پریسا فتحی رضایی

The novel kappa carrageenan-chitosan nanomagnetics (CCMNs) and chitosan-pectin nanomagnetics (CPMNs) were synthesized via situ co-precipitation and characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) methods. The highest Piriformospora indica exo-polygalacturonase (exo-PG) specific activity (32.48 U/mg) was monitored on pectin-containing YPG medium after 4 days of incubation. Then, exo-PG were purified and immobilized by CCMNs and CPMNs. The enzyme attached to the nanomagnetic carriers by physical adsorption. The purified Exo-PG had an apparent molecular weight of 60 kDa which illustrated maximal activity at pH 6.0 and 40 ◦C. The specific activity of the purified enzyme by CCMNs and CPMNs was determined 479 U/mg and 204 U/mg, respectively. Exo-PG immobilized on CPMNs had a recovered activity of 71.11 % with an immobilization yield of 89.15 %. Furthermore, CCMNs-PG exhibited recovered activity of 65.96 % with an immobilization yield of 63.85 %. Moreover, the immobilized Exo-PG on CPMNs and CCMNs beads retained 72 % and 60 % of respectively their initial activity after 6 successive cycles. Overall, findings of this investigation might open new insights to apply nanomagnetics for exo-PG purification and immobilization in food industries.