Enhancement of ethanol production by promoting surface contact between starch granules and arming yeast in direct ethanol fermentation

Khaw, Teik Seong; Katakura, Yoshio; Ninomiya, Kazuaki; Moukamnerd, Churairat; Kondo, Akihiko; Ueda, Mitsuyoshi; Shioya, Suteaki

doi:10.1263/jbb.103.95

Cited by 31 publications

(13 citation statements)

References 4 publications

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“…Judged from the observation that glucoamylase degraded gelatinized starch to simple sugar for yeasts fermentation, and our fusant cell displayed glucoamylase, α-amylase, and acid protease which may enhance the distribution of the other constituents in the starchy material-like rice grain. Similar situation have been found where the arming yeast cells displaying glucoamylase and α-amylase increased the surface contact between starch granules and yeast cells, and thus increased the alcohol production rate as reported by Khaw et al [23]. The flavor components of the rice spirits that were fermented by the fusant were analyzed.…”

Section: Brewing Test Of the Fusant And The Parental Strainssupporting

confidence: 76%

“…In this process, various kinds of enzymes in rice koji and wheat koji are used to dissolve and saccharify steamed rice, and then the yeast cells can be used to ferment the simple sugars into alcohol [22]. Among these enzymes, α-amylase, glucoamylase, and acid protease, which are able to participate in breaking down starchy materials into simple sugars and other components that yeast can use to ferment, are of great importance [23,24]. The fusant and its parental strains were separately inoculated on steamed rice to make rice koji in order to investigate their performances in enzyme production.…”

Section: Enzyme Activity Assaysmentioning

confidence: 99%

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Breeding an Amylolytic Yeast Strain for Alcoholic Beverage Production

Cheng

Chang

Dent

et al. 2010

Appl Biochem Biotechnol

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A starch-utilizing, yeast-like fusant was successfully created from fused protoplasts of Schizosaccharomyces pombe and Monascus anka, and the feasibility of using this fusant as a new strain for alcoholic beverage development was reported. The new fusant utilized various carbon sources more efficiently than its parent cells did. Rice koji prepared separately by cultivating the fusant and its parental strains on rice was compared to explore the effect of yeast strain on the production of α-amylase, glucoamylase, and acid protease that are crucial in wine making using cereal grains. It was found that the fusant produced greater levels of the above-mentioned enzymes than its parental strain does. Consequently, the usage of this fusant in the alcoholic fermentation of polished rice was found to reduce approximately 50% consumption of added glucoamylase than when its parental strain was used. Besides, at the end of fermentation, the fusant yeast resulted in a mash with distribution of flavor components very different from that produced by its parental strains. Thus, the fusant can be used as a new yeast strain for creating novel alcoholic beverages.

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Section: Brewing Test Of the Fusant And The Parental Strainssupporting

confidence: 76%

Section: Enzyme Activity Assaysmentioning

confidence: 99%

Breeding an Amylolytic Yeast Strain for Alcoholic Beverage Production

Cheng

Chang

Dent

et al. 2010

Appl Biochem Biotechnol

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“…In this current study, however, low solid concentrations, short incubation times and a shaken system were applied, so cellulase inactivation could be neglected. Moreover, upon using immobilized or displayed cellulases [91-93], lower shaking frequencies are beneficial to ensure sufficient surface contact between cellulase and solid substrate [94]. In comparison to the adsorption parameters, a disproportionate increase in cellulase activity was observed with enhanced agitation (Figure 6A and B).…”

Section: Resultsmentioning

confidence: 99%

Practical screening of purified cellobiohydrolases and endoglucanases with α-cellulose and specification of hydrodynamics

Jäger

Garschhammer

et al. 2010

Biotechnol Biofuels

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BackgroundIt is important to generate biofuels and society must be weaned from its dependency on fossil fuels. In order to produce biofuels, lignocellulose is pretreated and the resulting cellulose is hydrolyzed by cellulases such as cellobiohydrolases (CBH) and endoglucanases (EG). Until now, the biofuel industry has usually applied impractical celluloses to screen for cellulases capable of degrading naturally occurring, insoluble cellulose. This study investigates how these cellulases adsorb and hydrolyze insoluble α-cellulose − considered to be a more practical substrate which mimics the alkaline-pretreated biomass used in biorefineries. Moreover, this study investigates how hydrodynamics affects cellulase adsorption and activity onto α-cellulose.ResultsFirst, the cellulases CBH I, CBH II, EG I and EG II were purified from Trichoderma reesei and CBH I and EG I were utilized in order to study and model the adsorption isotherms (Langmuir) and kinetics (pseudo-first-order). Second, the adsorption kinetics and cellulase activities were studied under different hydrodynamic conditions, including liquid mixing and particle suspension. Third, in order to compare α-cellulose with three typically used celluloses, the exact cellulase activities towards all four substrates were measured.It was found that, using α-cellulose, the adsorption models fitted to the experimental data and yielded parameters comparable to those for filter paper. Moreover, it was determined that higher shaking frequencies clearly improved the adsorption of cellulases onto α-cellulose and thus bolstered their activity. Complete suspension of α-cellulose particles was the optimal operating condition in order to ensure efficient cellulase adsorption and activity. Finally, all four purified cellulases displayed comparable activities only on insoluble α-cellulose.Conclusionsα-Cellulose is an excellent substrate to screen for CBHs and EGs. This current investigation shows in detail, for the first time, the adsorption of purified cellulases onto α-cellulose, the effect of hydrodynamics on cellulase adsorption and the correlation between the adsorption and the activity of cellulases at different hydrodynamic conditions. Complete suspension of the substrate has to be ensured in order to optimize the cellulase attack. In the future, screenings should be conducted with α-cellulose so that proper cellulases are selected to best hydrolyze the real alkaline-pretreated biomass used in biorefineries.

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“…Bioethanol as a renewable energy source is becoming more important in society particularly because of growing concerns with the use of fossil fuels coupled with the impact it has to the environment [1]. Its (bioethanol) production based on the use of renewable feedstock such as agricultural products involves the use of competitive technologies to meet different energy market demands [2].…”

Section: Introductionmentioning

confidence: 99%

Ethanol Production by Alcohol Tolerant Yeasts Using Different Carbohydrate Sources

Maxwell¹,

Anna²,

Akpan³

et al. 2017

AAS

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Abstract:This study aimed at comparing the ability of two indigenous yeast species; Pichia kudriavzevii strains GY1 and L9 with a strain of Saccharomyces cerevisiae, to consume sugars (fructose, galactose, glucose, lactose, sucrose and molasses) and to convert them into ethanol during fermentation. Yeast extract (6g/L), peptone (10g/L), malt extract (6g/L) broth was supplemented with different concentrations (5g/L, 10g/L, 20g/L, 30g/L) of fructose, galactose, glucose, lactose and sucrose respectively. Sugar utilization post incubation for 96 hours at 120 rpm, 30 degree Celsius (°C) was measured using a refractometer. The alcoholic yield using molasses for Pichia kudriavzevii strain GY1 10±0.2 (mg/ml) was significantly higher than that of Pichia kudriavzevii strain L9 (4±0.2 mg/ml) and Saccharomyces cerevisiae strain T (5±0.2 mg/ml) at 96 hours. Strains that produced highest concentration ethanol was Pichia kudriavzevii strain L9 in 3.0% (v/v) galactose and fructose respectively, which measured at 7.1±0.48 (mg/ml) and 12.2±0.64 (mg/ml). All studied isolates produced the same amount of ethanol 9.1±0.52 (mg/ml). The use of highly adaptable non Saccharomyces yeast species to a variety of sugars in the pursuit of enhanced ethanol production creates a unique prospective for large scale industrial applications.

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Enhancement of ethanol production by promoting surface contact between starch granules and arming yeast in direct ethanol fermentation

Cited by 31 publications

References 4 publications

Breeding an Amylolytic Yeast Strain for Alcoholic Beverage Production

Breeding an Amylolytic Yeast Strain for Alcoholic Beverage Production

Practical screening of purified cellobiohydrolases and endoglucanases with α-cellulose and specification of hydrodynamics

Ethanol Production by Alcohol Tolerant Yeasts Using Different Carbohydrate Sources

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