Biobutanol production from cellulosic and sugar-based feedstock from the corn plant
Bibliographic record
Abstract
In this thesis, biobutanol production by biological fermentation was investigated from the corn plant, integrating two approaches. The first one was to utilize corn cobs, a cellulosic-based material. The second, using a new sugar-based material, sugarcorn juice. Utilizing suitable Clostridia strains for each substrate, these approaches converged into a biorefinery concept to produce renewable biofuels in Ontario, Canada. The corn cob pretreatment was carried out by a dilute acid method resulting in temperature as the variable with most significant effect towards glucose liberation. The enzymatic hydrolysis was performed utilizing a very low concentration of an enzymatic stock solution with approximately 44% of hydrolysis conversion. Biobutanol fermentation was pursued utilizing a Clostridium beijerinckii strain and cellulosic biobutanol was produced in a concentration of 4.42 g L-1 at 48h with 97% of reducing sugars utilization.\nDifferent ABE fermentations by Clostridium saccharobutylicum ATTC BAA-117 using glucose, fructose, sucrose, and a mix of them, resulted in butanol production as high as 12-14 g L-1. For the first time, sugarcorn juices from Canadian corn hybrids, were characterized and proven as a suitable medium for biobutanol production. Variation in sugar composition of sugarcorn juices across different hybrids and growth seasons were observed during this study, from 102 g L-1 to 145 g L-1, with fructose, glucose and sucrose accounting for about 80%.\nClostridium beijerinckii 6422 produced 8.49 g L-1 of butanol over 257h of fermentation utilizing sugarcorn juice as substrate. It had a biphasic fermentation where acids accumulation happened at the beginning of fermentation. Interestingly, at the end of the fermentation butyric acid was reactivated and the butanol production shifted towards butyric acid production. Clostridium saccharobutylicum produced 11.05 g L-1 of butanol over 227 h of fermentation utilizing sugarcorn juice as substrate. Both strains could utilize sucrose, fructose and glucose concomitantly. There is enough evidence to agree that Clostridium saccharobutylicum has a PTS-sucrose system which allows the cell to transport sucrose inside the cell.\nThe proposed Canadian sugarcorn (CANSUG) biorefinery can commercially generate biofuels and biochemicals while limiting wastes, offer environmental benefits to the energy sector, and strengthen the Canadian bio-economy.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".