Diana Marcela Escobar Sierra

Comparison of extraction methods of chitin from ganoderma lucidum mushroom obtained in submerged culture

The chitin was isolated from the Ganoderma lucidum submerged cultures mycelium as potential source of chitin under biotechnological processes. The extraction of chitin was carried out through 5 different assays which involved mainly three phases: pulverization of the mushroom, deproteinization of the mycelia with NaOH solution, and a process of decolorization with potassium permanganate and oxalic acid. The chitin contents extracted from 9-day mycelia were 413, 339, 87, 78, and 144 mg/g−1 (milligrams of chitin/grams of dry biomass) for A1, A2, A3, A4, and A5, respectively. Obtained chitin was characterized by X-Ray Diffraction (XRD), by Fourier transform infrared spectroscopy (FTIR), and by thermal analysis (TGA). The results showed that Ganoderma lucidum chitin has similar characteristic of chitin from different fonts. The advantage of the biotechnological processes and the fact that Ganoderma lucidum fungus may be used as a potential raw material for chitin production were demonstrated.

Optimización de un protocolo de extracción de quitina y quitosano desde caparazones de crustáceos.

En este trabajo se extrajeron quitina y quitosano de caparazones de crustaceos, principalmente de cangrejos, langostas y mejillones, variando algunos parametros respecto a los protocolos reportados en la literatura. El procedimiento propuesto para la extraccion desde los caparazones de crustaceos involucro procesos de desmineralizacion, desproteinizacion y desacetilacion a las cuales se les ha adicionado una etapa de purificacion. Los polimeros obtenidos fueron caracterizados por Microscopia Optica (MO), Difraccion de Rayos X (DRX), Espectroscopia de Infrarrojo con Transformada de Fourier (FTIR) y Analisis Termo Gravimetrico (TGA). Los productos obtenidos mostraron caracteristicas comparables con los biopolimeros reportados en la literatura

Suspension Rheology, Porosity and Mechanical Strength of Porous Hydroxyapatite Obtained by Gel-casting and Infiltration

The gel-casting technique (GC) and infiltration of polymer foam combined with gel-casting (IG) were used to produce hydroxyapatite porous bodies. Due to the fact that the process begins with the preparation of the suspensions, it is necessary to know the rheological properties of the ceramic slurry. This is a critical factor needed to optimize the mechanical strength of the porous body obtained. Therefore, the rheological behavior of various HA slurries was assessed. 40 and 50% solids and three different monomers were evaluated. Subsequently, the compressive strength and porosity of the porous bodies obtained were evaluated. The results revealed that the chemical composition of each monomer can affect the dispersion and rheological properties of the suspension, which directly affects the mechanical properties of the porous bodies. The porous bodies obtained by the GC technique showed strengths higher than those obtained by IG compression. The control executed over the rheology of the suspension was more effective in bodies produced by GC, because IG pyrolysis of polyurethane foam also influenced the mechanical properties of the final product.

Influence of the type of manufacturing technique on the porosity and interconnectivity of hydroxyapatite scaffolds

Tissue engineering for bone regeneration requires the use of platforms called scaffolds that serve as a support for the invasion of new cells in which a possible exchange of fluids and nutrients can occur. To this end, the scaffolds must have characteristics such as an adequate pore size, porosity. The aim of this research was to produce hydroxyapatite scaffolds using the gel-casting technique and the gel-casting technique combined with the infiltration of polymer foams to determine how these manufacturing methods influence the pore size, percentage of porosity and interconnectivity. The influence of the percentage of solids and monomer type on the aforementioned characteristics was also evaluated. It was found that such characteristics depend on factors that are inherent to the technique used. Thus, for the gel-casting technique the viscosity of the slurry, the amount and stability of the foam produced and the percentage of solids were the influential factors. However, for the gel-casting combined with the nfiltration of foam technique, the determining factor was the type of polymer foam used as a template.