| 1. |
- Ishola, Mofoluwake M., et al.
(author)
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Effect of high solids loading on bacterial contamination in lignocellulosic ethanol production
- 2013
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In: BioResources. - : North Carolina State University. - 1930-2126. ; 8:3, s. 4429-4439
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Journal article (peer-reviewed)abstract
- Contamination by lactic acid-producing bacteria is frequently a major challenge in ethanol processes. In this work, high solids loading was used both to keep bacterial infection under control in simultaneous saccharification and fermentation (SSF) of lignocellulosic biomass and to increase the ethanol productivity of the process. With no sterilization of the substrates, lactic acid bacteria contaminated the fermentation process with 8 and 10% suspended solids (SS) substrates, consumed both pentoses and hexoses, and produced lactic acid. However, a high solids loading of 12% SS prevented lactic acid formation, which resulted in higher ethanol yield during the SSF process. This high SS resulted in an ethanol concentration of 47.2 g/L, which satisfies the requirement for industrial lignocellulosic ethanol production.
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| 2. |
- Isroi, Isroi, 1974, et al.
(author)
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Structural Changes of Oil Palm Empty Fruit Bunch (OPEFB) after Fungal and Phosphoric Acid Pretreatment
- 2012
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In: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049 .- 1431-5157. ; 17:12, s. 14995-15012
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Journal article (peer-reviewed)abstract
- Oil palm empty fruit bunch (OPEFB) was pretreated using white-rot fungus Pleurotus floridanus, phosphoric acid or their combination, and the results were evaluated based on the biomass components, and its structural and morphological changes. The carbohydrate losses after fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 7.89%, 35.65%, and 33.77%, respectively. The pretreatments changed the hydrogen bonds of cellulose and linkages between lignin and carbohydrate, which is associated with crystallinity of cellulose of OPEFB. Lateral Order Index (LOI) of OPEFB with no pretreatment, with fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 2.77, 1.42, 0.67, and 0.60, respectively. Phosphoric acid pretreatment showed morphological changes of OPEFB, indicated by the damage of fibre structure into smaller particle size. The fungal-, phosphoric acid-, and fungal followed by phosphoric acid pretreatments have improved the digestibility of OPEFB's cellulose by 4, 6.3, and 7.4 folds, respectively.
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| 3. |
- Akintunde, Moyinoluwa, et al.
(author)
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Bacterial Cellulose Production from agricultural Residues by two Komagataeibacter sp. Strains
- 2022
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In: Bioengineered. - : Informa UK Limited. - 2165-5979 .- 2165-5987. ; 13:4, s. 10010-10025
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Journal article (peer-reviewed)abstract
- Agricultural residues are constantly increasing with increased farming processes, and improper disposal is detrimental to the environment. Majority of these waste residues are rich in lignocellulose, which makes them suitable substrate for bacterial fermentation in the production of valueadded products. In this study, bacterial cellulose (BC), a purer and better form of cellulose, was produced by two Komagataeibacter sp. isolated from rotten banana and kombucha drink using corncob (CC) and sugarcane bagasse (SCB) enzymatic hydrolyzate, under different fermentation conditions, that is, static, continuous, and intermittent agitation. The physicochemical and mechanical properties of the BC films were then investigated by Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetry analysis, Field Emission Scanning Electron Microscopy (FESEM), and Dynamic mechanical analysis. Agitation gave a higher BC yield, with Komagataeibacter sp. CCUG73629 producing BC from CC with a dry weight of 1.6 g/L and 1.4 g/L under continuous and intermittent agitation, respectively, compared with that of 0.9 g/L in HS medium. While BC yield of dry weight up to 1.2 g/L was obtained from SCB by Komagataeibacter sp. CCUG73630 under continuous agitation compared to that of 0.3 g/L in HS medium. FTIR analysis showed BC bands associated with cellulose I, with high thermal stability. The FE-SEM analysis showed that BC fibers were highly ordered and densely packed. Although the BC produced by both strains showed similar physicochemical and morphological properties, the BC produced by the Komagataeibacter sp. CCUG73630 in CC under intermittent agitation had the best modulus of elasticity, 10.8 GPa and tensile strength, 70.9 MPa. [GRAPHICS]
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| 4. |
- Aremu, Mujidat Omolara, et al.
(author)
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Polyhydroxyalkanoates (Phas) production from volatile fatty acids (vfas) from organic wastes by pseudomonas oleovorans
- 2021
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In: Fermentation. - : MDPI. - 2311-5637. ; 7:4
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Journal article (peer-reviewed)abstract
- This study aimed to investigate the production of polyhydroxyalkanoates (PHAs), a biodegradable polymer from organic wastes by Pseudomonas oleovorans. Volatile fatty acids (VFAs) from acidogenic fermentations of chicken manure (VFAs-CM) and potato peels (VFAs-PP), rich in organic matter majorly acetic (49.9%), butyric (15%) and propionic acids (11.1%) were utilized as substrates for microbial processes. During 72 h of cultivations, samples were withdrawn at intervals and analyzed for cell growth parameters, PHAs accumulation and polymeric properties. The highest biopolymer accumulation (0.39 g PHAs/g DCW) was achieved at 48 h of cultivation from medium containing VFAs-PP as the sole source of carbon. On characterization, the produced biopolymers were shown to be semi-crystalline of carbonyl C=O group. Additionally, thermogravimetric analysis (TGA) showed that the produced biopolymers demonstrated the capability to withstand thermal degradation above prescribed temperatures at which cross-linking isomerization reaction occurs, which is a vital property denoting the thermal stability of biopolymer. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 5. |
- Ishola, Mofoluwake M., et al.
(author)
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Simultaneous saccharification, filtration and fermentation (SSFF) : A novel method for bioethanol production from lignocellulosic biomass
- 2013
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In: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 133, s. 68-73
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Journal article (peer-reviewed)abstract
- Simultaneous saccharification, filtration and fermentation (SSFF) was developed for lignocellulosic ethanol production. In SSFF, pretreated lignocellulosic material is enzymatically hydrolyzed in a reactor, while the suspension is continuously pumped through a cross-flow membrane. The retentate goes back to the hydrolysis vessel, while a clear sugar-rich filtrate continuously perfuses through the fermentation vessel before it is pumped back to the hydrolysis vessel. The capacity and life span of the cross-flow filter module was examined for 4 weeks using enzymatically hydrolyzed slurry, initially with 14.4% suspended solids, without clogging or fouling. An ethanol yield of 85.0% of the theoretical yield was obtained in SSFF and a flocculating strain of Saccharomyces cerevisiae was successfully reused for five cultivations of SSFF.
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| 6. |
- Aslanzadeh, Solmaz, et al.
(author)
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An Overview of Existing Individual Unit Operations
- 2014
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In: Biorefineries. - : Elsevier Inc.. - 9780444594983
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Book chapter (peer-reviewed)abstract
- BACKGROUND: Because of its extreme toxicity for microorganisms, the limonene content of citrus wastes (CWs) has been a major obstacle to the conversion of CWs to biofuels. The main objective of this study was to develop a new process for the utilization of CWs that can be economically feasible when the supply of CW is low.RESULTS: Steam explosion pre-treatment was applied to improve the anaerobic digestibility of CWs, resulting in a decrease of initial limonene concentration by 94.3%. A methane potential of 0.537 ± 0.001 m 3 kg -1 VS (volatile solids) was obtained during the following batch digestion of treated CWs, corresponding to an increase of 426% compared with that of the untreated samples. Long-term effects of the treatment were further investigated by a semi-continuous co-digestion process. A methane production of 0.555 ± 0.0159 m 3 CH 4 kg -1 VS day -1 was achieved when treated CWs (corresponding to 30% of the VS load) were co-digested with municipal solid waste.CONCLUSION: The process developed can easily be applied to an existing biogas plant. The equipment cost for this process is estimated to be one million USD when utilizing 10 000 tons CWs year -1. 8.4 L limonene and 107.4 m 3 methane can be produced per ton of fresh citrus wastes in this manner.
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| 7. |
- Ishola, Mofoluwake M., et al.
(author)
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Biofuels in Nigeria : A critical and strategic evaluation
- 2013
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In: Renewable energy. - : Pergamon. - 0960-1481 .- 1879-0682. ; 55, s. 554-560
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Journal article (peer-reviewed)abstract
- Nigeria is among the World’s 10 most important exporters of petroleum, but has several difficulties in its domestic energy situation. Power outages are frequent in the cities and 49% of the population has no access to electricity at all. The use of fossil fuels and firewood causes many environmental problems and the population increase in combination with a growing economy results in unmanageable amounts of waste in the cities. The use of biofuels has the potential to alleviate some of these problems and this review aims at evaluating the situation regarding biofuel production in Nigeria through literature studies and contacts. It was found that in spite of good geographic conditions and high investment in biofuel production, progress has been slow. The Nigerian sugarcane sector does not yet satisfy the domestic demand for sugar, while large-scale sugarcane-based ethanol production seems distant. Ethanol production from cassava would require input of energy and enzymes and would probably be too expensive. Sweet sorghum, which is relatively easy to process into bioethanol, has some advantages in a Nigerian context, being widely cultivated. Biodiesel production runs the risk of becoming controversial if edible crops currently being imported would be used. Jatropha curcas (non-edible) is an interesting crop for biodiesel production but the complete life cycle of this process should be further analyzed. The biofuel concept, which would bring the most immediate benefits, is probably biogas production from waste. It requires no irrigation or input of land and also provides a cleaner environment. Besides it would reduce the widespread use of firewood and produce fertilizer.
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| 8. |
- Ishola, Mofoluwake M, et al.
(author)
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Co-Utilization of Glucose and Xylose for Enhanced Lignocellulosic Ethanol Production with Reverse Membrane Bioreactors.
- 2015
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In: Membranes. - : MDPI AG. - 2077-0375. ; 5:4, s. 844-856
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Journal article (peer-reviewed)abstract
- Integrated permeate channel (IPC) flat sheet membranes were examined for use as a reverse membrane bioreactor (rMBR) for lignocellulosic ethanol production. The fermenting organism, Saccharomyces cerevisiae (T0936), a genetically-modified strain with the ability to ferment xylose, was used inside the rMBR. The rMBR was evaluated for simultaneous glucose and xylose utilization as well as in situ detoxification of furfural and hydroxylmethyl furfural (HMF). The synthetic medium was investigated, after which the pretreated wheat straw was used as a xylose-rich lignocellulosic substrate. The IPC membrane panels were successfully used as the rMBR during the batch fermentations, which lasted for up to eight days without fouling. With the rMBR, complete glucose and xylose utilization, resulting in 86% of the theoretical ethanol yield, was observed with the synthetic medium. Its application with the pretreated wheat straw resulted in complete glucose consumption and 87% xylose utilization; a final ethanol concentration of 30.3 g/L was obtained, which corresponds to 83% of the theoretical yield. Moreover, complete in situ detoxification of furfural and HMF was obtained within 36 h and 60 h, respectively, with the rMBR. The use of the rMBR is a promising technology for large-scale lignocellulosic ethanol production, since it facilitates the co-utilization of glucose and xylose; moreover, the technology also allows the reuse of the yeast for several batches.
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| 9. |
- Ishola, Mofoluwake M., et al.
(author)
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Development and Evaluation of a Novel Method for Lignocellulosic Ethanol Production : Simultaneous Saccharification Filtration and Fermentation (SSFF)
- 2014
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Conference paper (peer-reviewed)abstract
- A novel method of lignocellulosic ethanol production was developed and evaluated, “Simultaneous Saccharification Filtration and Fermentation (SSFF)”. SSFF is an integrated process which combines the advantages of both Separate hydrolysis and fermentation (SHF) and Simultaneous saccharification and fermentation (SSF). The process involves simultaneous enzymatic hydrolysis of lignocellulosic biomass, filtration and fermentation of the filtrate with yeast Saccharomyces cerevisiae as fermenting organism. Different suspended solid (SS) were evaluated to determine what solid concentration can be pumped through the filtration device and the life span of a cross-flow filter module was assessed. Capacity tests were performed on the fermentation unit to determine the uptake capability of the fermenting organism. It was furthermore investigated how long the cells can be successfully reused. It was observed that up to 14% solids concentration could be pumped through the filtration unit. After enzymatic treatment, a slurry with 14.4% initial SS was filtered continuously for 28 days without clogging or fouling. A flocculating yeast strain (CCUG 53310) was able to consume the glucose from the hydrolysis through the filtration effectively and the yeast culture was reused for 5 batches of SSFF. The SSFF cultivations resulted in an ethanol yield of up to 85.0% of the theoretical yield. Our new process of SSFF could potentially be used in lignocellulosic ethanol production.
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| 10. |
- Ishola, Mofoluwake M., et al.
(author)
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Effect of Fungal and Phosphoric acid Pretreatment on Ethanol production from Empty Fruit Bunches (EFB) during Simultaneous Saccharification and Fermentation (SSF).
- 2013
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Conference paper (peer-reviewed)abstract
- Empty fruit bunches (EFB) is a lignocellulosic residue after palm oil extraction and can be a cheap feedstock for lignocellulosic ethanol production. EFB was pretreated with phosphoric acid as a means of chemical pretreatment and white rot fungi Pleurotus floridanus LIPIMC966 as a means of biological pretreatment, both methods were later combined. The pretreated materials were fermented to ethanol with simultaneous saccharification and fermentation (SSF). SSF was performed at temperature of 31°C and a pH of 5.0. Cellulase enzyme Cellic® CTec2, was used for the hydrolysis and yeast Saccharomyces cerevisiae CBS 8066 was used for the fermentation. Hydrolysis alone was also carried out on the EFB so as to measure digestibility with the different pretreatments. Pretreatment with combination of the two methods, phosphoric acid pretreatment and fungal pretreatment improves the digestibility by 7.4, 6.3 and 4.0 folds respectively. During the SSF, phosphoric acid pretreatment gave the highest ethanol yield of 77.2% of the theoretical yield at 48 h, combination of phosphoric and fungal pretreatment gave highest yeild of 76% at 48 h while a yield of 24% was produced as the highest yeild from the fungal pretreated material at 72 h. This study shows that a combination of phosphoric acid and fungal pretreatment could potentially increase the ethanol yield from this lignocellulosic material.
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