Fermentation of Wild Hydrolytic Bacteria Isolated from Opuntia ficus-indica, and Its Effect on Flow Behavior of Cladodes Flour Culture Media

The aim of this study was to evaluate the fermentation dynamics of two wild hydrolytic microorganisms and their effect on the flow behavior of a culture medium formulated with Opuntia ficus-indica cladode flour. Identified Acinetobacter pitti and Bacillus subtilis presented maximum values of specific hydrolytic activity (SHA) at 24 h of growth (0.21 ± 0.05 and 0.22 ± 0.01 IU, respectively). The apparent viscosity of cladode flour medium (CFM) measured by applying shear rates (66.7 s−1–0.003 s−1) in suspensions (20%) showed a significant decrease (60%) as a function of bacterial growth progressed. After fermentation, the CFM exhibited pseudoplastic (shear-thinning) behavior, which was linked to the enzymatic degradation of polysaccharides. The use of crude extracellular enzyme extracts from these wild bacteria effectively reduced medium viscosity by breaking down the plant matrix. These findings highlight the hydrolytic potential of native strains in modifying the rheological properties of cactus-based culture media, offering a low-cost alternative for biomass pretreatment and valorization in future biotechnological applications.