Autor: |
Paulo César Silva, Javier A. Ceja-Navarro, Flávio Azevedo, Ulas Karaoz, Eoin L. Brodie, Björn Johansson |
Jazyk: |
angličtina |
Rok vydání: |
2021 |
Předmět: |
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Zdroj: |
Scientific Reports, Vol 11, Iss 1, Pp 1-12 (2021) |
Druh dokumentu: |
article |
ISSN: |
2045-2322 |
DOI: |
10.1038/s41598-021-83937-z |
Popis: |
Abstract Carbohydrate rich substrates such as lignocellulosic hydrolysates remain one of the primary sources of potentially renewable fuel and bulk chemicals. The pentose sugar d-xylose is often present in significant amounts along with hexoses. Saccharomyces cerevisiae can acquire the ability to metabolize d-xylose through expression of heterologous d-xylose isomerase (XI). This enzyme is notoriously difficult to express in S. cerevisiae and only fourteen XIs have been reported to be active so far. We cloned a new d-xylose isomerase derived from microorganisms in the gut of the wood-feeding beetle Odontotaenius disjunctus. Although somewhat homologous to the XI from Piromyces sp. E2, the new gene was identified as bacterial in origin and the host as a Parabacteroides sp. Expression of the new XI in S. cerevisiae resulted in faster aerobic growth than the XI from Piromyces on d-xylose media. The d-xylose isomerization rate conferred by the new XI was also 72% higher, while absolute xylitol production was identical in both strains. Interestingly, increasing concentrations of xylitol (up to 8 g L−1) appeared not to inhibit d-xylose consumption. The newly described XI displayed 2.6 times higher specific activity, 37% lower KM for d-xylose, and exhibited higher activity over a broader temperature range, retaining 51% of maximal activity at 30 °C compared with only 29% activity for the Piromyces XI. |
Databáze: |
Directory of Open Access Journals |
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