Heterologous expression of xylanase and α-amilase genes in lactic acid bacteria

MORTERA PABLO; TADDIA ANTONELA; ALARCÓN SERGIO; TUBIO GISELA; MAGNI CHRISTIAN

Mar del Plata

Congreso; LI Reunión SAIB 2015; 2015

The enzymes of the glycoside hydrolase family are used industrially as dietary additive in animal feed. This innovative practice helps improve weight gain of the animals when they are fed mainly with fibrous nutritious low quality forages. In dietary supplements, the additions of enzymes (cellulase, xylanase or amylase) in which degrade polysaccharides (cellulose, hemicellulose or starch) to simple sugars, improves digestibility of fiber in foods like corn, barley, soybeans, sorghum or poor pastures, allows the reduction of diarrhea, increased weight of the animals (such as chickens and pigs monogastric or ruminant) and improves overall health thereof. The use of BAL for heterologous expression is interesting since the most of lactic acid bacteria (LAB) species are safe for animal consumption and in many cases beneficial, besides contributing to the biological process of fermentation in silage fodder. In this work, the α-amylase enzyme from Bacillus licheniformis was expressed constitutively both in Escherichia coli as in Enterococcus faecalis, using pGAL9 plasmid. In addition, the xylanase enzyme from B. subtilis was expressed an inducible way both in E. coli (pET28 system) as in Lactococcus lactis (pNZ system). Enzymes were exported using different signal peptides and the corresponding activities were detected in the culture supernatants