Reactive & Functional Polymers ( IF 5.1 ) Pub Date : 2020-07-29 , DOI: 10.1016/j.reactfunctpolym.2020.104696 Marwa I. Wahba
β-D-Galactosidase (β-gal), a crucial enzyme in food industries, was immobilized onto egg white protein (EWP) based covalent immobilization carriers of escalated mechanical stability. This escalated mechanical stability was acquired after incorporating the mechanically stable calcium gelled gellan gum (GG) beads. The EWP established a coating layer around the gellan gum (GG) beads, and the EWP-GG beads were then processed with glutaraldehyde (GA). The preparation process of the GA-EWP-GG beads was optimized, and it was disclosed that the optimum EWP pH, EWP concentration, and GA concentration were 2–4, 7% (w/w), and 20–25% (v/v), respectively. β-Gal was immobilized onto the GA-EWP-GG beads with a 50.28% immobilization efficiency. The immobilized β-gal (iβ-gal) acquired an escalated thermal stability as compared to its free analogue, and this was proven from the escalations recorded in the iβ-gal half-lives, D-values, activation energy of thermal denaturation, enthalpies, and Gibbs free energies. The proposed biocatalyst exhibited superior operational stability where 89.47 ± 1.34% of the iβ-gal preliminary activity was retained throughout its 24th reusability cycle. The storage stability of the GA-EWP-GG iβ-gal was also superior and 87.64 ± 1.86% of the inceptive iβ-gal activity was retained after 63 days of storage. The biocatalyst efficiently hydrolyzed the whey permeate lactose for five consecutive cycles.
中文翻译:
机械稳定的基于蛋清蛋白的β-D-半乳糖苷酶固定载体:热力学及其在乳清乳糖水解中的应用
β-D-半乳糖苷酶(β-gal)是食品工业中的关键酶,已被固定在基于蛋清蛋白(EWP)的共价固定载体上,机械稳定性不断提高。在加入机械稳定的钙胶凝结冷胶(GG)珠粒后,获得了这种逐步提高的机械稳定性。EWP在吉兰糖胶(GG)珠周围建立了涂层,然后用戊二醛(GA)加工EWP-GG珠。优化了GA-EWP-GG珠的制备工艺,据披露,最佳EWP pH,EWP浓度和GA浓度分别为2-4、7%(w / w)和20-25%(v/ v)。将β-Gal固定在GA-EWP-GG磁珠上,固定效率为50.28%。固定化的β-gal(iβ-gal)与游离的类似物相比具有更高的热稳定性,这可以通过记录在iβ-gal半衰期,D值,热变性活化能,焓中的证明得到证明。和吉布斯自由能。所提出的生物催化剂表现出优异的操作稳定性,其中在其第24个可重复使用周期中保留了89.47±1.34%的iβ-gal初步活性。GA-EWP-GGiβ-gal的储存稳定性也优异,并且在储存63天后保留了87.64±1.86%的iβ-gal活性。生物催化剂连续五个周期有效地水解了乳清渗透乳糖。