With the advent of recombinant DNA technology, recombinant protein expression has become an important tool in the study of the structure, function and identification of new proteins, especially those with therapeutic functions. Escherichia coli has been the predominant prokaryote used in genetic engineering studies due to the abundance of information about its metabolism. Despite significant advances in molecular biology and immunology of infections, there are as yet no prophylactic drugs capable of preventing visceral leishmaniasis. It is therefore important to identify specific antigens in order to develop vaccines and diagnostic kits against this disease. The objective of this study was to evaluate the influence of culture medium on the production of eIF antigen from Leishmania chagasi in recombinant Escherichia coli. An induction procedure using IPTG was carried out in a series of trials, to observe the influence of culture medium (2xTY, TB) under expression of the recombinant eIF protein. Results showed that recombinant protein expression was associated to growth and that the highest eIF antigen expression was obtained in the 2xTY medium.

Visceral leishmaniasis is a potentially fatal disease caused by Leishmania infantum chagasi in the New World. Anti-leishmanial treatment is problematic because antileishmanial drugs are toxic and costly and drug resistance is emerging. Moreover, there is no effective and safe vaccine approved for human use against any form of leishmaniasis. It seems likely that both a subunit vaccine and an optimized diagnostic test would benefit from the production of recombinant antigens. However, for recombinant protein production, the composition of the cell growth medium must be carefully formulated and monitored, because it may have significant metabolic effects on both the cells and protein expression. Thus, the aim of this study was to optimize the culture medium for cell growth and the expression of the 648 antigen from Leishmania i. chagasi in recombinant Escherichia coli M15. The induction allowed the expression of the 648 antigen; this was confirmed by electrophoresis, which showed a protein with a molecular mass of 24 kDa. The results showed that the higher cell concentration obtained in TB medium can be explained by the larger number of components such as amino acids and vitamin precursors contained in this complex medium, as well as glycerol as a carbon and energy source. Acetic acid excretion, detected at the end of fermentation, resulted in an inhibitory effect for both cell growth and protein production, because this was above the concentration limit of 0.9 g L −1 .

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O reaproveitamento do caroço de açaí tem ganhado destaque por ser uma alternativa para redução do impacto ambiental, bem como para o proveito econômico, visando a agregação de valor ao resíduo.  No presente trabalho, realizou-se a preparação dos caroços de açaí, onde consistiu nos processos de higienização, secagem, remoção do tecido fibroso, tratamento térmico, torrefação artesanal, moagem e peneiramento. As caracterizações físico-químicas iniciaram com a extração de lipídeos pelo método Soxhlet e o teor de proteínas totais pelo método Kjealdahl. Já a análise de polifenóis totais e taninos foram realizadas com base no preparo do extrato aquoso, sendo quantificados pela leitura em espectrofotômetro com curva de calibração com um padrão de referência, além da aplicação de análise sensorial com entrevistados. Os resultados obtidos em comparação aos caroços in natura da literatura mostraram diferenças que são justificadas pelos processos de preparação aplicados inicialmente. O aproveitamento deste resíduo, além de benefícios econômicos, permite um desenvolvimento regional mais sustentável.