Techno-economic analysis of laccase production, immobilization and use of the immobilized biocatalyst in hospital wastewater bioremediation

Abstract

In this study, cost analyses were performed to assess the economic feasibility and the competitiveness of a combined bioprocess for the production of a T. hirsuta laccase under submerged fermentation, immobilization of the crude enzyme and use of the formulated biocatalyst for hospital wastewater treatment. The laccase was immobilized on an amino-functionalized silica microsphere attached to a polyethylene scaffolding. Capital (CapEx) and operational (OpEx) expenses were calculated for each step of the process, considering the cost of equipment, raw materials, workload and utilities. For laccase production, labor cost represented the highest contributor to the total cost (51.6 %), followed by the equipment cost (42.2 %), while the costs of raw materials and energy were significantly low at 5.0 % and 1.1 %, respectively. The cost of the crude laccase was estimated to be 3.90 CAD (2024) kU⁻¹. In the immobilization step, the cost of raw materials represents the major cost contributor with 89.9 % due to the important cost of the immobilization support, while labor accounted for 6.4 %, equipment 3.6 % and energy 0.1 %. Sensitivity analyses were performed to investigate the cost dynamics with respect to the number of laccase production batches, the cost of raw materials, electricity, and labor. The cost of pilot-scale wastewater treatment using the formulated biocatalyst, taking into account a less expensive but similar immobilisation support, was estimated to be 0.87 CAD (2024) m⁻³, which is a reasonable cost but can be further reduced after the process optimization.