Efficient Immobilization of <i>Streptomyces gobitricini</i> Lipase for Sustainable Lipid Degradation and Wastewater Bioremediation

Immobilized lipases are emerging as highly effective biocatalysts due to their enhanced operational stability, reusability, and promising environmental applications, particularly in the bioremediation of lipid-contaminated wastewater. In this study, the lipase from <i>Streptomyces gobitricini</i> (Lip_S.g) was immobilized on various supports, with calcium carbonate demonstrating the highest immobilization efficiency (82.66 ± 5.5%). Optimal conditions were achieved using a lipase concentration of 3500 U·g^-1 support, resulting in a retained activity of 92.67 ± 3.05%. The immobilized Lip_S.g showed significantly improved storage stability, maintaining 68.33% of its initial activity after 120 days at 4 °C, compared to only 29.7% for the free enzyme. It also exhibited greater tolerance to alkaline pH and high temperatures, with maximum activity at pH 9.0 and thermal stability up to 70 °C. Substrate specificity tests on oil-based substrates revealed improved catalytic performance in the immobilized form, likely due to enhanced substrate accessibility. In practical wastewater treatment trials, the immobilized enzyme achieved complete lipid removal by day 9, in contrast to the free enzyme, which achieved only 50% removal. Moreover, marked reductions in chemical oxygen demand and residual lipid levels further validated its bioremediation efficacy. These results position immobilized Lip_S.g as a robust, eco-friendly biocatalyst with strong potential for industrial applications in the treatment of oil-laden wastewater.