Alma Delia Hernández-Fuentes

Extraction and characterization of collagen from rabbit skin: partial characterization

Extraction and characterization of collagen were carried out in rabbit skins as a new alternative for collagen type I. Acetic acid and pepsin were for the extraction of soluble and insoluble collagen, respectively. The enzymatic treatment yielded higher amount of collagen (71%). The average pH value was 6.3, no matter what the method of extraction was. Denaturation temperature of collagen was found at 36°C approximately in two different techniques: Rheometer and Differential Scanning Calorimetry (DSC). Despite the amount of collagen in solution was low, its viscosity was high because of the hydrodynamic behaviour of collagen molecules. Sodium dodecyl sulphate polyacrylamide gel electrophoresis results showed three different bands that reflected two alpha-chains and one beta-chain with molecular weights of 102, 118 and 220 kDa, respectively. Determination of hydroxyproline gave evidence that the extracted material was collagen. It was concluded that rabbit skin could be an alternative source for the extraction of collagen.

Characterization of a yeast culture extract compound stimulating the growth of an anaerobic cellulolytic consortium

In this work the compound obtained from yeast culture extract (YCE) that stimulated the activity of an anaerobic cellulolytic consortium (ACC) was characterized. YCE were obtained at different pH (4, 7 and 10) and ultra-filtered 300 and 30 kDa membranes (UYE). The 30 kDa UYE was heated to 60 °C, 90 °C and 120 °C and gel filtered (GYF). Mid infrared spectroscopy, protein and carbohydrate analysis of GYF were conducted. Results showed that YCE, UYE and GYF significantly stimulated (p < 0.05) the biomass production, acetate concentration and carboxymethyl cellulase activity of the ACC, in relation to the control. The GYF had an estimated molecular mass of 4 kDa. Mid-infrared and biochemical analysis of GYF suggested that the active compound is a peptide.