Estudo da produção e purificação parcial de enterocina utilizando Enterococcus spp. / Study of enterocin production and partial purification by Enterococcus spp.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Bacteriocins are protein substances produced by bacteria that are bactericidal or bacteriostatic against sensitive bacterial species. Both gram-negative and gram-positive organisms, including the lactic acid bacteria, produce these compounds. These bacteria are extensively used in food processing, for their contribution to shelf life, texture and organoleptic properties. Some strains of entecococci can produce bacteriocins active against pathogenic bacteria such as Listeria monocytogenes. Bacteriocins produced by Enterococcus faecium and Enterococcus faecalis are small, hydrophobic and termostable peptides. The aim of this work was the study of enterocin production by E. faecium and E. faecalis. Initially, fermentations assays were carried out in Erlenmeyers flasks for determining the best conditions of carbon sources (glucose, sucrose and brown sugar), pHinitial (4,0; 6,0; 8,0 or 10,0) and agitation (0 or 200rpm). The modified basal medium without glucose was used as base medium and the different carbon employed. The flasks incubated at 37°C for 24h. In a second stage, the experiments were carried out in laboratory scale fermentor for 24h. During the fermentations samples were collected at intervals of 24 h or 1h, for determination of enterocin activity, biomass (cell dry mass), pH and sugar contents. The first phase in Erlenmeyers flasks indicated that using E. faecium for enterocin production the best culture conditions were pHinitial 10,0, sucrose and without agitation. The maximum enterocin production was 2,81UE. The results indicated that the best conditions for enterocin production using E. faecalis were pHinitial 10,0, 200rpm and brown sugar, with enterocin activity of 1,68UE. In fermentor the highest enterocin activity was 2,94UE after 21h of fermentation in experiment using pHinitial 10,0, 200rpm, sucrose and E. faecium. The enterocin activity was 1,30UE after 12h of incubation in experiment with pHinitial 10,0, 200rpm, brown sugar and E. faecalis. When it was used L. monocytogenes Scott A as microorganism test occurred its inhibition by enterocin of E. faecium and E. faecalis.

ASSUNTO(S)

bacteriocin enterococcus proteinas de bacterias enterocin agentes antibacterianos

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