Showing papers by "Leonie Asfora Sarubbo published in 2007"

Co-Utilization of Canola Oil and Glucose on the Production of a Surfactant by Candida lipolytica

Abstract: Candida lipolytica synthesized a surfactant in a cultivation medium supplemented with canola oil and glucose as carbon sources. Measurements of biosurfactant production and surface tension indicated that the biosurfactant was produced at 48 h of fermentation. The surface-active species is constituted by the protein–lipid–polysaccharide complex in nature. The cell-free broth was particularly influenced by the addition of salt, the pH and temperature depending on the emulsified substrate (hexadecane or a vegetable oil). After comparison between ethyl acetate and mixtures of chloroform and methanol as solvent systems for surfactant recovery, it was found that ethyl acetate was able to extract crude surfactant material with high product recovery (8.0 g/L). The isolated biosurfactant decreased the surface tension to values of 30 mN/m at the critical micelle concentration. Emulsification properties of the biosurfactant produced were compared to those of commercial emulsifiers and other microbial surfactants.

Enhancement of stability of biosurfactant produced by Candida lipolytica using industrial residue as substrate

Abstract: This work describes experimental results carried out on the fermentation of Candida lipolytica, which produced a new biosurfactant when grown on a vegetable oil refinery residue as substrate. The cell-free culture broth containing the biosurfactant formed stable emulsions with hydrophobic natural compounds. Emulsification properties of the biosurfactant were not affected by salinity; however, treatment at a higher temperature decreased the emulsification activity, indicating applications in oil recovery. The isolated biosurfactant corresponds to a yield of 4.5 g/l, and the surface tension of water was reduced from 71 to 32 mN/m. Preliminary chemical characterizations showed that the biosurfactant consisted of protein (50%), lipid (20%), and carbohydrate (8%).

A goma do cajueiro (Anacardium occidentale L.) como sistema inovador de extração líquido-líquido

Abstract: The exudate gum from Anacardium occidentale L. is a branched acidic heteropolysaccharide easily found in Brazil. Given the importance of cashew tree culture to some regions of Brazil, especially the Brazilian north-western, the knowledge of the characteristics of the gum and the results of researches developed to study its biotechnological application have awaken great scientific and industrial interests. In this work, we describe the literature regarding the polysaccharide and its utilization as an alternative to the conventional processes used in the biopurification of economically high-valued compounds.