1. A fragment of the β-glucosidase gene from the rumen fungus Neocallimastix patriciarum J11 encodes a recombinant protein that exhibits activities in β-glucosidase and β-glucanase.
- Author
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Liu JC, Cheng HL, Lai YH, Hu CY, and Chen YC
- Subjects
- Animals, Rumen microbiology, Cloning, Molecular, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, Escherichia coli genetics, Escherichia coli metabolism, Fungal Proteins genetics, Fungal Proteins metabolism, beta-Glucans metabolism, Ethanol metabolism, Lignin metabolism, beta-Glucosidase genetics, beta-Glucosidase metabolism, Recombinant Proteins metabolism, Recombinant Proteins genetics, Neocallimastix genetics, Neocallimastix metabolism, Neocallimastix enzymology
- Abstract
Lignocellulose, the most abundant organic waste on Earth, is of economic value because it can be converted into biofuels like ethanol by enzymes such as β-glucosidase. This study involved cloning a β-glucosidase gene named JBG from the rumen fungus Neocallimastix patriciarum J11. When expressed recombinantly in Escherichia coli, the rJBG enzyme exhibited significant activity, hydrolyzing 4-nitrophenyl-β-d-glucopyranoside and cellobiose to release glucose. Surprisingly, the rJBG enzyme also showed hydrolytic activity against β-glucan, breaking it down into glucose, indicating that the rJBG enzyme possesses both β-glucosidase and β-glucanase activities, a characteristic rarely found in β-glucosidases. When the JBG gene was expressed in Saccharomyces cerevisiae and the transformants were inoculated into a medium containing β-glucan as the sole carbon source, the ethanol concentration in the culture medium increased from 0.17 g/L on the first day to 0.77 g/L on the third day, reaching 1.3 g/L on the fifth day, whereas no ethanol was detected in the yeast transformants containing the recombinant plasmid pYES-Sur under the same conditions. These results demonstrate that yeast transformants carrying the JBG gene can directly saccharify β-glucan and ferment it to produce ethanol. This gene, with its dual β-glucosidase and β-glucanase activities, simplifies and reduces the cost of the typical process of converting lignocellulose into bioethanol using enzymes and yeast., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)
- Published
- 2024
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