High yield of mannosylglycerate production by upshock fermentation and bacterial milking of trehalose-deficient mutant <Emphasis Type="Italic">Thermus thermophilus</Emphasis> RQ-1 |
| |
Authors: | K Egorova T Grudieva C Morinez J Kube H Santos M S da Costa G Antranikian |
| |
Institution: | (1) Institute of Technical Microbiology, Hamburg University of Technology, Kasernenstr 12, 21073 Hamburg, Germany;(2) Institute of Bioprocess and Biosystem Engineering, Hamburg University of Technology, Denickestr. 15, 21073 Hamburg, Germany;(3) Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6, Apartado 127, 2780-156 Oeiras, Portugal;(4) Laboratorio de Microbiologia, Departamento de Zoologia, Universidade de Coimbra, 3004-517 Coimbra, Portugal |
| |
Abstract: | A production process, using upshock fermentation and osmotic downshock, for the effective production/excretion of mannosylglycerate
(MG) by the trehalose-deficient mutant of the strain Thermus thermophilus RQ-1 has been developed. In the first phase of fed-batch fermentation, the knockout mutant was grown at 70°C on a NaCl-free
medium. After the culture reached the end of the exponential growth phase, upshift in temperature and NaCl concentration was
applied. The temperature was increased to 77°C, and NaCl was added up to 3.0% and kept constant during the second phase of
fermentation. Although this shift in cultivation parameters caused a dramatic drop of cell density, a significant improvement
in accumulation of MG up to 0.64 μmol/mg protein compared to batch fermentations (0.31 μmol/mg protein) was achieved. A total
yield of 4.6 g MG/l of fermentation broth was obtained in the dialysis bioreactor with a productivity of 0.29 g MG l−1 h−1. The solute was released from the harvested biomass by osmotic downshock using demineralized water at 70°C. More than 90%
of the intracellularly accumulated solute was recovered from the water fraction. The process was very efficient, as hyperosmotic
shock, release of the solute, and reiterative fed-batch fermentation could be repeated at least four times. |
| |
Keywords: | Mannosylglycerate Fermentation Thermus |
本文献已被 PubMed SpringerLink 等数据库收录! |
|