Development of rapid bioconversion with integrated recycle technology for ethanol production from extractive ammonia pretreated corn stover

Jin, Mingjie; Liu, Yanping; Sousa, Leonardo da Costa; Dale, Bruce E.; Balan, Venkatesh

doi:10.1002/bit.26302

Cited by 15 publications

(9 citation statements)

References 24 publications

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“…7 Currently they applied this technology to EA-pretreated (extractive-ammonia-pretreated) corn stover, and the enzyme loading was reduced by 30% to 8.4 mg EP/g cellulose while maintaining a 40 g/L ethanol concentration. 13 To our knowledge, the result obtained in this study was the lowest cellulase dosage (3.3 mg EP/g cellulose) that can reach an a Ethanol yield was calculated on the basis of the theoretical ethanol yield produced from the cellulose in DCCR (Zhang and Bao, 2012).…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…9 Partial enzymes reversibly bound to unhydrolyzed solid (UHS) residues could be recycled by removing the liquid hydrolysate and adding fresh substrates for a subsequent batch of hydrolysis. 10,11,13 Cellulase could also be recycled by reusing a small amount of SSF broth, but xylose and lignin accumulation will cause a negative effect on the next round of SSF. 6 Recycling the cellulase present in the stillage requires vacuum distillation conducted at low temperatures (below 55 °C) to avoid denaturing the cellulase activity.…”

Section: ■ Introductionmentioning

confidence: 99%

“…A number of innovative methods were developed to reduce the cost of cellulase to make cellulosic ethanol cost-competitive. − Some of these studies focused on recycling cellulase from three process streams, including the following: (1) the hydrolysate slurry after enzymatic hydrolysis, − (2) the fermentation broth after simultaneous saccharification and fermentation (SSF), and (3) the stillage from the distillation column . Recovering cellulase present in hydrolysate (hydrolyzed sugar stream) using ultrafiltration was found to be too expensive, and only part of the enzymes that were originally loaded could be recovered, since some enzymes are irreversibly bound to the solid portion .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

In-Situ Vacuum Distillation of Ethanol Helps To Recycle Cellulase and Yeast during SSF of Delignified Corncob Residues

Zhang

Liu

et al. 2017

ACS Sustainable Chem. Eng.

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The high cost of the lignocellulose-degrading enzyme is one of the major bottlenecks for economically producing cellulosic ethanol. To overcome this bottleneck, we performed in-situ vacuum distillation (at 50 °C, 77 mmHg for 30 min) to remove ethanol after simultaneous saccharification and fermentation (SSF) of delignified corncob residues (DCCR). The cellulase and yeast cells left in the stillage were reused by adding fresh DCCR to start a new cycle. This process cycle was repeated five times. Both cellulase and yeast cells were reused five times with a significant cellulase reduction from 16.3 mg of enzyme protein (EP)/g cellulose to as low as 3.3 mg EP/g cellulose. Meanwhile the ethanol in the fermentation broth was maintained as high as 40 g/L before each vacuum distillation. The final ethanol yield after five cycles reached 72.7%. The process economic analysis based on the Aspen Plus model indicated that the cost of the saved cellulase was much higher than that of the additional energy needed to carry out the vacuum distillation. Almost 24% of the ethanol production cost could be reduced by using this new approach compared to batch SSF without cellulase recycling.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In-Situ Vacuum Distillation of Ethanol Helps To Recycle Cellulase and Yeast during SSF of Delignified Corncob Residues

Zhang

Liu

et al. 2017

ACS Sustainable Chem. Eng.

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“…Often, remaining enzymes will destabilize a bioproduct, if not removed or captured. Likewise, recycling the enzyme can facilitate production and can reduce the cost of biotechnological processes . So, there is a need for capturing, packaging, protecting, and releasing proteins.…”

Section: Introductionmentioning

confidence: 99%

Capturing and Stabilizing Folded Proteins in Lattices Formed with Branched Oligonucleotide Hybrids

2018

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The encapsulation of folded proteins in stabilizing matrices is one of the challenges of soft-matter materials science. Capturing such fragile bio-macromolecules from aqueous solution, and embedding them in a lattice that stabilizes them against denaturation and decomposition is difficult. Here, we report that tetrahedral oligonucleotide hybrids as branching elements, and connecting DNA duplexes with sticky ends can assemble into materials. The material-forming property was used to capture DNA-binding proteins selectively from aqueous protein mixtures. The three-dimensional networks also encapsulate guest molecules in a size-selective manner, accommodating proteins up to a molecular weight of approximately 159 kDa for the connecting duplex lengths tested. Exploratory experiments with green fluorescent protein showed that, when embedded in the DNA-based matrix, the protein is more stable toward denaturation than in the free form, and retains its luminescent properties for at least 90 days in dry form. The noncrystalline biohybrid matrices presented herein may be used for capturing other proteins or for producing functional materials.

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“…After high solid loading, especially in conjunction with hydrolysis following high solid pretreatment, the high the concentration of reducing sugars, the high the ethanol concentration and, thus, it led to the low the bioethanol purification cost, reduced the economic cost of the fermentation or facilities, and the simplified process [21]. Dr. Jin group in Nanjing confirmed that high solids loadings (> 18, wt%) process in enzymatic hydrolysis and fermentation result in high bioethanol production at a low cost [22]. Jin group has integrated ethanol production and fermentation process including dilute alkali or acid pretreatment, substrate mixture ratios and solids loadings from mixtures of corn and corn stover, which are as very rich resources as lignocellulosic feedstocks in China [23,24].…”

mentioning

confidence: 99%

Metabolic and evolutionary engineering of diploid yeast for the production of first-and second-generation ethanol

Sun

Xue

Hou

et al. 2020

Preprint

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Background: Saccharomyces cerevisiae has been widely used in the fermentation of plant-derived sugars to produce ethanol, called first-generation (1G) bioethanol, but made an impact on global food markets. Significant efforts have been therefore to employ non-food lignocellulosic feedstocks for bioethanol production, known as second-generation (2G) bioethanol. However, S. cerevisiae cannot naturally utilize xylose, a major component in lignocellulosic hydrolysates, and it has low tolerance to common carboxylic acid inhibitors present in lignocellulosic hydrolyzates. Metabolic engineering and evolutionary engineering have shown great power in strain improvement, which were also adopted here to solve these limiting factors in developing 2G bioethanol.Results: An efficient expression of a six-gene cluster, including XYL1/XYL2/XKS1/TAL1/PYK1/MGT05196, was achieved in the evolved S. cerevisiae diploid strain A21Z, showing the ability to use mixed glucose and xylose. The engineered strain A21Z expressing the six-gene cluster displayed a high xylose consumption after 96 h, reaching 90.7% of the theoretical yield in ethanol production. To investigate its industrial characteristics, A31Z was obtained by direct evolution of A21Z under the treatment of industrial hydrolysate from wheat straw. Under different fermentation conditions with 1G and 2G feedstock candidates, A31Z showed a markedly improved xylose fermentation performance. A31Z could produce more ethanol and less glycerol compared to the control Angel from corn starch during 120 h, with a final ethanol production at 122.32 g/L. The ability to produce higher ethanol production was also found under the fermentation using carbon source from hydrolysis of Dried Distillers Grains with Solubles (DDGS) or whole corn.Conclusions: Here, we report an effective strategy to improve xylose fermentation with an evolutionary engineering in the industrial S. cerevisiae diploid strain A31Z. This study demonstrated that a constructed A31Z has the higher xylose consumption and efficient ethanol production in mixed glucose and xylose with acetate. A31Z also gave a good ethanol production in 1G and 2G industrial feedstocks, indicating its significant contribution in the transition stage from the 1st generation to the 2nd generation bioethanol.

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Development of rapid bioconversion with integrated recycle technology for ethanol production from extractive ammonia pretreated corn stover

Cited by 15 publications

References 24 publications

In-Situ Vacuum Distillation of Ethanol Helps To Recycle Cellulase and Yeast during SSF of Delignified Corncob Residues

In-Situ Vacuum Distillation of Ethanol Helps To Recycle Cellulase and Yeast during SSF of Delignified Corncob Residues

Capturing and Stabilizing Folded Proteins in Lattices Formed with Branched Oligonucleotide Hybrids

Metabolic and evolutionary engineering of diploid yeast for the production of first-and second-generation ethanol

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