Mycology Department, Federal University of Pernambuco, Cidade Universitária, Recife 50670-420, Pernambuco, Brazil.
Molecules. 2013 Jan 28;18(2):1660-71. doi: 10.3390/molecules18021660.
Polygalacturonases (PG) are pectinolytic enzymes that have technological, functional and biological applications in food processing, fruit ripening and plant-fungus interactions, respectively. In the present, a microtitre plate methodology was used for rapid screening of 61 isolates of fungi from Aspergillus section Nigri to assess production of endo- and exo-PG. Studies of scale-up were carried out in a fixed bed reactor operated under different parameters using the best producer strain immobilised in orange peels. Four experiments were conducted under the following conditions: the immobilised cells without aeration; immobilised cells with aeration; immobilised cells with aeration and added pectin; and free cells with aeration. The fermentation was performed for 168 h with removal of sample every 24 h. Aspergillus niger strain URM 5162 showed the highest PG production. The results obtained indicated that the maximum endo- and exo-PG activities (1.18 U · mL-1 and 4.11 U · mL-1, respectively) were obtained when the reactor was operating without aeration. The microtitre plate method is a simple way to screen fungal isolates for PG activity detection. The fixed bed reactor with orange peel support and using A. niger URM 5162 is a promising process for PG production at the industrial level.
聚半乳糖醛酸酶（PG）是果胶水解酶，分别在食品加工、果实成熟和植物-真菌相互作用中具有技术、功能和生物学应用。在本研究中，使用微量滴定板方法快速筛选来自曲霉属 Nigri 组的 61 个真菌分离物，以评估内切和外切 PG 的生产。使用在橙皮中固定化的最佳生产菌株，在固定床反应器中进行放大研究，以不同参数进行操作。进行了四项实验，条件如下：不充气固定化细胞；充气固定化细胞；充气固定化细胞并添加果胶；充气游离细胞。发酵进行了 168 小时，每 24 小时取出一次样品。黑曲霉菌株 URM 5162 表现出最高的 PG 产量。结果表明，当反应器不充气时，获得了最高的内切和外切 PG 活性（分别为 1.18 U·mL-1 和 4.11 U·mL-1）。微量滴定板法是一种用于筛选真菌分离物以检测 PG 活性的简单方法。使用橙皮作为载体的固定床反应器和黑曲霉 URM 5162 是在工业规模上生产 PG 的有前途的工艺。
