Functional superiority and robust stability of biosurfactants from a bacillus-pseudomonas consortium cultivated on Cola hispida pod Agro-waste

For biosurfactants to transition from laboratory discoveries to industrially viable products, two critical factors must be addressed: cost-effective production and demonstrably superior, stable performance. This study aimed to produce, quantify, and characterize the functional performance and stability of biosurfactants synthesized by a Bacillus sp., a Pseudomonas sp., and a defined consortium of both, using Cola hispida pod a validated agro-waste substrate in submerged fermentation. Following acid precipitation and extraction, biosurfactant activity was rigorously assessed through standard assays. The consortium-produced biosurfactant demonstrated exceptional efficacy, achieving the highest emulsification index (E₂₄) of 73.33% with kerosene, the largest oil displacement diameter (3.23 cm), and the most significant reduction in surface tension (to 38.0 mN/m). A pivotal finding was that the medium containing solely Cola hispida pod as the nutrient source consistently yielded biosurfactants with superior emulsifying activity compared to media supplemented with pure glucose or commercial nutrients. All biosurfactants exhibited remarkable resilience, retaining over 50% emulsification capacity across a wide pH spectrum (2–10), at elevated temperatures up to 90°C, and in the presence of high NaCl concentrations (up to 10% w/v). These results highlight two transformative insights: firstly, the engineered microbial consortium exhibits clear synergistic interaction, producing a biosurfactant with enhanced functional properties compared to its constituent monocultures. Secondly, Cola hispida pod is not merely an alternative but a preferable, low-cost substrate for generating high-performance, industrially robust biosurfactants. This work validates an integrated sustainable platform for producing potent, stable surfactants suitable for demanding applications in environmental remediation, enhanced hydrocarbon recovery, and formulation chemistry.