ORIGINAL PAPER In vitro fermentation of prebiotics by Lactobacillus plantarum CFR 2194: selectivity, viability and effect of metabolites on b-glucuronidase activity Madhu Arenahalli Ningegowda • Prapulla Siddalingaiya Gurudutt Received: 15 November 2010 / Accepted: 9 September 2011 / Published online: 23 September 2011 Ó Springer Science+Business Media B.V. 2011 Abstract Prebiotic Fructooligosaccharides (FOS) escape metabolism in upper GI tract undergo microbial metabolism in colon and thereby influence the nature, type and number of intestinal microbiota to improve host’s health. The present study focuses on the ability of Lactobacillus plantarum CFR 2194 to utilize FOS as a selective carbon and energy source. The effect of fermentative metabolites of L. plantarum on the b-glucuronidase was also investigated. A total of 16 strains of lactobacilli were assessed for their ability to ferment oli- gosaccharides. L. plantarum CFR 2194, an isolate from kanjika was found to utilize FOS effectively. Lactic acid was the main metabolic end product, followed by acetic acid, butyric acid, formic acid and ethanol. The inhibitory effects of these metabolites have been confirmed through the reduction of b-glucuronidase activity. L. plantarum when co-cultured with b-glucuronidase producing E. coli, in a basal media containing FOS as an energy source, could inhibit the growth of the pathogen during the course of fer- mentation. The results showed that L. plantarum CFR 2194 has the ability to utilize the prebiotic FOS as a selective carbon and energy source. The organism could inhibit the growth of the pathogen which produces b-glucuronidase and lowered its activity by the metabolites of FOS which indi- cates the probable use of L. plantarum through dietary intervention in combating colon carcinogenesis. Keywords Lactobacillus plantarum  Synbiotics  b-Glucuronidase  Short chain fatty acids  Oligosaccharides Introduction The ability of certain bacteria to ferment oligosaccharides selectively is an important probiotic characteristic (Kaplan and Hutkins 2000). Prebiotic oligosaccharides are fer- mented only by specific strains of bifidobacteria and lac- tobacilli, thus use of prebiotic enriched diet might lead to selective enhancement of beneficial microbes in the colon. A dietary prebiotic is defined as ‘‘a selectively fermented ingredient that results in specific changes in the composi- tion and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health’’ (Gibson et al. 2010). Many studies have now suggested that prebiotics are a valid approach to the dietary manipulation of the colonic microflora (Kleessen et al. 2001). In addition to the desir- able effect of increased bifidobacteria and lactobacilli, short-chain fatty acids (SCFAs) are produced as the end products of oligosaccharide fermentation. SCFAs are absorbed by the perfused human colon in a concentration dependent manner and are the major respiratory fuels for colonocytes, supplying up to 60–70% of their energy needs (Ruppin et al. 1980; Livesey and Elia 1995). SCFAs also stimulate the growth of colorectal mucosal cells, retard mucosal atrophy, and decrease the risk of malignant transformation in the colon. Among various SCFAs, the butyrate has been shown to be particularly effective in decreasing the risk of malignant transformation in the colon (Mentschel and Claus 2003). One specific group of oligosaccharides that has attracted much commercial interest as prebiotics is the FOS. These compounds are present in variety of edible plants including banana, barley etc. and also in honey. They can be obtained either by the hydrolysis of inulin, a natural source or transfructosylation of sucrose (Sangeetha et al. 2005). Their general structure can be represented by GF n or F n , in M. Arenahalli Ningegowda  P. Siddalingaiya Gurudutt (&) Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute, Mysore 570 020, India e-mail: prapullasg@yahoo.co.in 123 World J Microbiol Biotechnol (2012) 28:901–908 DOI 10.1007/s11274-011-0887-z