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Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii.

Joyce BL, Zheljazkov VD, Sykes R, Cantrell CL, Hamilton C, Mann DG, Rodriguez M, Mielenz JR, Astatkie T, Stewart CN - PLoS ONE (2015)

Bottom Line: The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass).Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass.Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, United States of America.

ABSTRACT
Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass)-1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.

No MeSH data available.


Final ethanol yield (mg g-1 biomass) of lemongrass and palmarosa biomass that was (EX) or was not (NE) previously extracted for essential oils in comparison to two lots of BioEnergy Science Center (BESC) control switchgrass.A) Final ethanol concentration of biomass that was not pretreated in fermentation liquids. B) Final ethanol yield (mg g-1 biomass) of dilute acid pretreated lemongrass and palmarosa biomass that was (EX) or was not (NE) extracted for essential oils in comparison to lot #1 BESC control switchgrass.
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pone.0139195.g005: Final ethanol yield (mg g-1 biomass) of lemongrass and palmarosa biomass that was (EX) or was not (NE) previously extracted for essential oils in comparison to two lots of BioEnergy Science Center (BESC) control switchgrass.A) Final ethanol concentration of biomass that was not pretreated in fermentation liquids. B) Final ethanol yield (mg g-1 biomass) of dilute acid pretreated lemongrass and palmarosa biomass that was (EX) or was not (NE) extracted for essential oils in comparison to lot #1 BESC control switchgrass.

Mentions: Benchtop-scale simultaneous saccharification and fermentation (SSF) was carried out to investigate the potential to produce biofuels, i.e. ethanol in this work, from lemongrass and palmarosa biomass and how the role of secondary metabolites found in these two species might affect biofuel production efficiency. Bench-top SSF experiments model lignocellulosic biorefinery process to determine suitability of biomass after pretreatment. Lemongrass extracted (EX) biomass yielded less ethanol than not-extracted biomass (NE), but EX palmarosa biomass yielded more ethanol than NE palmarosa biomass (Fig 5A). These patterns were the same in biomass treated with and without enzyme, suggesting that results were from biomass properties, rather than inhibition of enzymatic hydrolysis. Lemongrass and palmarosa essential oils were found to interact with S. cerevisiae cell membranes and cause the leakage of ions until cellular death [6,7]. These two reports found a concentration of 0.1% for either lemongrass or palmarosa essential oil was toxic to S. cerevisiae. The major essential oil constituents of lemongrass (citral) and palmarosa (geraniol) have low solubility in water because they are primarily nonpolar terpenoid hydrocarbons; however, geranial is 38.8% more soluble in water, 420 mg L-1 and 686 mg L-1 at 20°C respectively (GESTIS database, October 2012). Therefore, fermentation of palmarosa biomass could result in S. cerevisiae toxicity in relatively lower biomass concentrations than lemongrass or switchgrass as observed (Fig 5A). These considerations support two different mechanisms for the difference in ethanol fermentation potential from lemongrass and palmarosa. First, lemongrass biomass losses fermentable glucose by steam distillation which leads to higher ethanol yields from not-extracted biomass. Alternatively, the essential oil present in palmarosa may inhibit S. cerevisiae fermentation, which leads to higher ethanol yields from biomass that has had the essential oils removed through steam distillation.


Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii.

Joyce BL, Zheljazkov VD, Sykes R, Cantrell CL, Hamilton C, Mann DG, Rodriguez M, Mielenz JR, Astatkie T, Stewart CN - PLoS ONE (2015)

Final ethanol yield (mg g-1 biomass) of lemongrass and palmarosa biomass that was (EX) or was not (NE) previously extracted for essential oils in comparison to two lots of BioEnergy Science Center (BESC) control switchgrass.A) Final ethanol concentration of biomass that was not pretreated in fermentation liquids. B) Final ethanol yield (mg g-1 biomass) of dilute acid pretreated lemongrass and palmarosa biomass that was (EX) or was not (NE) extracted for essential oils in comparison to lot #1 BESC control switchgrass.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593581&req=5

pone.0139195.g005: Final ethanol yield (mg g-1 biomass) of lemongrass and palmarosa biomass that was (EX) or was not (NE) previously extracted for essential oils in comparison to two lots of BioEnergy Science Center (BESC) control switchgrass.A) Final ethanol concentration of biomass that was not pretreated in fermentation liquids. B) Final ethanol yield (mg g-1 biomass) of dilute acid pretreated lemongrass and palmarosa biomass that was (EX) or was not (NE) extracted for essential oils in comparison to lot #1 BESC control switchgrass.
Mentions: Benchtop-scale simultaneous saccharification and fermentation (SSF) was carried out to investigate the potential to produce biofuels, i.e. ethanol in this work, from lemongrass and palmarosa biomass and how the role of secondary metabolites found in these two species might affect biofuel production efficiency. Bench-top SSF experiments model lignocellulosic biorefinery process to determine suitability of biomass after pretreatment. Lemongrass extracted (EX) biomass yielded less ethanol than not-extracted biomass (NE), but EX palmarosa biomass yielded more ethanol than NE palmarosa biomass (Fig 5A). These patterns were the same in biomass treated with and without enzyme, suggesting that results were from biomass properties, rather than inhibition of enzymatic hydrolysis. Lemongrass and palmarosa essential oils were found to interact with S. cerevisiae cell membranes and cause the leakage of ions until cellular death [6,7]. These two reports found a concentration of 0.1% for either lemongrass or palmarosa essential oil was toxic to S. cerevisiae. The major essential oil constituents of lemongrass (citral) and palmarosa (geraniol) have low solubility in water because they are primarily nonpolar terpenoid hydrocarbons; however, geranial is 38.8% more soluble in water, 420 mg L-1 and 686 mg L-1 at 20°C respectively (GESTIS database, October 2012). Therefore, fermentation of palmarosa biomass could result in S. cerevisiae toxicity in relatively lower biomass concentrations than lemongrass or switchgrass as observed (Fig 5A). These considerations support two different mechanisms for the difference in ethanol fermentation potential from lemongrass and palmarosa. First, lemongrass biomass losses fermentable glucose by steam distillation which leads to higher ethanol yields from not-extracted biomass. Alternatively, the essential oil present in palmarosa may inhibit S. cerevisiae fermentation, which leads to higher ethanol yields from biomass that has had the essential oils removed through steam distillation.

Bottom Line: The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass).Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass.Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, United States of America.

ABSTRACT
Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass)-1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.

No MeSH data available.