For folic acid production, two LAB Lactobacillus acidophilus (L. acidophilus) in addition Bifidobacterium longum (B. longum) were exposed to UV irradiation for mutagenesis in relation to folate productivity and anti-inflammatory activity.

The results indicated that, fifty mutants were tested towards their folate productivity, four mutants only have productivity higher than Wild strains G5 and K1 resulted from B. longum with productivity 68.8 and 56.2% of wild type productivity. Likewise, two mutants of L. acidophilus were A2 and C4 with folate productivity 205.2 and 289.3% respectively of Wild type productivity.

Results of docking study showed the mode of binding folic acid demonstrated energy binding of of -8.65 kcal/ mol. against DHFR. Folic acid formed four Pi-alkyl, Pi-Pi In addition to Pi-sigma relationships with Ala9, Ile7, Phe34 and Ile60. Additionally, Folic acid interacted with Glu30 and Asn64 through three hydrogen bonds is 1.77, 1.76, In addition to 1.96 Å. The top four UV-mutants was chosen also showed anti-inflammatory activity determined through inhibiting of COX-1 and COX-2 activity higher than both their wild strains and Celecoxib, mutant A2 was the best in inhibiting COX-1 activity at 8.4µg/ml, while mutant C4 was the best in inhibiting COX-2 activity of 0.030 µg/ml. At the level of FolE gene expression, mutant A2 had the highest gene with 1.4fold, followed by mutant K1 with 1.02, then mutant G5 with 0.97 and all these three mutants have expression of gene higher than those of the two genuine strains.

It could be concluded that, Bifidobacterium longum and Lactobacillus acidophilus were genetically improved with regard to their folic acid productivity and anti-inflammatory activity through UV mutagenesis, that resulted in four mutants have productivity higher than Wild strains. Also, the four mutants have anti-inflammatory activity through inhibiting of COX-1 and COX-2 activity. Molecular docking was performed to confirm theoretically the role of folic acid in DNA synthesis and repair. The results of the docking investigation revealed that the energy binding of folic acid to DHFR was -8.65 kcal/mol. With folic acid, Ala9, Ile7, Phe34, and Ile60 produced four Pi-alkyl, Pi-sigma, and Pi-Pi interactions. Additionally, three hydrogen bonds between folic acid and Glu30 and Asn64, with separations of 1.77, 1.76, and 1.96, were formed.