Graduate Program in Biotechnology, Federal University of Alfenas, 37130-001 Alfenas, MG, Brazil; Institute of Chemistry, Federal University of Alfenas, 37130-001 Alfenas, MG, Brazil.
Institute of Chemistry, Federal University of Alfenas, 37130-001 Alfenas, MG, Brazil.
Int J Biol Macromol. 2020 Nov 15;163:550-561. doi: 10.1016/j.ijbiomac.2020.07.021. Epub 2020 Jul 6.
In this study, a new mixed heterofunctional support (Chit-GA-Gly) has been prepared by sequential activation of chitosan hydrogel (Chit) with glutaraldehyde (GA) and further functionalization with glycine (Gly). The immobilization of the lipase from Thermomyces lanuginosus (TLL) on this support was compared with that on GA-activated Chit hydrogel (Chit-GA). The supports have been characterized by FT-IR, zeta potential and TG analyses. A similar maximum lipase loading of 53-55 mg per gram of support has been obtained for both supports. Both biocatalysts retained ≈40% of their initial activity after 48 h of incubation at 50 °C in heptane, toluene or iso-octane. The immobilization of TLL on Chit-GA proceeded via preferential covalent attachment (95%) and a combined ion exchange (cationic and anionic) and hydrophobic adsorption was observed using Chit-GA-Gly. TLL immobilized on Chit-GA-Gly was ≈4-times more active than when immobilized on Chit-GA in both olive oil emulsion hydrolysis and alkyl palmitate synthesis via esterification. Isoamyl palmitate synthesis in iso-octane at 50 °C using this new biocatalyst gave a maximum acid conversion of 85% after 90 min of reaction. After nine consecutive esterification batches, the biocatalyst retained around 40% of its initial activity.
在这项研究中，通过顺序激活壳聚糖水凝胶（Chit）与戊二醛（GA），并进一步与甘氨酸（Gly）功能化，制备了一种新的混合杂化功能化载体（Chit-GA-Gly）。将脂肪酶从Thermomyces lanuginosus（TLL）固定在该载体上的情况与固定在 GA 激活的壳聚糖水凝胶（Chit-GA）上的情况进行了比较。通过 FT-IR、ζ电位和 TG 分析对载体进行了表征。两种载体的最大脂肪酶负载量均为 53-55mg/g。在庚烷、甲苯或异辛烷中于 50°C 孵育 48 小时后，两种生物催化剂的初始活性保留率均约为 40%。TLL 在 Chit-GA 上的固定通过优先共价附着（95%）进行，而在 Chit-GA-Gly 上则观察到离子交换（阳离子和阴离子）和疏水吸附的组合。TLL 固定在 Chit-GA-Gly 上时，在橄榄油乳液水解和通过酯化进行的烷基棕榈酸酯合成中的活性比固定在 Chit-GA 上时分别高出约 4 倍。使用这种新的生物催化剂在 50°C 的异辛烷中合成异戊酸棕榈酸酯，在 90 分钟的反应后可获得最大酸转化率为 85%。在连续进行了九个酯化批次后，生物催化剂保留了其初始活性的约 40%。
