de Oliveira Rodrigo Lira, Dos Santos Vinícius Luís Vilela, da Silva Marcos Fellipe, Porto Tatiana Souza
Northeast Biotechnology Network/RENORBIO, Federal Rural University of Pernambuco (UFRPE), Dom Manoel de Medeiros, Dois Irmãos, 52171-900 Recife, PE, Brazil.
Academic Unit of Garanhuns/UAG, Federal Rural University of Pernambuco (UFRPE), Av. Bom Pastor, Boa Vista, 55296-901 Garanhuns, PE, Brazil.
Food Res Int. 2020 Nov;137:109730. doi: 10.1016/j.foodres.2020.109730. Epub 2020 Sep 21.
β-fructofuranosidase (FFase) from Aspergillus tamarii URM4634 was immobilized covalently in chitosan beads. It was characterized biochemically, studied in terms of kinetic and thermodynamic parameters, and applied on conversion of sucrose for invert sugar production in a packed bed reactor (PBR). The optimum reactional conditions were determined and obtained at pH 5.0 and 60 °C. FFase was thermostable at 50-55°C. At 50°C, the enzyme shows longer half-life (t) (594.13 min) and a higher D-value (1,973.64 min). This indicates that immobilized FFase was stable at temperature commonly used in invert sugar production. The following thermodynamic parameters were obtained: activation energy (E* = 301.57 kJ mol), enthalpy (298.76 ≤ ΔH* ≤ 298.89 kJ mol), entropy (579.88 ≤ ΔS* ≤ 589.27 J K mol) and Gibbs free energy (100.29 ≤ ΔG* ≤ 108.47 kJ mol). The high E*, ΔH* and ΔG* values confirmed FFase thermostability. The high and positive values for ΔS* indicate an increase in disorder due opening of the enzyme structure. The sucrose hydrolysis in PBR showed a maximum invert sugar yield (96.0%) at 15 min of operation. The hydrolysis process remained efficient up to 100 min (70.22%). The results obtained in the present study provide a good indication that immobilized FFase on chitosan beads in PBR is efficient to invert sugar production for food industry.
来自黑曲霉URM4634的β-呋喃果糖苷酶（FFase）被共价固定在壳聚糖珠中。对其进行了生化表征，研究了动力学和热力学参数，并应用于填充床反应器（PBR）中蔗糖转化为转化糖的生产。确定并获得了在pH 5.0和60°C下的最佳反应条件。FFase在50 - 55°C下具有热稳定性。在50°C时，该酶显示出更长的半衰期（t）（594.13分钟）和更高的D值（1,973.64分钟）。这表明固定化的FFase在转化糖生产常用的温度下是稳定的。获得了以下热力学参数：活化能（E* = 301.57 kJ mol）、焓（298.76≤ΔH*≤298.89 kJ mol）、熵（579.88≤ΔS*≤589.27 J K mol）和吉布斯自由能（100.29≤ΔG*≤108.47 kJ mol）。高E*、ΔH和ΔG值证实了FFase的热稳定性。ΔS*的高正值表明由于酶结构的打开导致无序度增加。PBR中的蔗糖水解在运行15分钟时显示出最大转化糖产率（96.0%）。水解过程在100分钟内（70.22%）仍保持高效。本研究获得的结果充分表明，PBR中固定在壳聚糖珠上的FFase对于食品工业中转化糖的生产是有效的。
