Optimization of ethyl ester production from olive and palm oils using mixtures of immobilized lipases

Although reactions of transesterification are generally catalyzed by one specific lipase preparation, the concept of “combi-lipase” could be better explored for the production of biodiesel, since oils are heterogeneous substrates. In this research, we tested this concept by evaluating the enzymatic transesterification of olive and palm oils, two diverse fatty acid compositions, using standalone or mixtures of three immobilized lipases as biocatalysts: Novozym 435 (CALB), Lipozyme TL-IM (TLL), and Lipozyme RM-IM (RML). For olive oil, the combination of 29.0% of TLL, 12.5% of RML, and 58.5% of CALB was the best, allowing for 95% conversion efficiency in 18 h of reaction, up from 50% for the best individual lipase (CALB). For palm oil, the best enzyme combination was 52.5% of TLL and 47.5% of RML, resulting in 80% of conversion of ethyl esters in 18 h, compared to only 44% when standalone TLL was used. Repeated batches of reaction were carried out in order to test the operational stability of the combi-lipase systems, with results showing that they could be used for at least seven cycles keeping higher than 80% of their initial activities.This work was supported by grants from Brazilian Coordenação de Aperfoiçoamento de Pessoal de Nível Superior (CAPES) and CTQ2013-41507-R from Spanish MINECO.Peer Reviewe

Distribuição espacial de Mesadenella cuspidata (Lindl.) Garay (Orchidaceae) em uma floresta ribeirinha em Santa Maria, RS, Brasil Spatial distribution of Mesadenella cuspidata (Lindl.) Garay (Orchidaceae) in a riparian forest, Santa Maria, RS, Brazil

Mesadenella cuspidata é uma orquídea terrícola encontrada no interior de florestas no Sul do Brasil. Apesar de seu valor ecológico e ornamental, pouco se conhece sobre a biologia desta espécie. Os objetivos deste trabalho foram identificar o padrão de distribuição espacial de M. cuspidata e verificar se há correlação entre o número de indivíduos jovens e adultos em uma floresta ribeirinha. Para o levantamento, foram amostradas 60 parcelas de 16m² cada. Durante agosto e setembro/2001 foram inventariados os indivíduos jovens e adultos das parcelas. Para identificar-se o padrão de distribuição espacial, utilizaram-se o índice de Morisita (MI) e a razão de variância/média (R). Foram encontrados 463 indivíduos jovens e 178 adultos. Indivíduos jovens e adultos apresentaram distribuição espacial agrupada, sendo que os adultos (IM = 2,17; R = 4,52) estão mais agrupados que os jovens (IM = 1,82; R = 7,82). O coeficiente de correlação linear encontrado r = 0,61, demonstrou que a densidade de indivíduos adultos está altamente relacionada à densidade de indivíduos jovens.<br>Mesadenella cuspidata (Lindl.) Garay is a terrestrial orchid found inside Southern Brazilian forests. In spite of its ecological and ornamental value, little information is aviable on its biology. The aim of this work was the identification of the spatial distribution patterns of M. cuspidata in a riparian forest. We have sampled 60 quadrats of 16m² each. All the young and adult individuals of the quadrats were included. To identify the pattern of spatial distribution, the Morisita Index (MI) and the variance/mean Reason (R) were used. The linear correlation coefficient was used to verify if there is correlation between populations of the juvenils and adults. From 641 individuals sampled, 463 were juvenils and 178 were adults. Juvenils and adult individuals presented gregarious spatial distribution, but the adults (MI = 2,17; R = 4,52) were more gregarious than the juvenils (IM = 1,82; R = 7,82). The high relation between the densities of adults and juvenils had been demonstrated by the value of the linear correlation coefficient found, r = 0,61