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Ethanol and Volatile Fatty Acid Production from Lignocellulose by Clostridium cellulolyticum.

Williams K, Zheng Y, McGarvey J, Fan Z, Zhang R - ISRN Biotechnol (2012)

Bottom Line: Sterilization appeared to decrease native acetogen populations in the rice straw, resulting in lower acetic acid yields.Pomace type (red or white) and washing were found to be not significant.Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68 and 79%.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, Davis, CA 95616, USA.

ABSTRACT
Clostridium cellulolyticum is capable of producing glycosyl hydrolase enzymes as well as fermentation products including ethanol and acetate. In this study, the potential of using C. cellulolyticum for ethanol and volatile fatty acid production from straw and grape pomace was examined. For rice straw, the effects of alkaline pretreatment and substrate sterilization prior to fermentation on products yields were also investigated. Effects of alkaline pretreatment and necessity for subsequent washing were tested for two types of grape pomace. For rice straw, the highest ethanol yield was 0.16 g/gVS from the straw pretreated with 10% sodium hydroxide loading at 121°C for 1 hour. Sterilization of the straw prior to fermentation was found to be not significant for ethanol production. Sterilization appeared to decrease native acetogen populations in the rice straw, resulting in lower acetic acid yields. The highest ethanol yield from grape pomace was of 0.09 g/gVS from the pretreated pomace. Pomace type (red or white) and washing were found to be not significant. Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68 and 79%.

No MeSH data available.


C. cellulolyticum product yields after 20 days from rice straw that was high-temperature pretreated, unsterilized (HT-U: white), low-temperature pretreated, unsterilized (LT-U: diagonal lines), raw, unsterilized (R-U: black), high-temperature pretreated, sterilized (HT-S: horizontal lines), high-temperature pretreated, sterilized (R-S: grey).
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Related In: Results  -  Collection


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fig1: C. cellulolyticum product yields after 20 days from rice straw that was high-temperature pretreated, unsterilized (HT-U: white), low-temperature pretreated, unsterilized (LT-U: diagonal lines), raw, unsterilized (R-U: black), high-temperature pretreated, sterilized (HT-S: horizontal lines), high-temperature pretreated, sterilized (R-S: grey).

Mentions: The product yields for C. cellulolyticum growing on rice straw are shown in Figure 1. The control was subtracted out from each treatment. Ethanol and acetic acid were the main two products. The highest ethanol yield was 0.16 g/gVS, also from the unsterilized high temperature pretreated rice straw. Other products were isobutyric and butyric acid, with yields of 0.05 g/gVS each, from unsterilized high-temperature pretreated rice straw. The highest total product yield was 0.47 g/gVS for the unsterilized high-temperature pretreated straw, which represents 68% conversion of the cellulose and hemicellulose. Ethanol yields got progressively higher as the pretreatment becomes more severe for the nonsterilized rice straw. For the sterilized straws, the difference in ethanol yield between the high-temperature pretreated and raw straws was smaller, suggesting that there is an interaction between sterilization and pretreatment.


Ethanol and Volatile Fatty Acid Production from Lignocellulose by Clostridium cellulolyticum.

Williams K, Zheng Y, McGarvey J, Fan Z, Zhang R - ISRN Biotechnol (2012)

C. cellulolyticum product yields after 20 days from rice straw that was high-temperature pretreated, unsterilized (HT-U: white), low-temperature pretreated, unsterilized (LT-U: diagonal lines), raw, unsterilized (R-U: black), high-temperature pretreated, sterilized (HT-S: horizontal lines), high-temperature pretreated, sterilized (R-S: grey).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4403621&req=5

fig1: C. cellulolyticum product yields after 20 days from rice straw that was high-temperature pretreated, unsterilized (HT-U: white), low-temperature pretreated, unsterilized (LT-U: diagonal lines), raw, unsterilized (R-U: black), high-temperature pretreated, sterilized (HT-S: horizontal lines), high-temperature pretreated, sterilized (R-S: grey).
Mentions: The product yields for C. cellulolyticum growing on rice straw are shown in Figure 1. The control was subtracted out from each treatment. Ethanol and acetic acid were the main two products. The highest ethanol yield was 0.16 g/gVS, also from the unsterilized high temperature pretreated rice straw. Other products were isobutyric and butyric acid, with yields of 0.05 g/gVS each, from unsterilized high-temperature pretreated rice straw. The highest total product yield was 0.47 g/gVS for the unsterilized high-temperature pretreated straw, which represents 68% conversion of the cellulose and hemicellulose. Ethanol yields got progressively higher as the pretreatment becomes more severe for the nonsterilized rice straw. For the sterilized straws, the difference in ethanol yield between the high-temperature pretreated and raw straws was smaller, suggesting that there is an interaction between sterilization and pretreatment.

Bottom Line: Sterilization appeared to decrease native acetogen populations in the rice straw, resulting in lower acetic acid yields.Pomace type (red or white) and washing were found to be not significant.Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68 and 79%.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, Davis, CA 95616, USA.

ABSTRACT
Clostridium cellulolyticum is capable of producing glycosyl hydrolase enzymes as well as fermentation products including ethanol and acetate. In this study, the potential of using C. cellulolyticum for ethanol and volatile fatty acid production from straw and grape pomace was examined. For rice straw, the effects of alkaline pretreatment and substrate sterilization prior to fermentation on products yields were also investigated. Effects of alkaline pretreatment and necessity for subsequent washing were tested for two types of grape pomace. For rice straw, the highest ethanol yield was 0.16 g/gVS from the straw pretreated with 10% sodium hydroxide loading at 121°C for 1 hour. Sterilization of the straw prior to fermentation was found to be not significant for ethanol production. Sterilization appeared to decrease native acetogen populations in the rice straw, resulting in lower acetic acid yields. The highest ethanol yield from grape pomace was of 0.09 g/gVS from the pretreated pomace. Pomace type (red or white) and washing were found to be not significant. Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68 and 79%.

No MeSH data available.