Captura cromatográfica de L-asparaginase fúngica usando criogel de troca iônica: uma estratégia para mitigação de acrilamida em alimentos

Abstract

L-asparaginase (ASNase) is an enzyme of interest in the food industry because it catalyzes the hydrolysis of L-asparagine into aspartic acid and ammonia, contributing to the reduction of acrylamide formation, a potentially carcinogenic compound generated during the thermal processing of foods. Filamentous fungi stand out as promising sources for the production of this enzyme due to their high productivity, stability, and ease of cultivation. However, even partial purification of the enzyme is essential for its use in food applications. In this context, cryogels emerge as potential chromatographic supports for the purification of biocompounds, particularly from crude and non-clarified extracts. Therefore, the present study aims to develop ion-exchange cryogels for the purification of ASNase from Aspergillus caespitosus, cultivated via solid-state fermentation using ora-pro-nobis (Pereskia aculeata Miller) fiber as substrate. The cryogels were synthesized by cryo-copolymerization (–12 °C, 24 h) and subsequently functionalized with amino acids (taurine, cysteine, or glutamic acid) via epoxy method or using glutaraldehyde. The cryogel functionalized with taurine and activated with glutaraldehyde (cryo-Tau) showed the highest adsorption capacity (83.43 mg g−1) for the enzymes at pH 7.0, which may be attributed to electrostatic interactions between ASNase and the functional groups of cryo-Tau, since the point of zero charge (pHpzc) of this adsorbent was 7.45. Cryo-Tau exhibited high porosity (>90%), swelling capacity (12.99 g g−1), thermal stability (up to 250 °C), mechanical strength (18.78 kPa), total ionic capacity of 26.40×10−3 molNa+ L−1 hydrated cryogel, and amorphous behavior with a glass transition temperature of 6.62 °C. The purified enzyme showed optimal activity at 40 °C and pH 7.0, with specific activity of 143.93 U mg−1, purification factor of 2.65, and recovery of 73.99%. The cryogel maintained effective performance for up to six reuse cycles. When applied to potato chips, ASNase reduced acrylamide levels by up to 52% after 60 minutes of treatment. These results demonstrate the potential of cryo-Tau for enzyme purification, enabling its subsequent application in food systems.