Abstract Description

This study reports a novel fibrinolytic enzyme produced by Bacillus tropicus DUT M1, isolated from the traditional South African fermented beverage mahewu. A comprehensive optimisation strategy was employed by combining one-factor-at-a-time (OFAT) and response surface methodology (RSM), which included the Plackett–Burman design and Central Composite Design (CCD), to enhance enzyme production. The optimised conditions obtained were: casein (28.23 g/L), meat extract (6.41 g/L), and a pH of 7.90, which resulted in a 13.9-fold increase in enzyme yield, from 12 U/mL to 167 U/mL. Enzyme kinetics were modelled using four mathematical growth functions, with the S-Gompertz model providing the best fit (R² = 0.977). The enzyme demonstrated robust fibrinolytic activity at physiological conditions (37°C, pH 7.5), with the potential to cleave clots in vitro. These findings highlight the scalability and therapeutic potential of microbes isolated from African fermented foods as untapped reservoirs of fibrinolytic enzymes, paving the way for future biopharmaceutical and industrial applications.