definition of an adequate and efficient methodology. In this study, two alkaline treatments were used (cleaning and bleaching), as well as an acid treatment for the extraction of nanocellulose from corn straw residues. The samples were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), dynamic light scattering (DLS) and atomic force microscopy (AFM) to verify the action and modifications caused in their chemical and physical structures. It was possible to verify the extraction of hemicellulose and lignin, the reduction of fiber sizes to the nanoscale, and the final sample presenting superior crystallinity for the bleached fiber.

RESUMEN

The effect of natural mineral on the mono-digestion of maize straw was evaluated in continuously stirred tank reactors (CSTRs) at 38 °C. Different strategies of mineral addition were studied. The organic loading rate (OLR) was varied from 0.5 to 2.5 g volatile solid (VS) L(-1) d(-1). A daily addition of 1 g mineral L(-1) in reactor 2 (R2) diminished the methane production by about 11 % with respect to the initial phase. However, after a gradual addition of mineral, an average methane yield of 257 NmL CH4 g VS(-1) was reached and the methane production was enhanced by 30 % with regard to R1. An increase in the frequency of mineral addition did not enhance the methane production. The archaeal community was more sensitive to the mineral than the bacterial population whose similarity stayed high between R1 and R2. Significant difference in methane yield was found for both reactors throughout the operation.

Asunto(s)

Reactores Biológicos , Metano/biosíntesis , Zea mays , Archaea/efectos de los fármacos , Bacterias/efectos de los fármacos , Metano/química , Minerales/química , Minerales/farmacología , Residuos

RESUMEN

The present work aimed to study some aspects of sorption and immobilization of cellulase molecules on soil components by the analysis of the reactions of cellulase in a soil treated with different levels of maize residue and incubated for 90 days. The analysis of variance showed that the effects of the treatments of maize straw, incubation time and their interaction on cellulase adsorption, desorption and immobilization were statistically significant. The adsorption and immobilization capacities of soil by application of maize straw increased significantly. However they decreased with decreasing the soil organic matter (SOM) after 45 days of incubation. The desorption of adsorbed cellulase molecules from the soil by washing with distilled water depended on the SOM contents and its humification. The binding strength of cellulase molecule with fresh miaze straw was significantly stronger than that with humified maize straw. The immobilized cellulase activity, particularly its specific activity increased significantly by increasing the OC contents in the soil treated with maize straw.