Economic analysis of the production and recovery of green fluorescent protein using ATPS-based bioprocesses

Abstract

Green fluorescent protein (GFP) is a useful biomolecule in biotechnology; however, its price makes its widespread application prohibitive. To overcome this issue, recently, the use of aqueous two-phase systems (ATPS) for GFP purification was proposed as an alternative platform to reduce processing costs. Aligned with this goal, this study performed bioprocess modelling coupled with economic analysis using the software Biosolve to evaluate the potential and commercial applicability of ATPS for GFP purification. This work analysed a collection of fourteen ATPS to discriminate through production costs while also incorporating the concept of product purity into the calculations. The two best systems (a PEG-based and an ionic liquid (IL)-based ATPS) were placed in a full bioprocess at different scale models (1 to 100 L) to elucidate the viability of applying ATPS at large scale. Although the results showed that the PEG-based ATPS exhibit the lowest costs (between USD 3.5x10(3).g(-1) at 1 L and USD 0.33x10(3).g(-1) at 100 L), for further developments, the inclusion of an ATPS granting a higher purity is desired for the development of simpler bioprocesses. Therefore, as a third approach in this work, a sensitivity analysis was performed to determine the impact of varying different model parameters (recovery yield, material costs discount and production titre), to elucidate the circumstances under which the IL-based system can overcome the production costs of the traditional PEG-based ATPS. The results indicate that the best cost-effectiveness approach is to improve the production titre (although it can affect all ATPS studied), as an increase from 1.33 to 3.8 g/L is enough for the IL-based ATPS to be less expensive than the traditional system at all analysed scales. This study demonstrates that ATPS can greatly reduce GFP manufacturing costs, which can potentially help to popularize new applications of fluorescent proteins that are currently mostly restricted to research kits due to their high prices.