title: Exopolysaccharides from yeast: insight into optimal conditions for biosynthesis, chemical composition and functional properties - review.
abstract: BACKGROUND
  xopolysaccharides (EPS) are not a well-established group of metabolites. An industrial scale    of this EPS production is limited mainly by low yield biosynthesis. Until now, enzymes and biosynthesis pathways, as well as the role of regulatory genes, have not been described. Some of yeast EPS show antitumor, immunostimulatory and antioxidant activity. Others, absorb heavy metals and can function as bioactive components of food. Also, the potential of yeast EPS as thickeners or stabilizers can be found. Optimal conditions for the biosynthesis of yeast exopolysaccharides require strong oxygenation and low temperature of the culture, due to the physiology of the producer strains. The medium should contain sucrose as a carbon source and ammonium sulfate as inorganic nitrogen source, wherein the C:N ratio in the substrate should be 15:1. The cultures are long and the largest accumulation of polymers is observed after 4 or 5 days of culturing. The structure of yeast EPS is complex which affects the strain and culture condition. The EPS from yeast are linear mannans, pullulan, glucooligosaccharides, galactooligosaccharides and other heteropolysaccharides containing α-1,2; α-1,3; α-1,6; β-1,3; β-1,4 bonds. Mannose and glucose have the largest participation of carbohydrates for.
  
  
  METHODS
  t exopolysaccharides (EPS) are not a well-established group of metabolites. An industrial scale    of this EPS production is limited mainly by low yield biosynthesis. Until now, enzymes and biosynthesis pathways, as well as the role of regulatory genes, have not been described. Some of yeast EPS show antitumor, immunostimulatory and antioxidant activity. Others, absorb heavy metals and can function as bioactive components of food. Also, the potential of yeast EPS as thickeners or stabilizers can be found. Optimal conditions for the biosynthesis of yeast exopolysaccharides require strong oxygenation and low temperature of the culture, due to the physiology of the producer strains. The medium should contain sucrose as a carbon source and ammonium sulfate as inorganic nitrogen source, wherein the C:N ratio in the substrate should be 15:1. The cultures are long and the largest accumulation of polymers is observed after 4 or 5 days of culturing. The structure of yeast EPS is complex which affects the strain and culture condition. The EPS from yeast are linear mannans, pullulan, glucooligosaccharides, galactooligosaccharides and other heteropolysaccharides containing α-1,2; α-1,3; α-1,6; β-1,3; β-1,4 bonds. Mannose and glucose have the largest participation of carbohydrates formin.
  
  
  RESULTS
  t exopolysaccharides (EPS) are not a well-established group of metabolites. An industrial scale    of this EPS production is limited mainly by low yield biosynthesis. Until now, enzymes and biosynthesis pathways, as well as the role of regulatory genes, have not been described. Some of yeast EPS show antitumor, immunostimulatory and antioxidant activity. Others, absorb heavy metals and can function as bioactive components of food. Also, the potential of yeast EPS as thickeners or stabilizers can be found. Optimal conditions for the biosynthesis of yeast exopolysaccharides require strong oxygenation and low temperature of the culture, due to the physiology of the producer strains. The medium should contain sucrose as a carbon source and ammonium sulfate as inorganic nitrogen source, wherein the C:N ratio in the substrate should be 15:1. The cultures are long and the largest accumulation of polymers is observed after 4 or 5 days of culturing. The structure of yeast EPS is complex which affects the strain and culture condition. The EPS from yeast are linear mannans, pullulan, glucooligosaccharides, galactooligosaccharides and other heteropolysaccharides containing α-1,2; α-1,3; α-1,6; β-1,3; β-1,4 bonds. Mannose and glucose have the largest participation of carbohydrates forming EPS.
authors.affiliation: Department of Biotechnology, Microbiology and Food Evaluation, Warsaw University of Life Sciences - SGGW, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Gientka
authors.affiliation: Department of Biotechnology, Microbiology and Food Evaluation, Warsaw University of Life Sciences - SGGW, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Błażejak
authors.affiliation: Department of Biotechnology, Microbiology and Food Evaluation, Warsaw University of Life Sciences - SGGW, Poland.
authors.forename: Lidia
authors.initials: L
authors.lastname: Stasiak-Różańska
authors.affiliation: Department of Biotechnology, Microbiology and Food Evaluation, Warsaw University of Life Sciences - SGGW, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Chlebowska-Śmigiel
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use; D019149:Bioreactors / Q000382:microbiology*; D002240:Carbohydrate Sequence; D002614:Chelating Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use; D003080:Cold Temperature; D005503:Food Additives / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D062610:Fungal Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry / Q000627:therapeutic use; D010084:Oxidation-Reduction; D015003:Yeasts / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D000276:Adjuvants, Immunologic; D000970:Antineoplastic Agents; D000975:Antioxidants; D002614:Chelating Agents; D005503:Food Additives; D062610:Fungal Polysaccharides
keywords: EPS; exopolysaccharides; yeast