title: Characterization and biocompatibility of glucan: a safe food additive from probiotic Lactobacillus plantarum DM5.
abstract: BACKGROUND
  Exopolysaccharide produced by lactic acid bacteria are the subject of an increasing number of studies for their potential applications in the food industry as stabilizing, bio-thickening and immunostimulating agents. In this regard, the authors isolated an exopolysaccharide producing probiotic lactic acid bacterium from fermented beverage Marcha of north eastern Himalayas.
  
  
  RESULTS
  The isolate Lactobacillus plantarum DM5 showed extracellular glucansucrase activity of 0.48 U mg⁻¹ by synthesizing natural exopolysaccharide glucan (1.87 mg mL⁻¹) from sucrose. Zymogram analysis of purified enzyme confirms the presence of glucosyltransferase of approximately 148 kDa with optimal activity of 18.7 U mg⁻¹ at 30 °C and pH 5.4. The exopolysaccharide was purified by gel permeation chromatography and had an average molecular weight of 1.11 × 10⁶ Da. Acid hydrolysis and structural characterization of exopolysaccharide revealed that it was composed of d-glucose residues, containing 86.5% of α-(1→6) and 13.5% of α-(1→3) linkages. Rheological study exhibited a shear thinning effect of glucan appropriate for food additives. A cytotoxicity test of glucan on human embryonic kidney 293 (HEK 293) and human cervical cancer (HeLa) cell lines revealed its nontoxic biocompatible nature.
  
  
  CONCLUSIONS
  This is the first report on the structure and biocompatibility of homopolysaccharide α-D-glucan (dextran) from probiotic Lactobacillus plantarum strain and its unique physical and rheological properties that facilitate its application in the food industry as viscosifying and gelling agent.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, India.
authors.forename: Deeplina
authors.initials: D
authors.lastname: Das
authors.forename: Arun
authors.initials: A
authors.lastname: Goyal
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D001628:Beverages / Q000382:microbiology; D002240:Carbohydrate Sequence; D055598:Chemical Phenomena; D004032:Diet / Q000208:ethnology; D005285:Fermentation; D005503:Food Additives / Q000009:adverse effects / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D005936:Glucans / Q000009:adverse effects / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D016695:Glycosyltransferases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007194:India; D048191:Lactiplantibacillus plantarum / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D055595:Mechanical Phenomena; D008970:Molecular Weight; D019936:Probiotics / Q000009:adverse effects / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature; D018675:Toxicity Tests
chemical_list: D001426:Bacterial Proteins; D005503:Food Additives; D005936:Glucans; D016695:Glycosyltransferases; C033837:alternansucrase
keywords: Lactobacillus plantarum; Marcha; glucan; glucansucrase; probiotic