Expression of Rumen Microbial Fibrolytic Enzyme Genes in Probiotic Lactobacillus reuteri

Abstract

ABSTRACT This study was aimed at evaluating the cloning and expression of three rumen microbial fibrolytic enzyme genes in a strain of Lactobacillus reuteri and investigating the probiotic characteristics of these genetically modified lactobacilli. The Neocallimastix patriciarum xylanase gene xynCDBFV , the Fibrobacter succinogenes β-glucanase (1,3-1,4-β- d -glucan 4-glucanohydrolase [EC 3.2.1.73]) gene, and the Piromyces rhizinflata cellulase gene eglA were cloned in a strain of L. reuteri isolated from the gastrointestinal tract of broilers. The enzymes were expressed and secreted under the control of the Lactococcus lactis lacA promoter and its secretion signal. The L. reuteri transformed strains not only acquired the capacity to break down soluble carboxymethyl cellulose, β-glucan, or xylan but also showed high adhesion efficiency to mucin and mucus and resistance to bile salt and acid.