Pedrolli D B, Carmona E C
Biochemystry and Microbiology Department Biosciences Institute, São Paulo State University, Unesp, Caixa Postal 199, 13506-900, Brazil.
Prikl Biokhim Mikrobiol. 2009 Nov-Dec;45(6):677-83.
The aim of this study was to investigate some of the factors affecting pectin lyase (PL) production by an Aspergillus giganteus strain, and to characterize this pectinolytic activity excreted into the medium. The highest activities were obtained with orange waste, citrus pectin and galacturonic acid as carbon sources. The highest activity, using citrus pectin as carbon source, was obtained in 11-day-old standing cultures, but the highest specific activity was obtained in 6.5-day-old shaken cultures, at pH 6.5 and 35 degrees C. Using orange waste as carbon source, the highest activity was observed in 8-day-old standing cultures, at pH 7.0 and 30 degrees C. Optimal assay conditions were pH 8.5-9.0 and 50 degrees C. The PL activity showed thermal stability, with half-lives of 30 and 27 min when incubated at 45 and 50 degrees C, respectively. High stability was observed at room temperature from pH 6.0 to 10.0; more than 85% of enzyme activity was preserved in this pH range. Under optimum conditions, the highest pectin lyase activity in the medium was 470 U/ml, with orange waste as carbon source.
本研究的目的是调查影响巨大曲霉产生果胶裂解酶（PL）的一些因素，并对分泌到培养基中的这种果胶分解活性进行表征。以橙皮废料、柑橘果胶和半乳糖醛酸作为碳源时，可获得最高活性。以柑橘果胶作为碳源时，在11日龄静置培养物中可获得最高活性，但在pH 6.5和35℃条件下，6.5日龄振荡培养物中可获得最高比活性。以橙皮废料作为碳源时，在pH 7.0和30℃条件下，8日龄静置培养物中可观察到最高活性。最佳测定条件为pH 8.5 - 9.0和50℃。PL活性具有热稳定性，在45℃和50℃孵育时，半衰期分别为30分钟和27分钟。在室温下，pH值在6.0至10.0之间时观察到高稳定性；在此pH范围内，超过85%的酶活性得以保留。在最佳条件下，以橙皮废料作为碳源时，培养基中最高果胶裂解酶活性为470 U/ml。
