Abstract
This research represents a novel study to assess how coculture affects levan yield, structure, bioactivities, and molecular weight. Among the 16 honey isolates, four bacterial strains recorded the highest levan yield. The Plackett-Burman design showed that the coculture (M) of isolates G2 and K2 had the maximum levan yield (52 g/L) and the effective factors were sucrose, incubation time, and sugarcane bagasse. The CCD showed that the most proper concentrations for maximum levan yield (81 g/L): were 130 g/L of sucrose and 6 g/f of sugarcane bagasse. Levan's backbone was characterized, and the molecular weight was determined. G2 and K2 isolates were identified based on 16 sRNA as Bacillus megaterium strain YM1C10 and Rhizobium sp. G6-1. M levan had promising antioxidant activity (99.66%), slowed the migration activity to a great extent, and recorded 70.70% inhibition against the hepatoblastoma cell line (HepG2) at 1000 µg/mL. Gene expression analysis in liver cancer cell lines (HePG2) revealed that M levan decreased the expression of CCL20), 2GRB2, and CCR6) genes and was superior to Doxo. While increasing the expression of the IL4R and IL-10 genes. The DNA damage values were significantly increased (P < 0.01) in treated liver cancer cell lines with levan M and Doxo. The results referred to the importance of each of the hydroxyl and carboxyl groups and the molecular weight in levans bioactivities.