Abstract

Adeleke GE75319*, Berena GA75320, Ayobami TE75321, Owolabi OQ75322, Adeyi RO75323, Owoseni AA75324, Atobatele BO75325, Isere VI75326, Elegbede AJ75327, Magaji MS75328, Kalba DM75329, Musa EJ75330, Ibrahim HS75331, Adeleke JM75332, Imam MO75333 and Ilomuanya CS75334

Bacillus is a gram-positive bacterium, with potential to synthesize several enzymes and secondary metabolites. Soybean (Glycine max) is a leguminous edible seed that is highly rich in proteins and other nutrients. This study chemically elucidates the various antibiotics produced by soil Bacillus during the fermentation of soybean seeds.

Bacillus species were isolated from a soil sample on sterilized nutrient agar and tested by gram staining and starch hydrolysis. Dried seeds of Glycine max were mechanically ground to obtain Glycine Max Seed Powder (GMSP). Fermentation of GMSP was carried out in a 250 mL Erlenmeyer flask for 192 hours. The time-courses of antibiotic production like peptide, macrolide and fluoroquinolone in fermentation broths were monitored spectrophotometrically every 24 hours, while High Performance Liquid Chromatography (HPLC) was used to analyze the antibiotics in the broths. Whitish bacterial colonies Bacillus formed were positive for gram staining and starch hydrolysis. Time-course analysis showed highest concentrations of peptide, macrolide and fluoroquinolone antibiotics at 117.16 µg/mL, 342.57 µg/mL and 2584.81 µg/mL, respectively in the broths. The HPLC indicated formation of bacillomycin D, surfactin A and 1-deoxynojirimycin as major antibiotics in GMSP broth. This study demonstrates that Bacillus species can synthesize antibiotics from soybean seeds, an innovation that extends the economic value of this food crop.