Optimization of Lipase-Catalyzed Transesterification of Cotton Seed Oil for Biodiesel Production Using Response Surface Methodology

The aim of this work was to study the biodiesel production from cotton seed oil by lipase produced by Pichia guilliermondii lipase, which was immobilized onto hydrophobic magnetic particles (HMPs). The optimum reaction conditions were determined for lipase dosage, methanol-to-oil molar ratio, temperature and water content. Using response surface methodology, a quadratic polynomial equation was obtained for fatty acid methyl esters (FAMEs) content by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. The optimal conditions for the enzymatic transesterification were temperature of 38.76℃, 31.3% immobilized lipase, 10.4% water content, and a methanol-to-oil molar ratio of 4.715:1. The gas chromatography- mass spectrometry showed that biodiesel was mainly composed of the methyl esters of hexadecanoic, 9,12-octadecadienoic and 9-octadecadienoic acid.

A new biosurfactant produced by Candida glabrata UCP 1002: characteristics of stability and application in oil recovery

The production of a new biosurfactant by Candida glabrata UCP1002 was studied to evaluate the influence of the concentration of the cotton seed oil, glucose and yeast extract. The dynamics of the growth and surfactant production were showed for all the cultivation conditions studied. The best emulsification of the n-hexadecane, quantified by the emulsifying index was observed in the medium containing 7.5 percent cotton seed oil, 5 percent glucose and 0.3 percent yeast extract. The isolated biosurfactant showed a CMC of 2.5 percent and the surface tension at that point showed to be 31mN/m. The potential application of the biosurfactant in oil recovery from the sand, in acid and alkaline environments and over exposure to high salinity and different temperatures was demonstrated by the percentage of oil removal and by the stability of the surface tension, respectively.

A produção de um novo biossurfactante por Candida glabrata UCP1002 foi inicialmente investigada com a finalidade de avaliar a influência da concentração dos substratos óleo de algodão, glicose e extrato de levedura. As cinéticas de crescimento e de produção do surfactante foram demonstradas para todas as condições de cultivo testadas. A melhor emulsificação do nhexadecano, quantificada através do índice de emulsificação foi observada na condição de cultivo contendo 7,5 por cento de óleo de algodão, 5 por cento de glicose e 0,3 por cento de extrato de levedura. O biossurfactante produzido apresentou uma concentração micelar crítica de 2,5 por cento, sendo a tensão superficial nesse ponto de 31mN/m. O potencial de aplicação do biossurfactante na recuperação de óleo de areia contaminada, em condições ácidas e alcalinas, bem como sob exposição a altas salinidades e diferentes temperaturas, foram demonstrados com base no percentual de remoção do óleo e na estabilidade da tensão superficial, respectivamente.