Optimization of a bioactive exopolysaccharide production from endophytic Fusarium solani SD5
ABSTRACT Endophytic fungi were less investigated for exopolysaccharide production. In this study endophytic Fusarium solani SD5 was used for optimization of exopolysaccharide production. One variable at a time method and response surface methodology were employed to explore the optimum medium compositions and fermentation conditions. The organism produced maximum exopolysaccharide after 13.68 days of incubation at 28°C in potato dextrose broth supplemented with (g%/l) glucose, 9.8; yeast extract, 0.69; KCl, 0.05; KH2PO4, 0.05 with medium pH 6.46. Use of 50ml medium in 250ml Erlenmeyer flask gives highest exopolysaccharide production. The organism produced more than two times higher exopolysaccharide (2.276±0.032g/l EPS) at optimized condition compared to pre-optimized condition (0.96±0.021). In vivo toxicity test established nontoxic nature of the EPS (≤400mg EPS/Kg of body weight). The EPS slightly altered intestinal indigenous bacteria and influenced the growth of beneficial Lactobacillus spp.
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ABSTRACT: This study examines the production, characterization and bioactivity on plant cell cultured in vitro of exopolysaccharides (EPS) from Syncephalastrum racemosum CBS 443.59. Firstly, the influence of the fungus culture condition in shake flasks (pH, temperature and different carbon and nitrogen sources) on EPS and biomass production was evaluated. In order to enhance EPS production, a new protocol based on two-stage pH fermentation in a 3L stirred fermentor was developed. Under this condition, EPS production increased by 3.55 times, compared to a constant pH process, reaching a maximal EPS concentration of 2.62g/L. Structurally, the EPS contains a polyglucuronic acid backbone, linked essentially with mannose and fucose units and some galactose and glucose units. The bioactivity of EPS as inducer of defence reactions in plant suspension-cultured cells was also studied. Our results show, for first time, that EPS from S. racemosum CBS 443.59 induces, depending on the concentration, PAL activation and H2O2 synthesis in Arabidopsis thaliana cell suspensions.01/2014; 101:941-6. DOI:10.1016/j.carbpol.2013.10.018
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ABSTRACT: In this study, a sulfated polysaccharide with a high molecular weight was isolated from sea cucumber Holothuria nobilis. It is a fucosylated chondroitin sulfate and being named as HOP. We investigated the effects of several processing variables on the oxidative degradation of HOP using fractional factorial design (FFD) and central composite design (CCD). Moreover, the conditions of the hydroxyl free radical-induced degradation were optimized using response surface methodology (RSM). Our data showed that R(H2O2-HOP), reaction pH and H2O2 flow rate could significantly (P < 0.05) affect the degree of hydrolysis (DH) of HOP. The optimum conditions with Fe2+ were found as follows: R(H2O2-HOP) of 0.53; reaction pH of 6.91; H2O2 flow rate of 0.40 mL/min; reaction time of 2 h; reaction temperature of 30 °C; and HOP concentration of 4 mg/mL. Under these optimum conditions, the DH of HOP was 94.173 ± 0.232 (%), which well matched the value (94.152%) predicted by the RSM model. The preliminary structural characterization of o-HOP was analyzed. The results showed that o-HOP consisted of β-D-glucuronic acid, β-D-N-acetyl-galactosamine, α-L-fucose and sulfate groups. The speciﬁc rotation of o-HOP was -43.2°. Furthermore, the sulfation patterns of fucose residues in o-HOP were 2,4-O-disulfated fucose, 3-O-sulfated fucose, 4-O-sulfated fucose and non-sulfated fucose, which were consistent with HOP. In addition, we found that the in vitro antitumor activity of the degraded HOP fraction (o-HOP) was higher than that of HOP against human gastric carinoma SGC-7901 cells.PROCESS BIOCHEMISTRY 12/2014; 50(2). DOI:10.1016/j.procbio.2014.12.016 · 2.52 Impact Factor