Production of water‐soluble sulfated exopolysaccharide with anticancer activity from Anoxybacillus gonensisYK25

Abstract

BACKGROUND Thermophilic bacteria are accepted as novel sources of exopolysaccharides (EPSs) with different biological activities. This study was conducted to test EPS production potential of thermophilic bacteria isolated from hot springs in Erzurum province (Turkey), to optimize EPS production from the best isolate in molasses medium, to characterize the produced EPS, and to investigate its anticancer activity. RESULTS Among 28 isolates, the best EPS producer isolate was found to be Anoxybacillus gonensis YK25 (GenBank No: MN865832). Under optimized culture conditions (initial pH 7.0, temperature 55 °C, molasses concentration 100 mL/L, peptone concentration 6 g/L, and incubation time 96 h), 4.4 g/L EPS was produced. Molecular weight of EPS was 102 kDa. Carbohydrate and protein contents of EPS were 91.4% and 4.1%, respectively. EPS was a heteropolysaccharide containing xylose (59%), sucrose (18%), glucose (16%), and galactose (5%). It had a high solubility in water and a moderate solubility in dimethyl sulfoxide (DMSO), but it was insoluble in polar solvents. FTIR analysis confirmed the presence of hydroxyl, carboxyl, amide, and sulphate groups. EPS showed anticancer activity against SHSY‐5Y, HT‐29, DU‐145, and A‐549 cell lines in a dose‐dependent manner. The IC50 values of EPS for A‐549, DU‐145, SHSY‐5Y, and HT‐29 cancer cells were 5.5, 9.61, 15.62, and 17.35 mg/mL, respectively. CONCLUSION The EPS production potential of A. gonensis, and the anticancer activity of the produced EPS were revealed. Furthermore, it was shown for the first time that the main monomer of bacterial heteropolysaccharides would be xylose. This study indicates that Anoxybacillus species may be a novel source of pharmaceutically‐important EPSs. © 2020 Society of Chemical Industry

Exopolysaccharide Produced by Probiotic Bacillus albus DM-15 Isolated From Ayurvedic Fermented Dasamoolarishta: Characterization, Antioxidant, and Anticancer Activities

“…Antiproliferative or cytotoxic activity is quite common in sulfated EPS. For example, EPS from Anoxybacillus gonensis YK25 showed considerable anticancer activity against lung cancer cells ( Karadayi et al, 2021 ). The EPS used in this study also possess the sulfate content, which might be responsible for the cytotoxic activity.…”

“…For example, sulfate groups in the bacterial EPS are considered potential lead for the antiproliferative, anticoagulant, fibrinolytic, antimicrobial, prebiotic, and wound-healing properties ( Haroun-Bouhedja et al, 2000 ; Ruiz-Ruiz et al, 2011 ; Almutairi and Helal, 2021 ). Sulfated exopolysaccharide purified from the Anoxybacillus gonensis YK25 showed significant anticancer activity against the lung cancer cells ( Karadayi et al, 2021 ). In addition, sulfated EPS (levan) derived from the Bacillus megaterium PFY-147 had shown free radical scavenging activity, antioxidant and probiotic activities, which validate the potential implications of sulfated EPS in biomedical applications ( Pei et al, 2020 ).…”

Molecular Characterization and Biocompatibility of Exopolysaccharide Produced by Moderately Halophilic Bacterium Virgibacillus dokdonensis from the Saltern of Kumta Coast

“…Weak peaks around 1448.54 cm −1 and 1421.54 cm −1 are attributed to bending vibrations of C-H bonds. However, there are reports that these may also be associated with stretching vibrations of COO– groups [ 60 , 61 ]. Additionally, the stretching of sulfate groups appears in the region 1100 to 1150 cm −1 [ 44 , 62 ]; thus, the band at 1114.86 cm −1 may indicate the possible presence of sulfate groups.…”

“…The water solubility value of VITP14 EPS is 76.5% at 500 mg/mL, indicating that the EPS has good water solubility at a higher concentration and is better than the EPS produced by the thermophilic bacterium Anoxybacillus gonensis YK25, whose water solubility is 76% at 100 mg/mL [ 61 ]. Several factors such as glycosidic linkage, chain length, and structural arrangements affect the water solubility of EPSs [ 50 ].…”

Characterization and in vitro anticancer potential of exopolysaccharide extracted from a freshwater diatom Nitzschia palea (Kütz.) W.Sm. 1856

“…However, EPS derived from marine bacteria such as Brevundimonas subvibrioides, Bacillus thuringiensis, B. amyloliquefaciens, Pseudomonas fluorescens , and Advenella kashmirensis constitute sulfated groups in their monosaccharide units and had shown anti-proliferative activity on liver cancer cells HepG2 9 . An EPS from a thermophilic bacterium Anoxybacillus gonensis YK25 isolated from the hot springs of Turkey hampered the proliferation rate of tumor progression in metastatic bone tumors (SHSY5Y), human colon cancer (HT29), prostate cancer (DU145), and human lung cancer A549 10 . Bacterial EPS was reported with anticancer potential, whereas, EPS from diatoms (Bacillariophyceae) is unexplored.…”