| title: | Growth at low growth rates. Theory and practice |
|---|---|
| reg no: | ETF5160 |
| project type: | Estonian Science Foundation research grant |
| subject: |
1.7. Organic Chemistry and Biochemistry 2.7. Biotechnology, Food and Drink Technology |
| status: | completed |
| institution: | Tallinn Technical University |
| head of project: | Toomas Paalme |
| duration: | 01.01.2002 - 31.12.2005 |
| description: | Microbes often grow in nature and bioreactors at very low growth rates. However, the physiological consequences at low growth rates have not been explored as completely as at faster growth rates. Nutrient flux to (and through) the cell surface and non-growth-dependent energy consumption (maintenance) are important considerations under these conditions. In the current work 1) the role of trehalose and glycogen accumulation during growth of yeast at low growth rates and 2) the growth of mesophilic lactobacilli in the sugar-free environment will be studied. It will be studied whether the trehalose accumulates due to a) low growth rates signal about possible transition into resting state or b) trehalose stores are required to support the effective growth at low growth rates. The aim of the study is to elucidate the control algorithms of the trehalose accumulation/mobilization cycle. To visualize the process in the individual cells the study will be carried out by inducing the long and short period auto-oscillations and alternatively by unique 13C-labelling technique in combination with the multi-steady-state stoichiometric growth model of label movement. The synchronization of trehalose accumulation to improve the quality of dry active yeasts will be studied as well. We would like to collect the evidence that the energy accumulation/mobilization cycle (metabolic circulation) is a universal principle of biological cell design to ensure the effective growth of individual cells. The energetics of mesophilic lactobacilli, important in the process of ripening of cheese will be investigated. The NSLAB (non-starter lactic acid bacteria) grow effectively in conditions of slow release of growth substrates from casein matrix. The energy sources for bacterial growth are still not clearly identified, and growth dynamics with apparent growth rate 0.01 h-1 not understood. The question, which are the specific mechanisms of NSLAB supporting growth at slow growth rates, will be asked. |
| project group | ||||
|---|---|---|---|---|
| no | name | institution | position | |
| 1. | Kaarel Adamberg | TTU, ICPB | Ph.D student | |
| 2. | Kaja Kasemets | TTU, ICPB | Ph.D student | |
| 3. | Signe Kask | TTU. ICPB | Ph.D student | |
| 4. | Tiiu-Maie Laht | ICPB | Res.Sci | |
| 5. | Ildar Nisamedtinov | "Salutaguse" | R&D | |
| 6. | Toomas Paalme | Tallinn Technical University | Prof. | |