<b>A Metabolic Study of Biohydrogen-Producing Photosynthetic Bacteria:</b>The Effects on Growth Rates of Rhodobacter capsulatus JP91 Hup- and Rhodopseudomonas palustris when Acetate is replaced by Glucose as the Primary Carbon Source
Bibliographic record
Abstract
The study of photosynthetic purple non-sulfur bacteria (PNSB) is a relatively new and encouraging field of biofuel research. These bacteria metabolize organic acids and, though less efficiently, sugars into hydrogen – a high-energy fuel source. If the efficiency of glucose-to-hydrogen conversion could be increased, many waste products could be directly converted into fuel. This project investigated relative growth performance of strains of PNSB when glucose replaced sodium acetate as the primary carbon source. The potential benefit of increased genetic diversity of mixed cultures was also explored. The growth rates of two bioreactors each containing Rhodobacter capsulatus JP91 Hup- were compared to those of two bioreactors populated with a consortium of PNSB (R. capsulatus JP91 Hup- and two strains of Rhodopseudomonas palustris). The bacterial cultures were grown anaerobically in constant flow photobioreactors. Growth rates were determined by measuring changes in biodensity. There was no significant difference in growth rates between monocultures and mixed cultures. However, the growth rates of bacteria on glucose were generally equal to or greater than those on acetate. This result suggests that further study of metabolic patterns of PNSB presented with various carbon sources may prove useful in exploring the viability of single-stage conversion of waste sugars into biohydrogen fuel. L’étude de bactéries pourpres non sulfureuses (BPNS) est relativement nouvelle et un domaine prometteur à l’égard de la recherche sur les biocarburants. Ces bactéries métabolisent les acides organiques et, bien que de façon moins efficaces, métabolisent aussi les sucres à l’hydrogène – une source de carburant à haute énergie. Si l’efficacité de la conversion de glucose à hydrogène pouvait être augmentée, de nombreux déchets organiques pourraient être directement convertis en carburant. Ce projet a étudié le rendement de croissance relative des souches de BPNS lorsque le glucose fut remplacé par de l'acétate de sodium comme source de carbone primaire. L'avantage potentiel de l'augmentation de la diversité génétique de cultures mixtes a également été examiné. Le taux de croissance des deux bioréacteurs contenant chacun Rhodobacter capsulatus JP91 Hup- ont été comparées à deux bioréacteurs peuplés avec un consortium de BPNS (R. capsulatus JP91 Hup-et deux souches de Rhodopseudomonas palustris). Les cultures bactériennes ont été cultivées anaérobiquement dans des photobioréacteurs à débit constant. Les taux de croissance ont été déterminés en mesurant la variation de biodensité. Il n'y avait pas de différence significative dans le taux de croissance entre les monocultures et les cultures mixtes. Cependant, le taux de croissance avec le glucose était généralement égale ou supérieure comparé à l’acétate. Ce résultat suggère que d'autres études du profils métaboliques de PNSB avec diverses sources de carbones peuvent s’avérer utiles dans l'exploration de la viabilité de la conversion à étape simple de déchets organiques détenant du sucre en biohydrogène.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".