The production of fructo oligo sugars (FOS) and fructosyl transferases (FTase) has gained tremendous commercial importance worldwide. It is worthwhile to find out microbes with the ability to synthesize these products for therapeutic purposes. In the present study, 25 strains of lactic acid bacteria (LAB) were isolated from fermented maize product and screened for transfructosylation activity. Among the six positive isolates, LAB16 exhibited the highest enzyme activity (210.89 U.ml-1) and identified as Lactobacillus plantaram. In order to improve the production, different acceptor molecules were tested. Among them, the highest enzyme production (308.02 U.ml-1) was observed with glucose grown cultures followed by sucrose (253.09 U.ml-1). The maximum growth and glycansucrase activity of L. plantaram LAB 16 was attained after 36h of growth, both in glucose and sucrose MRS broth. With varying level of sucrose concentration, the higher one inhibited the microbial activity. The entire protein fraction prepared from the ammonium sulphate method showed FTase activity, but the highest enzyme activity was observed with 50-60 % of ammonium sulphate saturation level. In vitro FTase activity in SDS-PAGE showed two isoforms of Fructosyl transferase (FTase) at 25 KDa and 38 KDa, respectively. Thin layer chromatography analysis of crude enzyme extract of L. plantaram LAB 16 revealed the presence of bioactive oligosugars such as kestose and nystose.
Naganandhini et al. (Sun,) studied this question.