Most of the reported bioprocesses carried out by the methylotrophic yeast have been performed at laboratory scale using high power inputs and pure oxygen, such conditions are not feasible for industrial large-scale processes. In this study, volumetric mass transfer (ka) and volumetric gassed power input (Pg/V) were evaluated within values attainable in large-scale production as scale-up criteria for recombinant dextranase production by Mut strain. Cultures were oxygen limited when the volumetric gassed power supply was limited to 2 kW m. Specific growth rate, and then dextranase production, increased as ka and Pg/V did. Meanwhile, specific production and methanol consumption rates were constant, due to the limited methanol condition also achieved at 2 L bioprocesses. The specific dextranase production rate was two times higher than the values previously reported for a Mut strain. After a scale-up process, at constant ka, the specific growth rate was kept at 30 L bioprocess, whereas dextranase production decreased, due to the effect of methanol accumulation. Results obtained at 30 L bioprocesses suggest that even under oxygen-limited conditions, methanol saturated conditions are not adequate to express dextranase with the promoter alcohol oxidase. Bioprocesses developed within feasible and scalable operational conditions are of high interest for the commercial production of recombinant proteins from .
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http://dx.doi.org/10.1080/10826068.2019.1591992 | DOI Listing |
Sheng Wu Gong Cheng Xue Bao
September 2024
School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, Anhui, China.
Dextranase is an enzyme that specifically hydrolyzes the α-1, 6 glucoside bond. In order to improve the activity of dextranase from KQ11, site-directed mutagenesis was used to modify the amino acids involved in the "tunnel-like binding site". A saturating mutation at position 507 was carried out on this basis.
View Article and Find Full Text PDFInt J Biol Macromol
October 2024
College of Food and Biological Engineering, Hefei University of Technology, Hefei, China. Electronic address:
Based on the principle of cascade reaction, a fusion enzyme of dextransucrase and dextranase was designed without linker to catalyze the production of oligo-dextran with homogeneous molecular weight from sucrose in one catalytic step. Due to the different effects of temperature on the two components of the fusion enzyme, temperature served as the "toggle switch" for the catalytic efficiency of the two-level fusion enzyme, regulating the catalytic products of the fusion enzyme. Under optimal conditions, the fusion enzyme efficiently utilized 100 % of the sucrose, and the yield of oligo-dextran with a homogeneous molecular weight reached 70 %.
View Article and Find Full Text PDFFront Biosci (Elite Ed)
June 2024
Biomedical Sciences Research Institute, Ulster University, BT52 1SA Coleraine, UK.
Dextran is an exopolysaccharide synthesized in reactions catalyzed by enzymes obtained from microbial agents of specific species and strains. Products of dextran polysaccharides with different molecular weights are suitable for diverse pharmaceutical and clinical uses. Dextran solutions have multiple characteristics, including viscosity, solubility, rheological, and thermal properties; hence, dextran has been studied for its commercial applications in several sectors.
View Article and Find Full Text PDFWorld J Microbiol Biotechnol
May 2024
São Carlos Institute of Physics, University of São Paulo, Avenida Trabalhador São-carlense, 400, Parque Arnold Schimidt, São Carlos, SP, 13566-590, Brazil.
Cariogenic biofilms have a matrix rich in exopolysaccharides (EPS), mutans and dextrans, that contribute to caries development. Although several physical and chemical treatments can be employed to remove oral biofilms, those are only partly efficient and use of biofilm-degrading enzymes represents an exciting opportunity to improve the performance of oral hygiene products. In the present study, a member of a glycosyl hydrolase family 66 from Flavobacterium johnsoniae (FjGH66) was heterologously expressed and biochemically characterized.
View Article and Find Full Text PDFWorld J Microbiol Biotechnol
February 2024
Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas Margarita Salas (CIB, CSIC), 28040, Madrid, Spain.
Six lactic acid bacteria (LAB) isolated from Algerian sheep's milk, traditional butter, date palm sap and barley, which produce dextran, mannitol, oligosaccharides and vitamin B have been characterized. They were identified as Leuconostoc mesenteroides (A4X, Z36P, B12 and O9) and Liquorilactobacillus mali (BR201 and FR123). Their exopolysaccharides synthesized from sucrose by dextransucrase (Dsr) were characterized as dextrans with (1,6)-D-glucopyranose units in the main backbone and branched at positions O-4, O-2 and/or O-3, with D-glucopyranose units in the side chain.
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