title: Production of extracellular polysaccharides by submerged mycelial culture of Laetiporus sulphureus var. miniatus and their insulinotropic properties.
abstract: In the present study, optimum culture conditions for the production of extracellular polysaccharides (EPS) in submerged culture of an edible mushroom, Laetiporus sulphureus var. miniatus and their stimulatory effects on insulinoma cell (RINm5F) proliferation and insulin secretion were investigated. The maximum mycelial growth (4.1 g l(-1)) and EPS production (0.6 g l(-1)) in submerged flask culture were achieved in a medium containing 30 g l(-1) maltose, 2 g l(-1) soy peptone, and 2 mM MnSO(4).5H2O at an initial pH 2.0 and temperature 25 degrees C. In the stirred-tank fermenter under optimized medium, the concentrations of mycelial biomass and EPS reached a maximum level of 8.1 and 3.9 g l(-1), respectively. Interestingly, supplementation of deep sea water (DSW) into the culture medium significantly increased both mycelial biomass and EPS production by 4- and 6.7-fold at 70% (v/v) DSW medium, respectively. The EPS were proved to be glucose-rich polysaccharides and were able to increase proliferation and insulin secretary function of rat insulinoma RINm5F cells, in a dose-dependent manner. In addition, EPS also strikingly reduced the streptozotocin-induced apoptosis in RINm5F cells indicating the mode of the cytoprotective role of EPS on RINm5F cells.
authors.affiliation: Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk, 712-714, South Korea.
authors.forename: Hee Sun
authors.initials: HS
authors.lastname: Hwang
authors.forename: Sung Hak
authors.initials: SH
authors.lastname: Lee
authors.forename: Yu Mi
authors.initials: YM
authors.lastname: Baek
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Yong Kee
authors.initials: YK
authors.lastname: Jeong
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Yun
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000378:metabolism*; D008903:Minerals / Q000378:metabolism; D025282:Mycelium / Q000254:growth & development / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D020072:Polyporales / Q000254:growth & development / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D013311:Streptozocin / Q000494:pharmacology; D013696:Temperature
chemical_list: D006131:Growth Inhibitors; D007328:Insulin; D008903:Minerals; D011134:Polysaccharides; D013311:Streptozocin; D002244:Carbon; D009584:Nitrogen