Immobilization of the Tannase From Aspergillus fumigatus CAS21: Screening the Best Derivative for the Treatment of Tannery Effluent Using a Packed Bed Reactor.

Rayza Morganna Farias Cavalcanti,Luis Henrique Souza Guimarães,Chadia Chahud Maestrello

doi:10.3389/fbioe.2021.754061

Rayza Morganna Farias Cavalcanti, Luis Henrique Souza Guimarães + Show 1 more

Open Access

https://doi.org/10.3389/fbioe.2021.754061

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Abstract

Enzyme immobilization is an important alternative to stabilize enzyme properties favoring the efficiency of derivatives (enzyme + support/matrix) for different purposes. According to this, the current study aimed to immobilize the Aspergillus fumigatus CAS21 tannase and the use of the derivatives in the treatment of the effluent produced by the tannery industry. The tannase was immobilized on sodium alginate, DEAE-Sephadex, amberlite, and glass pearls as supports. Calcium alginate was the most adequate support for tannase immobilization with 100% yield and 94.3% for both efficiency and activity. The best tannase activity for the calcium alginate derivative was obtained at 50°C–60°C and pH 5.0. Thermal and pH stabilities evaluated for 24 h at 30°C–60°C and pH 4–7, respectively, were improved if compared to the stability of the free enzyme. Considering the reuse of the calcium alginate derivative, 78% of the initial activity was preserved after 10 catalytic cycles, and after the 9-month storage at 4°C, the activity was maintained in 70%. This derivative was applied in a packed bed reactor (PBR) for the treatment of tannin-rich effluents from the tannery industry. The reduction of the tannin content was effective reaching degradation of 74–78% after 48 h of PBR operation. The concentration of total phenolic compounds was also reduced, and the color and clarity of the effluent improved. In conclusion, the calcium alginate derivative is an attractive alternative as biocatalyst for large-scale treatment of the effluents from the tannery industry.

Highlights

The manufacture of leather is one of the most widespread processes worldwide due to the fact that it is an input in the industries of footwear, clothing, accessories, furniture, and automotive items (Dixit et al, 2015)
The second best derivative was the Mn-alginate with 100% yield, efficiency of 81.3, and 81.3% recovered activity. These results indicate that the enzyme was efficiently encapsulated in the alginate beads and no activity was detected in the supernatant
It is important to highlight that the results obtained for A. fumigatus CAS21 tannase immobilization in alginate beads were more expressive than those observed for the other supports used

Summary

Introduction

The manufacture of leather is one of the most widespread processes worldwide due to the fact that it is an input in the industries of footwear, clothing, accessories, furniture, and automotive items (Dixit et al, 2015). The preparatory phase is cleaning the leather and eliminating parts that will not be used, such as removing the animal hair (Dixit et al, 2015; Mosca Angelucci et al, 2017). Vegetable/synthetic tannins or mineral agents (aluminum, chromium, and zirconium) are applied in order to avoid skin putrefaction (Laurenti et al, 2016). These compounds provide greater durability of leather and stabilization of the collagen present in animal skin, avoiding chemical, thermal, and microbiological degradation (Onem et al, 2015). The finishing stage includes rinsing the tanned leather, drying, cutting, and concluding the final aspects to improve its commercial value (Mosca Angelucci et al, 2017)

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