ABSTRACT
The transformation of biomasses from agro-industrial waste can significantly impact the production of green chemicals from sustainable resources. Pectin is a biopolymer present in lignocellulosic biomass as Orange Peel Waste (OPW) and has possibilities for making platform compounds such as furfural for sustainable chemistry. In this work, we studied the transformation to furfural of OPW, pectins, and D-galacturonic acid (D-GalA), which is the main component (65 wt%) of pectin. We analyzed pectins with different degrees of esterification (45, 60 and 95 DE) in a one-pot hydrolysis reaction system and studied the differences in depolymerization and dehydration of the carbohydrates. The results show that the production of furfural decreases as the DE value increases. Specifically, low DE values favor the formation of furfural since the decarboxylation reaction is favored over deesterification. Interestingly, the furfural concentration is dependent upon the polysaccharide composition of pentoses and uronic acid. The obtained concentrations of furfural (13 and 14 mmol/L), D-xylose (6.2 and 10 mmol/L), and L-arabinose (2.5 and 2.7 mmol/L) remained the same when the galacturonic acid was fed either as a polymer or a monomer under the same reaction conditions (0.01 M SA, 90 min and 433 K). OPW is proposed as a feedstock in a biorefinery, in which on a per kg OPW dry basis, 90 g of pectin and 15 g of furfural were produced in the most favorable case. We conclude that the co-production of pectin and furfural from OPW is economically feasible.
ABSTRACT
The aim of this study was to characterize the morphological properties of amorphous silica nanoparticles (SiO2 NPs), their cytotoxicity and intracellular location within Human Osteoblasts (HOB). Additionally, SiO2 NPs were explored for their effectivity as carriers of CRTC3-siRNA on Human Preadipocytes (HPAd), and thus downregulate RGS2 gene expression. SiO2 NPs were synthesized using the method of Stöber at 45 °C, 56 °C, and 62 °C. These were characterized via TEM with EDS, Zeta Potential and FT-IR. Cytotoxicity was evaluated by XTT at three concentrations 50, 100 and 500 µg/mL; SiO2 NPs intracellular localization was observed through Confocal Laser Scanning Microscope. Delivering siRNA effectivity was measured by RT-qPCR. Morphology of SiO2 NPs was spherical with a range size from 64 to 119 nm; their surface charge was negative. Confocal images demonstrated that SiO2 NPs were located within cellular cytoplasm. At a SiO2 NPs concentration of 500 µg/mL HOB viability decreased, while at 50 µg/mL and 100 µg/mL cell viability was not affected regardless SiO2 NPs size. SiO2 NPs-CRTC3-siRNA are effective to down-regulate RGS2 gene expression in HPAd without cytotoxic effects. The developed SiO2 NPs-CRTC3-siRNA are a promising tool as a delivery vehicle to control obesity.
