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Molecular structure of photosynthetic microbial biofuels for improved engine combustion and emissions characteristics.

Hellier P, Purton S, Ladommatos N - Front Bioeng Biotechnol (2015)

Bottom Line: These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace.Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion.This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University College London , London , UK.

ABSTRACT
The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

No MeSH data available.


Effect of C18 fatty acid saturated ester alcohol moiety straight carbon chain length on total particulate mass emissions. Adapted with permission from Hellier et al. (2012). Copyright ©2012 American Chemical Society.
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Figure 7: Effect of C18 fatty acid saturated ester alcohol moiety straight carbon chain length on total particulate mass emissions. Adapted with permission from Hellier et al. (2012). Copyright ©2012 American Chemical Society.

Mentions: Figure 7 shows the effect of increasing the straight carbon chain length of the alcohol moiety of a saturated fatty acid ester (of alkyl moiety chain length 18) on emission of PM (Hellier et al., 2012). In this study, no clear influence of substituting the methyl alcohol moiety of the fatty acid ester with ethyl, propyl, and butyl alcohol moieties on the duration of fuel ignition delay was observed (Hellier et al., 2012) [in agreement with other investigations (Allen et al., 2013)]. However, in Figure 7 it can be seen that an increase in the fatty acid ester alcohol moiety results in a significant increase in the production of PM. This increase with alcohol moiety length coincides with a decreasing molecular oxygen content and increasing viscosities and boiling points (Hellier et al., 2012), all of which can be expected to result in increased particulate formation and emission (Tree and Svensson, 2007). A saturated C18 fatty acid iso-butyl ester was also tested under the same conditions as the results presented in Figure 7, and found to emit levels of PM similar to those observed from the equivalent n-propyl ester (Hellier et al., 2012). Therefore, in the utilization of short chain alcohols from photosynthetic micro-organisms to form fatty acid esters, consideration should be given as to whether the resultant physical properties of the ester may produce elevated emissions of PM.


Molecular structure of photosynthetic microbial biofuels for improved engine combustion and emissions characteristics.

Hellier P, Purton S, Ladommatos N - Front Bioeng Biotechnol (2015)

Effect of C18 fatty acid saturated ester alcohol moiety straight carbon chain length on total particulate mass emissions. Adapted with permission from Hellier et al. (2012). Copyright ©2012 American Chemical Society.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403606&req=5

Figure 7: Effect of C18 fatty acid saturated ester alcohol moiety straight carbon chain length on total particulate mass emissions. Adapted with permission from Hellier et al. (2012). Copyright ©2012 American Chemical Society.
Mentions: Figure 7 shows the effect of increasing the straight carbon chain length of the alcohol moiety of a saturated fatty acid ester (of alkyl moiety chain length 18) on emission of PM (Hellier et al., 2012). In this study, no clear influence of substituting the methyl alcohol moiety of the fatty acid ester with ethyl, propyl, and butyl alcohol moieties on the duration of fuel ignition delay was observed (Hellier et al., 2012) [in agreement with other investigations (Allen et al., 2013)]. However, in Figure 7 it can be seen that an increase in the fatty acid ester alcohol moiety results in a significant increase in the production of PM. This increase with alcohol moiety length coincides with a decreasing molecular oxygen content and increasing viscosities and boiling points (Hellier et al., 2012), all of which can be expected to result in increased particulate formation and emission (Tree and Svensson, 2007). A saturated C18 fatty acid iso-butyl ester was also tested under the same conditions as the results presented in Figure 7, and found to emit levels of PM similar to those observed from the equivalent n-propyl ester (Hellier et al., 2012). Therefore, in the utilization of short chain alcohols from photosynthetic micro-organisms to form fatty acid esters, consideration should be given as to whether the resultant physical properties of the ester may produce elevated emissions of PM.

Bottom Line: These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace.Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion.This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University College London , London , UK.

ABSTRACT
The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

No MeSH data available.