The glucose isomerase from Streptomyces olivaceoviridis E-86 was purified by chromatographic procedures, showing one single protein band in the SDS-PAGE. The enzyme had high acid stability, and there was no loss in enzyme activity at pH 5.0 after incubation at 60 degrees C for 30 hr. The enzyme had sufficients activity at 60 degrees C, pH 5.5, (which is the reaction condition for a single-step process with a glucoamylase from A. niger), and at 58 degrees C, pH 6.0, (condition with a glucoamylase from R. niveus). By using this acid-stable glucose isomerase, a single-step process to produce high-fructose corn sweetener (HFCS) from liquefied starch was formed without any reductant or other reagents for enzyme stabilization. The HFCS produced was about fifty percent fructose and less than 1.5% unknown oligosaccharides.
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http://dx.doi.org/10.1271/bbb.64.940 | DOI Listing |
Biophys Chem
December 2024
School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266500, China.
Glucose isomerase is generally used in the industrial production of high-fructose corn syrup, and a heat- and acid-resistant glucose isomerase is preferred. However, most glucose isomerases exhibit low activity or inactivation at low pH. In this study, we demonstrated that two combination mutants formed by introducing positive and negative charges near the active site and on the surface of the enzyme demonstrated a successful reduction in the optimal pH and increase in the specific activity of glucose isomerase from Thermotoga maritima (TMGI).
View Article and Find Full Text PDFBioresour Technol
December 2024
Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea. Electronic address:
Lignocellulosic biomass is a promising renewable feedstock for biodegradable plastics like polyhydroxyalkanoates (PHAs). Cupriavidus necator, a versatile microbial host that synthesizes poly(3-hydroxybutyrate) (PHB), the most abundant type of PHA, has been studied to expand its carbon source utilization. Since C.
View Article and Find Full Text PDFACS Synth Biol
January 2025
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
targeted mutagenesis technologies are the basis for the continuous directed evolution of specific proteins. Here, an efficient mutagenesis system (CgMutaT7) for continuous evolution of the targeted gene in was developed. First, cytosine deaminase and uracil-DNA glycosylase inhibitor were sequentially fused to T7 RNA polymerase using flexible linkers to build the CgMutaT7 system, which introduces mutations in targeted regions controlled by the T7 promoter.
View Article and Find Full Text PDFMicrob Cell Fact
December 2024
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
World J Microbiol Biotechnol
November 2024
School of Pharmaceutical Sciences and Food Engineering, Liaocheng University, Liaocheng, China.
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