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Characterization of l-Arabinose Isomerase from Klebsiella pneumoniae and Its Application in the Production of d-Tagatose from d-Galactose
| Content Provider | MDPI |
|---|---|
| Author | Shin, Kyung-Chul Seo, Min-Ju Kim, Sang Jin Kim, Yeong-Su Park, Chang-Su |
| Copyright Year | 2022 |
| Description | D-Tagatose, a functional sweetener, is converted from d-galactose by l-arabinose isomerase, which catalyzes the conversion of l-arabinose to l-ribulose. In this study, the araA gene encoding l-arabinose isomerase from Klebsiella pneumoniae was cloned and expressed in Escherichia coli, and the expressed enzyme was purified and characterized. The purified l-arabinose isomerase, a soluble protein with 11.6-fold purification and a 22% final yield, displayed a specific activity of 1.8 U/mg for d-galactose and existed as a homohexamer of 336 kDa. The enzyme exhibited maximum activity at pH 8.0 and 40 °C in the presence of $Mn^{2+}$ and relative activity for pentoses and hexoses in the order l-arabinose > d-galactose > l-ribulose > d-xylulose > d-xylose > d-tagatose > d-glucose. The thermal stability of recombinant E. coli cells expressing l-arabinose isomerase from K. pneumoniae was higher than that of the enzyme. Thus, the reaction conditions of the recombinant cells were optimized to pH 8.0, 50 °C, and 4 g/L cell concentration using 100 g/L d-galactose with 1 mM $Mn^{2+}$. Under these conditions, 33.5 g/L d-tagatose was produced from d-galactose with 33.5% molar yield and 67 g/L/h productivity. Our findings will help produce d-tagatose using whole-cell reactions, extending its industrial application. |
| Starting Page | 4696 |
| e-ISSN | 20763417 |
| DOI | 10.3390/app12094696 |
| Journal | Applied Sciences |
| Issue Number | 9 |
| Volume Number | 12 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2022-05-07 |
| Access Restriction | Open |
| Subject Keyword | Applied Sciences Biotechnology and Microbiology Klebsiella Pneumoniae L-arabinose Isomerase D-tagatose D-galactose Recombinant Escherichia Coli |
| Content Type | Text |
| Resource Type | Article |
