Microfiltration of micelles from fermentation of "Streptomyces tsukubaensis" for the production of tacrolimus

Abstract

Tacrolimus is a drug recommended as immunosuppressant for kidney and liver transplant therapy, treatment of autoimmune diseases, rheumatoid arthritis and lichen planus, as well as in the treatment of bronchial asthma, dermatological disorders such as vitiligo, psoriasis, atopic dermatitis, eye diseases such as uveitis and in the treatment of patients with idiopathic membranous nephropathy. This Dissertation aims to improve the tacrolimus recovery process through the development of a pressurized column for fermented broth microfiltration from fermentation via Streptomyces tsukubaensis, which contains tacrolimus, so that the micelles present in the broth are retained with 95 % rejection at least. Fermentation runs were carried out using coconut oil and glucose as carbon sources, obtaining the specific production of the drug equal to 1.88 mg/g and 1.69 mg/g, respectively. In addition to identifying and quantifying the drug, it was possible to quantify the biomass, sugars, and proteins from fermentation. In view of the need to evaluate the performance of the proposed system, addressed to the removal of micelles, an alternative technique was developed that associates the particle counting by the Neubauer chamber with the spectroscopy technique, making it possible to associate the number of particles with the absorbance. In addition, a study was carried out on the rheology of raw broth fermented with acetone submitted to microfiltration, verifying non-Newtonian behavior, of a pseudoplastic nature, significantly for temperatures above 30 °C. Regarding the performance of microfiltration, the performance of two membranes, 0.22 µm and 3.00 µm of average pore diameter, were subjected to operating pressures of 1 bar and 2 bar. It was found that a simple batch of microfiltration was not enough to achieve 95 % removal. Thus, the strategy of multiple steps of the permeate through the filter was established, obtaining the desired removal in 6 passages, and the maximum rejection obtained from the micelle was 97%, achieved in ten steps. This performance was achieved with 3.00 µm membrane, using 1 bar operating pressure. It was observed that the permeate volumetric flow decreases with the increase in the steps number until it remains constant. This behavior is observed with the total resistance of the filter medium, which remains constant after a certain step, but, before, the total resistance increases with the steps number. It should be noted that, given the scope of the application of tacrolimus and its distribution by the Brazilian Unified Health System (SUS), the dimension of its production for society was contextualized, emphasizing the importance of hope as essential element in the chemical project of obtaining of the drug, concluding that it is possible to do science and develop innovative technology with a strong social commitment.