Microbial production of levanase for specific hydrolysis of levan.

A newly isolated bacterial strain from Tunisian thermal source was selected for its ability to produce extracellular levanase when grown on levan substrate. The optimization of carbon source, nitrogen source, temperature and initial pH of the growth medium in submerged liquid cultures were investigated. In fact, levan was found to be a good inducer of levanase enzymes.

Antioxidant and antimicrobial activities of Lycium shawii fruits extract.

Crude extracts from the fruit of Lycium shawii, a plant collected from the south of Tunisia, were screened for their in vitro antioxidant, antimicrobial and antifungal activities. The dried fruits were extracted with EtOH and an aqueous suspension of the obtained EtOH extract was partitioned successively with CHCl3, CH2Cl2, EtOAc and n-BuOH, leaving residual water extract. Total phenolic content of extracts from these fruits were also determined.

Structural determination and NMR characterization of a bacterial exopolysaccharide.

A strain of Bacillus licheniformis with high exopolysaccharide (EPS) production ability was isolated and identified. A new type of EPS was isolated from the strain fermentation and its structural characteristics were investigated and elucidated by partial and total acid hydrolysis, Fourier transform infrared, and (1)H and (13)C NMR spectroscopy including 2D (1)H, COSY, NOESY, XHCOR and HMBC experiments. Based on obtained data, the EPS was found to be a levan composed of linear chains of (2→6)-linked β-d-fructofuranosyl residues with connections β (2→6).

Antioxidant effect of nondigestible levan and its impact on cardiovascular disease and atherosclerosis.

Levan polysaccharide, a type of fructan, has been shown to favorably affect diabetes type 2 and hypercholesterolemia. Recent reports have indicated that excessive oxidative stress contributes to the development of atherosclerosis linked metabolic syndrome. The objective of this current study was to investigate the possible protection against oxidative stress linked atherosclerosis.

Partial purification of a Bacillus licheniformis levansucrase producing levan with antitumor activity.

The extracellular fructosyltransferase (FTase) of a novel strain of Bacillus licheniformis capable of producing fructooligosaccharides (FOS) and a polysaccharide type levan was obtained and partially purified. The purification was achieved by ammonium sulfate precipitation, DEAE cellulose and gel filtration chromatographies. The enzyme was partially purified as determined by SDS-PAGE, and the specific activity reached was 67.

Hypolipidemic effect of diet supplementation with bacterial levan in cholesterol-fed rats.

Levan polysaccharide, a type of fructan, has been shown to have industrial applications as a new industrial gum in the fields of cosmetics, foods like dietary fiber and pharmaceutical goods. The objective of this current study was to investigate the possible hypolipidemic and antioxidative effects of levan in rats fed with a high-cholesterol diet. Animals were allocated into four groups of six rats each: a normal diet group (Control), normal rats received levan (L), a high-cholesterol diet group (Chol) and a high-cholesterol diet with a daily dose of levan equivalent to 5%.

Microbial production of levansucrase for synthesis of fructooligosaccharides and levan.

A newly isolated thermophilic bacterial strain from Tunisian thermal source was identified as Bacillus sp. and was selected for its ability to produce extracellular levansucrase. Following the optimization of carbon source, nitrogen source, temperature and initial pH of the growth medium in submerged liquid cultures.

Oral administration of levan polysaccharide reduces the alloxan-induced oxidative stress in rats.

This study aimed to evaluate the effect of a polysaccharide named levan, which was produced by new isolated bacteria, on oxidative stress and hyperglycemia in alloxan-induced diabetic rats. Levan polysaccharide was given in drinking water for 60 days at a daily dose equivalent to 2%. The oral administration of levan in diabetic rats caused a decrease in glucose level in plasma and an increase of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities in both pancreas and liver.

Antidiabetic activity of levan polysaccharide in alloxan-induced diabetic rats.

This study aims to examine the effects of polysaccharide levan on oxidative stress and hyperglycemia in alloxan-induced diabetic rats. Levan, used in this study, was a microbial levan synthetisized by a non pathogenic bacteria recently isolated and identified as Bacillus licheniformis. Animals were allocated into four groups of six rats each: a control group (Control), diabetic group (Diab.