In situ pretreatment during distillation improves corn fiber conversion and ethanol yield in the dry mill process

Abstract Background: The technology of converting corn mashes to ethanol has been mature, but corn mashes has high-viscosity and high-sugar characteristics which hindered cellulose utilization and yeast-fermentation efficiency. The excessive viscosity of corn mash is caused by the presence of non-starch polysaccharides, such as cellulose in cereal grains. Corn kernel fiber (mostly cellulose) is typically unconverted in the process. Results: A novel lignocellulolytic enzymes cocktail with strong substrate specificity was prepared for high-viscosity, high-sugar corn mash. The in situ conversion of corn mashes with novel lignocellulolytic enzymes at the optimum cellulase dosage of 50 FPU/L resulted in 12.4%, 12.0%, 11.8%, and 12.9% increased ethanol concentration compared with the reference mash at 0.3, 1, 5, and 70 L batch-fermentation scales, respectively. The highest yield of ethanol from corn mash digested with the prepared novel lignocellulolytic enzyme reached 117.0 ± 0.1g/L at the 70 L batch fermentation, which was a 12.9% increase in ethanol yield. Adding the lignocellulolytic enzymes caused the greatest decrease in viscosity of corn mash by 40.9% compared with the reference mash (33.5 ± 1.5 Pa·s), whereas the residual sugars decreased by 56.3%. Simultaneously, the application of novel lignocellulolytic enzymes increased the value of dried distiller’s grain with solubles by increasing the protein content and decreasing the residual cellulose and starch content.Conclusion: The application of novel lignocellulolytic enzymes significantly improved the alcohol concentration, productivity, and yield. With the same amount of material, the application of the novel enzymes cocktail can enhance the ethanol yield by more than 10%. The in situ conversion of cellulose promoted the release of contents, including starch and protein, which can decrease the fermentation broth viscosity and improve the rheological property, thereby improving the ethanol yield. Thus, this technology can increase the net revenue of fuel-ethanol industrialization and promote the technological progress of renewable energy.

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In-situ corn fiber conversion method unlocks the role of viscosity on enhancing ethanol yield by reducing side-product glycerol

Industrial Crops and Products ◽

10.1016/j.indcrop.2021.113653 ◽

2021 ◽

Vol 169 ◽

pp. 113653

Author(s):

Xiujuan Li ◽

Qiang Xiong ◽

Minghui Wang ◽

He Huang ◽

Guojun Yue ◽

...

Keyword(s):

Ethanol Yield ◽

Corn Fiber ◽

Side Product ◽

Conversion Method

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Ethanol Production from Different Substrates by a Flocculent Saccharomyces cerevisiae Strain

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1917 ◽

2009 ◽

Vol 7 (1) ◽

Cited By ~ 4

Author(s):

José Duarte ◽

Vera Lourenço ◽

Belina Ribeiro ◽

Maria Céu Saagua ◽

Joana Pereira ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Ethanol Production ◽

Yeast Strain ◽

Fossil Fuels ◽

Ethanol Yield ◽

Corn Fiber ◽

Production Costs ◽

Raw Material ◽

Continuous Reactor ◽

Different Strains

During the last years there has been an increasing interest in using ethanol as a substitute for fossil fuels. The bioethanol used today is mainly produced from sugar cane and cereals, but reducing the production costs of ethanol is still crucial for a viable economic process. Cellulose from vegetable biomass will be the next cheap raw material for second generation fuel ethanol production and agricultural by-products with a low commercial value, as corn stover, corn fiber and cane bagasses would become an attractive feedstock for bioethanol production.In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in a synthetic liquid medium containing sucrose in batch regime and the growth rates, ethanol and biomass productions were determined as well as their growth ability in cane molasses.The results indicate that a flocculent yeast, isolated in our lab and designated by strain F, was the most promising yeast strain among those tested for continuous ethanol production. This strain was isolated from corn hydrolysates, obtained from a Portuguese distillery facility (DVT, Torres Novas, Portugal) showing highest growth rate (0.49h-1), highest ethanol yield (0.35g/g) and high flocculation capacity.The study on ethanol production in continuous reactor process with the selected yeast strain (strain F) was made on sucrose and cane molasses at different dilution rates (0.05-0.42 h-1). A steady flocculating yeast fluidized bed reactor system was established allowing the functioning of the reactor for 1000 h. Data shows that when the dilution rate rose to 0.42h-1, the highest productivity (20g/Lh) was obtained attaining an ethanol concentration in the reactor of 47g/L for sucrose and molasses media.

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Comparison of Enzymatic and Acidic Fractionation of Corn Fiber for Glucose-rich Hydrolysate and Bioethanol Production by Candida boidinii

Periodica Polytechnica Chemical Engineering ◽

10.3311/ppch.17431 ◽

2021 ◽

Author(s):

Anikó Fehér ◽

Soma Bedő ◽

Csaba Fehér

Keyword(s):

Ethanol Fermentation ◽

Dry Matter ◽

Ethanol Yield ◽

Cellulose Hydrolysis ◽

Ammonia Solution ◽

Corn Fiber ◽

Raw Material ◽

Candida Boidinii ◽

Wet Milling ◽

Fractionation Process

Corn fiber is a by-product of the corn wet milling process and a promising raw material to produce bioethanol in a bio-refinery process. In this study, enzymatic and acidic fractionations of corn fiber were compared with particular attention to produce glucose-rich hydrolyzates. The acidic fractionation contained two, sequential, sulphuric acid-catalyzed, hydrolysis steps based on our previous study. In the enzymatic fractionation process, corn fiber was pre-treated by soaking in aqueous ammonia (18.5 % (w/w) dry matter, 15 % (w/w) ammonia solution, 24 hours) and then hydrolyzed by using Hemicellulase (NS 22002) enzyme cocktail. The cellulose part of the solid residues obtained after the acidic and enzymatic fractionation processes was enzymatically hydrolyzed by using Cellic Ctec2 and Novozymes 188 (12.5 % (w/w) dry matter, 50 °C, 72 hours). Cellulose hydrolysis after the acidic and enzymatic fractionation resulted in a supernatant containing 64 g/L and 25 g/L glucose, respectively. Therefore, ethanol fermentation experiments were performed in Separated Hydrolysis and Fermentation (SHF) and Simultaneous Saccharification and Fermentation (SSF) configurations after the acidic fractionation of corn fiber. SHF configuration was found to be more advantageous regarding the achievable ethanol yield. Although the fermentation with Candida boidinii NCAIM Y.01308 was accomplished within longer time (43 hours) compared to Saccharomyces cerevisiae (5 hours), the achieved ethanol yields were similar (79%) during the SHF process. It was concluded that acidic fractionation is more efficient to produce glucose-rich hydrolyzate from corn fiber compared to enzymatic fractionation, and Candida boidinii is suitable for ethanol fermentation on the glucose-rich hydrolyzate.

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Ethanol production via in situ fungal saccharification and fermentation of mild alkali and steam pretreated corn fiber

Bioresource Technology ◽

10.1016/j.biortech.2010.06.089 ◽

2010 ◽

Vol 101 (22) ◽

pp. 8698-8705 ◽

Cited By ~ 24

Author(s):

Prachand Shrestha ◽

Samir Kumar Khanal ◽

Anthony L. Pometto ◽

J. (Hans) van Leeuwen

Keyword(s):

Ethanol Production ◽

Corn Fiber

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A one-pot microwave-assisted NaCl–H2O/GVL solvent system for cellulose conversion to 5-hydroxymethylfurfural and saccharides with in situ separation of the products

Cellulose ◽

10.1007/s10570-019-02362-8 ◽

2019 ◽

Vol 26 (15) ◽

pp. 8383-8400 ◽

Cited By ~ 1

Author(s):

Zhicheng Jiang ◽

Javier Remón ◽

Tianzong Li ◽

Vitaliy L. Budarin ◽

Jiajun Fan ◽

...

Keyword(s):

Solvent System ◽

One Pot ◽

Cellulose Conversion ◽

Microwave Assisted ◽

In Situ Separation

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Rendez vous with Saturn's rings

International Astronomical Union Colloquium ◽

10.1017/s0252921100101885 ◽

1984 ◽

Vol 75 ◽

pp. 743-759 ◽

Cited By ~ 2

Author(s):

Kerry T. Nock

Keyword(s):

Solar Energy ◽

Electric Propulsion ◽

Power Source ◽

Propulsion System ◽

Low Thrust ◽

Ring Plane ◽

The Earth ◽

Total Impulse ◽

Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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