Antimicrobial and antioxidant characteristics of exopolysaccharides produced by Agrobacterium tumefaciens Cs5 and T1 | ||
| Egyptian Journal of Chemistry | ||
| Article 22, Volume 63, Issue 11, November 2020, Pages 4423-4438 PDF (1012.64 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejchem.2020.26635.2542 | ||
| Authors | ||
| Mohamed A. Moselhy; Fatma Shams Lotfy* ; Hussein E. Makboul; Abdallah S. Ali | ||
| Microbiology Department, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt | ||
| Abstract | ||
| This work was conducted to isolate and screen for bacteria that producing higher quantities of exopolysaccharides (EPSs) from the Egyptian soils. Forty soil samples were collected from different regions of three Governorates (Beheira, Giza, and Qalyubia). A total of 165 bacterial isolates were obtained from the soil rhizosphere. Thirty-five of them (21.2%) had ability to produce stable ropy colonies. After screening, two isolates Cs5 and T1 were selected for further study according to their capacity to produce a high quantity of EPS (7.1 and 5.7 g/l, respectively). The selected bacterial isolates were identified as non-similar strains of Agrobacterium tumefaciens based on their morphological, biochemical characteristics as well as 16S rRNA gene sequencing. To obtain maximum EPS production of both strains, nutritional and cultivation parameters were optimized using the one-factor-at-a-time method. Thus, the maximum EPS yield of 21.63 and 19.57 g/l were achieved from the strains Cs5 and T1, respectively. When molasses and corn steep liquor were substituted the synthetic carbon and nitrogen sources as low cost-substrates, EPS yields were improved to be 28.73 and 24.5 g/l for Cs5 and T1, respectively. The infrared (FT-IR) spectra for both extracts revealed the typical patterns of polysaccharide absorption. Moreover, HPLC analysis demonstrated that EPSs were heteropolysaccharide composed of glucosamine, glucose, and fructose. The produced EPS showed antioxidant capacity as well as strong antibacterial activity against Staphylococcus aureus (methicillin-resistant) and Bacillus cereus as hazardous human pathogens, suggesting their application in the food industry. While the produced EPS did not affect cancer cells. | ||
| Keywords | ||
| Agrobacterium tumefaciens; exopolysaccharides; optimization; antibacterial; antioxidant; and soil | ||
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