Optimization of synthesis of fatty acid methyl esters catalyzed by lipase B from Candida antarctica immobilized on hydrophobic supports

In this work two immobilized preparations of lipase (EC 3.1.1.3) B from Candida antarctica (CALB) were compared for the synthesis of fatty acid methyl esters (FAME) using soybean oil. Commercial Novozym 435 (CALB-435) and CALB immobilized on styrene-divinylbenzene beads (CALB–MCI) were tested for the transesterification reactions. Central composite design (CCD) and response surface methodology (RSM) were used to optimize the reaction parameters, substrate molar ratio, enzyme content, and the added amount of water, on the initial reaction rate as response. The biocatalysts showed different optimal conditions for the production of FAME. For CALB-435, optima conditions were 5.6:1 molar ratio methanol:oil, 25% enzyme, and 5.44% of added water, while for MCI–CALB, these optima were 3:1 molar ratio methanol:oil, 25% enzyme, and 1.18% of added water, resulting in initial reaction rates of 51.47 mmol L−1 h−1, and 57 mmol L−1 h−1 of FAME, respectively. Conversions of 93.38% using CALB-435, and 99.03% using CALB–MCI were obtained after 72 h of reaction under the optimized conditions. Repeated batches of reaction were carried out to test the operational stability of biocatalysts, with both preparations keeping around 70% of their initial activity after eight batches.This work was supported by grants from Brazilian Coordenação de Aperfoiçoamento de Pessoal de Nível Superior (CAPES) and CTQ2009-07568 from Spanish Ministerio de Ciencia e Innovación.Peer Reviewe

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

Clinical, epidemiological and mycological report on 65 patients from the Eastern Amazon region with chromoblastomycosis Relato clínico, epidemiológico e micológico de 65 pacientes com cromoblastomicose procedentes da Amazônia oriental

BACKGROUND: Chromoblastomycosis is a chronic fungal infection caused by fungi from the Dematiaceae family. According to several studies, Fonsecaea pedrosoi is the most common of these fungi. The infection is more common in tropical countries, with the Brazilian state of Pará having one of the largest infected populations worldwide. The disease is difficult to treat and recurrences are common. OBJECTIVES: To describe the epidemiological and mycological aspects of cases of chromoblastomycosis and its clinical forms in the state of Pará, Brazil. METHODS: Mycological exams (direct mycological examinations, culture and microculture) were performed and a clinical/epidemiological evaluation was made of 65 patients receiving care at the Dermatology Department of the Federal University of Pará between 2000 and 2007. The clinical classification proposed by Carrión in 1950 was used in this study. RESULTS: The majority of the patients were male (93.8%), agricultural workers (89.2%) of 45 to 55 years of age, and the majority of lesions (55.4%) were of the verrucous type, located principally on the lower limbs (81.5%). In the majority of the cases investigated (61.5%), the infection had been present for a long time, with a mean duration of 11 years. Direct mycological examination was performed in 86.2% of the patients (n=56). Of these, 96.4% (n=54) tested positive. Culture and microculture were performed in vitro in 47 cases of those that tested positive at direct microscopy, results showing Fonsecaea pedrosoi to be the only agent present in this sample. CONCLUSION: This study highlighted the extent to which chromoblastomycosis still affects the quality of life of the local population, principally individuals working in agriculture. This is a chronic disease for which there is no effective treatment. The importance of continuing to investigate this disease should be emphasized, as further studies may lead to new clinical or epidemiological findings.<br>FUNDAMENTOS: A cromoblastomicose é uma infecção fúngica crônica, causada por fungos da família Dematiaceae, sendo Fonsecaea pedrosoi a mais comum, segundo vários estudos. É mais frequente em países tropicais e o estado do Pará possui grande casuística mundial. A doença é de difícil tratamento e apresenta recorrência frequente. OBJETIVOS: Descrever os aspectos epidemiológicos, micológicos e formas clínicas dos casos de cromoblastomicose procedentes do estado do Pará - Brasil. MÉTODOS: Foram realizados exames micológicos (direto, cultura e microcultivo) e observação clinicoepidemiológica em 65 pacientes do Serviço de Dermatologia da Universidade Federal do Pará, atendidos no período de 2000 a 2007. Empregou-se a classificação clínica proposta por Carrión em 1950. RESULTADOS: Os pacientes eram, em sua maioria, homens (93,8%), lavradores (89,2%), faixa etária entre 45-55 anos, com predominância de lesões verruciformes (55,4%), localizadas principalmente nos membros inferiores (81,5%). A maioria dos casos pesquisados (61,5%) apresentou um longo tempo de doença, com uma média de 11 anos. O exame micológico direto foi realizado em 86,2% (n=56) dos pacientes; destes, 96,4% (n=54) apresentaram resultado positivo. Foram realizados cultura e microcultivo in vitro de 47 pacientes com exame micológico positivo e os resultados mostraram o Fonsecaea pedrosoi como único agente etiológico identificado nesta amostra. CONCLUSÃO: Este estudo mostrou o quanto a cromoblastomicose ainda compromete a qualidade de vida da população local, principalmente a de indivíduos que trabalham em lavouras, cursando com evolução crônica e sem tratamento eficaz. Observa-se a importância de dar continuidade a este estudo, o que poderá proporcionar novas contribuições clínicas ou epidemiológicas