Comprehensive Study of Biodiesel Production from Soybean Oil with Intensified Enzymatic Degumming and Adsorptive Purification

The production of high-quality biodiesel from vegetable oils requires an integrated approach that considers feedstock quality, transesterification, and final product purification. This study investigates a comprehensive technological sequence for soybean biodiesel production combining enzymatic degumming, treatment with biosurfactant-containing microbial culture fluid, cavitation-assisted transesterification, and adsorptive dry purification. Enzymatic pretreatment using the multienzyme preparation Purifine® 3G in combination with culture fluid obtained from Pseudomonas fluorescens cultivation was associated with reductions in residual phosphorus and sulfur contents and acid value, potentially due to improved enzyme-substrate interactions, although increasing the culture-fluid dosage prolonged phase separation. Cavitation-assisted transesterification produced biodiesel with a higher fatty acid methyl ester (FAME) mass fraction than conventional stirred-reactor processing under the investigated operating conditions, while spectroscopic and chromatographic analyses confirmed the formation of products with similar FAME profiles. A comparative evaluation of three purification schemes demonstrated that direct adsorptive dry purification using natural clinoptilolite provided the highest FAME mass fraction without requiring an additional water-washing step. Industrial-scale testing confirmed the applicability of clinoptilolite-based adsorptive conditioning for reducing residual water content while maintaining a high ester content. Overall, the findings support the technical feasibility of integrating enzymatic feedstock pretreatment, transesterification, and adsorptive conditioning into soybean biodiesel production and identify key aspects for further process optimization and industrial validation.