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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.


Related in: MedlinePlus

Net ethanol (a) and acetic acid (b) yields by C. cellulolyticum after 20-day fermentation on red and white grape pomace that was raw (raw: grey), pretreated and pressed (pret press: black), and pretreated and washed (pret wash: horizontal lines).
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fig2: Net ethanol (a) and acetic acid (b) yields by C. cellulolyticum after 20-day fermentation on red and white grape pomace that was raw (raw: grey), pretreated and pressed (pret press: black), and pretreated and washed (pret wash: horizontal lines).

Mentions: The main products of C. cellulolyticum on grape pomace were ethanol and acetic acid. Small amounts of propionic, butyric, and valeric acids were also produced. The raw red grape pomace appeared to have the highest ethanol yield of 0.13 g/gVS, but it also had the highest initial ethanol concentration. The net ethanol production was actually slightly negative over time. All other treatments resulted in a net increase in ethanol yield over time. In order to compare the net increase in ethanol produced by C. cellulolyticum, the initial ethanol was subtracted from the 20-day data, with the negatives set to zero. The net ethanol production data are shown in Figure 2. All of the ethanol yields are similar except for the raw red pomace, which had no net increase in ethanol production. The highest ethanol yield of 0.09 g/gVS was from the pretreated and pressed red pomace. The pretreated and pressed white pomace had the highest total product yield of 0.16 g/gVS.


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

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

Net ethanol (a) and acetic acid (b) yields by C. cellulolyticum after 20-day fermentation on red and white grape pomace that was raw (raw: grey), pretreated and pressed (pret press: black), and pretreated and washed (pret wash: horizontal lines).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig2: Net ethanol (a) and acetic acid (b) yields by C. cellulolyticum after 20-day fermentation on red and white grape pomace that was raw (raw: grey), pretreated and pressed (pret press: black), and pretreated and washed (pret wash: horizontal lines).
Mentions: The main products of C. cellulolyticum on grape pomace were ethanol and acetic acid. Small amounts of propionic, butyric, and valeric acids were also produced. The raw red grape pomace appeared to have the highest ethanol yield of 0.13 g/gVS, but it also had the highest initial ethanol concentration. The net ethanol production was actually slightly negative over time. All other treatments resulted in a net increase in ethanol yield over time. In order to compare the net increase in ethanol produced by C. cellulolyticum, the initial ethanol was subtracted from the 20-day data, with the negatives set to zero. The net ethanol production data are shown in Figure 2. All of the ethanol yields are similar except for the raw red pomace, which had no net increase in ethanol production. The highest ethanol yield of 0.09 g/gVS was from the pretreated and pressed red pomace. The pretreated and pressed white pomace had the highest total product yield of 0.16 g/gVS.

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.


Related in: MedlinePlus