Ethanol production from high dry matter corncob using fed-batch simultaneous saccharification and fermentation after combined pretreatment

Zhang, Mingjia; Fang, Wang; Su, Rongxin; Qi, Wei; He, Zhimin

doi:10.1016/j.biortech.2009.11.010

Cited by 187 publications

(104 citation statements)

References 23 publications

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“…Fibre levels in maize cobs should be reduced to improve their nutritive contribution to pig diets. Fermentation and the use of exogenous enzymes and acids have been reported to reduce fibre content of maize cobs (Latif & Rajoka, 2001;Le Gall et al, 2009;Urriola et al, 2010;Zhang et al, 2010a). However, the use of acids to decrease fibre is unattractive because of safety, and environmental and economic concerns.…”

Section: Introductionmentioning

confidence: 99%

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Kanengoni¹,

Nkosi²,

Chimonyo³

et al. 2016

SA J. An. Sci.

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The study was conducted to assess the effects of whey, molasses and exogenous enzymes on fermentation, aerobic stability and nutrient composition of ensiled maize cobs. Five treatments were ensiled in 1.5 L anaerobic glass jars over 32 days, namely i) control (maize cobs without additives (CON); ii) maize cobs with sugarcane molasses only (MOL); iii) MOL and whey (MOW); iv) MOW and exogenous enzyme at 0.5 g/kg maize cob mixture (ENZ1) and v) MOW and exogenous enzyme at 1 g/kg maize cob mixture (ENZ2). There was a day effect on gross energy (GE) for CON, MOL, ENZ1 and ENZ2 and none for MOW. There was a day effect in ADF for MOL, ENZ1 and ENZ2 and none for CON and MOW. There was lower dry matter (DM) on day 32 compared with day 0 for all treatments. There were treatment effects for GE, crude protein (CP), ash, ether extract, amylase-treated neutral detergent fibre and acid detergent fibre (ADF). On day 32, the neutral detergent fibre (NDF) and ADF concentrations in CON were higher than in MOL, MOW and ENZ2. At day 32, CON silage pH (4.2) was lower than the pH values of ENZ1 (4.5) and ENZ2 (4.6) silages. Acetic acid levels were higher in ENZ1 than ENZ2 silages. Ammonia nitrogen (NH 3 -N) levels averaged 25 ± 6.6 g NH 3 -N/kg total nitrogen, which is indicative of satisfactory ensiling. The MOL, ENZ1 and ENZ2 silages produced more carbon dioxide than CON and MOW silages. The addition of molasses and whey did not improve the nutritive quality of the maize cobs after ensiling. Ensiling maize cobs with molasses, whey and exogenous enzymes resulted in lower DM and fibre levels in the maize cobs, which could enhance intake and digestibility of nutrients when offered to pigs as a component of a balanced diet. Further investigations using higher concentrations of whey and molasses are warranted to improve the energy and protein composition of the maize cobs. ______________________________________________________________________________________

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Section: Introductionmentioning

confidence: 99%

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Kanengoni¹,

Nkosi²,

Chimonyo³

et al. 2016

SA J. An. Sci.

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show abstract

“…Using a biomass fractionation pretreatment upstream will minimize viscosity problems and maximize solids loading during SSF, because the hydrolysate streams will consist primarily of cellulose and hemicellulose, respectively. For example, Zhang et al (2010c) conducted SSF of a pretreated corncob fraction at 19% solids and achieved 69 g/L ethanol. Fed-batch feeding of solids is another method to increase net solids loading (Hodge, et al, 2009;Hoyer, et al, 2010;Varga, et al, 2004).…”

Section: Conversion and Recoverymentioning

confidence: 99%

“…Fed-batch feeding also effectively reduces enzyme dosage. Zhang et al, (2010c) conducted fed batch SSF, achieving a final solid loading of 25% and ethanol titer of 84.7 g/L.…”

Section: Conversion and Recoverymentioning

confidence: 99%

Distributed, Integrated Production of Second and Third Generation Biofuels

Gibbons¹,

Hughes²

2011

Economic Effects of Biofuel Production

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“…Considering these advantages, several energy companies, such as POET, DDCE, and ABENGOA, have chosen corncob as a major feedstock for bioethanol production. Unfortunately, the full commercial deployment of bioethanol bioconversion is challenged by two major obstacles: the high cost of enzymes (Tu et al, 2009) and the recalcitrant block of non-cellulosics (mainly hemicellulose and lignin) (Zhang et al, 2010b).…”

Section: Introductionmentioning

confidence: 99%

“…We previously evaluated a combined pretreatment with dilute sulfuric acid-sodium hydroxide (Zhang et al, 2010b) to increase the relative amount of cellulose and improve the digestibility of corncob during high-solids ethanol fermentation. Although efforts from many researchers and enzyme companies have focused on increasing the production efficiency and specific activity of enzymes, enzyme recycling and reuse is a more practical strategy to reduce enzyme cost (Huang et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Cellulase Recycling after High-Solids Simultaneous Saccharification and Fermentation of Combined Pretreated Corncob

Zhang

et al. 2014

Front. Energy Res.

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Despite the advantageous prospect of second-generation bioethanol, its final commercialization must overcome the primary cost impediment due to enzyme assumption. To solve this problem, this work achieves high-concentration ethanol fermentation and multi-round cellulase recycling through process integration. The optimal time and temperature of the re-adsorption process were determined by monitoring the adsorption kinetics of cellulases. Both glucose and cellobiose inhibited cellulase adsorption. After 96 h of ethanol fermentation, 40% of the initial cellulase remained in the broth, from which 62.5% of the cellulase can be recycled and reused in fresh substrate re-adsorption for 90 min. Under optimum conditions, i.e., pH 5.0, dry matter loading of 15 wt%, cellulase loading of 45 FPU/g glucan, two cycles of fermentation and re-adsorption can yield twofold increased ethanol outputs and reduce enzyme costs by over 50%. The ethanol concentration in each cycle can be achieved at levels >40 g/L.

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Ethanol production from high dry matter corncob using fed-batch simultaneous saccharification and fermentation after combined pretreatment

Cited by 187 publications

References 23 publications

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Distributed, Integrated Production of Second and Third Generation Biofuels

Cellulase Recycling after High-Solids Simultaneous Saccharification and Fermentation of Combined Pretreated Corncob

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