Enhancement of Lactobionic Acid Productivity by Homologous Expression of Quinoprotein Glucose Dehydrogenase in Pseudomonas taetrolens

• Published in: Journal of agricultural and food chemistry 2020-11, Vol.68 (44), p.12336-12344
• Main Authors: Oh, Yu-Ri, Jang, Young-Ah, Lee, Seung Soo, Kim, Jang-Ho, Hong, Soon Ho, Han, Jeong Jun, Eom, Gyeong Tae
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biotechnology and Biological Transformations; Disaccharides - biosynthesis; Gene Expression; Glucose Dehydrogenases - genetics; Glucose Dehydrogenases - metabolism; Lactose - metabolism; Metabolic Engineering; Pseudomonas - genetics; Pseudomonas - metabolism
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.0c04246

This is the first study on improving lactobionic acid (LBA) production capacity in Pseudomonas taetrolens by genetic engineering. First, quinoprotein glucose dehydrogenase (GDH) was identified as the lactose-oxidizing enzyme of P. taetrolens. Of the two types of GDH genes in P. taetrolens, membrane-bound (GDH1) and soluble (GDH2), only GDH1 showed lactose-oxidizing activity. Next, the genetic tool system for P. taetrolens was developed based on the pDSK519 plasmid for the first time, and GDH1 gene was homologously expressed in P. taetrolens. Recombinant expression of the GDH1 gene enhanced intracellular lactose-oxidizing activity and LBA production of P. taetrolens in flask culture. In batch fermentation of the recombinant P. taetrolens using a 5 L bioreactor, the LBA productivity of the recombinant P. taetrolens was approximately 17% higher (8.70 g/(L h)) than that of the wild type (7.41 g/(L h)). The LBA productivity in this study is the highest ever reported using bacteria as production strains for LBA.