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Several antiviral agents lost their efficacy due to their severe side effects and virus mutations. This study aimed to identify and optimize the conditions for exopolysaccharide (EPS) production from a newly isolated cyanobacterium, Acaryochloris Al-Azhar MNE ON864448.1, besides exploring its antiviral activity. The cyanobacterial EPS was purified through DEAE-52 cellulose column with a final yield of 83.75%. Different analysis instruments were applied for EPS identification, including Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and gas chromatographic-mass spectrometry (GC–MS). Plackett–Burman's design demonstrated that working volume (X1), EDTA (X2), inoculum size (X3), CaCl2 (X4), and NaCl (X5) are the most important variables influencing EPS production. Central composite design (CCD) exhibited maximum EPS yield (9.27 mg/mL) at a working volume of 300 mL in a 1 L volumetric flask, EDTA 0.002 g/L, inoculum size 7%, CaCl2 0.046 g/L, and NaCl 20 g/L were applied. EPS showed potent antiviral activities at different stages of herpes simplex virus type-1 and 2 (HSV-1, HSV-2), adenovirus (ADV) and coxsackievirus (A16) infections. The highest half-maximal inhibitory concentration (IC50) (6.477 µg/mL) was recorded during HSV-1 internalization mechanism, while the lowest IC50 (0.005669 µg/mL) was recorded during coxsackievirus neutralization mechanism. [ABSTRACT FROM AUTHOR]

BACKGROUND: Biosurfactants are surfactants derived from several types of microorganisms such as bacteria, yeasts and fungi as membrane components or secondary metabolites. OBJECTIVE: To increase BS productivity as a biocompatible, low-toxic substitute for chemical surfactants employed in modern industry and the huge variety of applications they are used in. METHODS: Different media were used in isolation of the biosurfactant BS producers. The most potent bacterial isolate was analysed by 16S-rRNA. Plackett Burman and Box-Behnken Designs were used for optimization conditions. BS was purified by and characterized. RESULTS: Only one strain demonstrated great BS productivity, excellent emulsifying capability (54.5±0.1%) and oil spreading activity which analysed as Bacillus cereus AHMNAZ1 with accession number OP714421.1. The BS was lipopeptide in nature, identified as a surfactin which was stable and has Critical Micelle Concentration of 60 mg/L. Isolated surfactin showed excellent activity against Colon Carcinoma and Breast Carcinoma cell lines and can be used as antimicrobial agent. CONCLUSION: The study found a cheaper way of creating biosurfactants from agro-industrial wastes, delivering a twofold benefit of lowering environmental pollution and manufacturing useful biotechnological products (biosurfactants) with high activity and thermostability. Moreover, it can be used for the bioremediation of oil-polluted soils and in medical fields. [ABSTRACT FROM AUTHOR]