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A systems analysis of biodiesel production from wheat straw using oleaginous yeast : process design, mass and energy balances

Karlsson, Hanna; Ahlgren, Serina; Sandgren, Mats; Passoth, Volkmar; Wallberg, Ola LU and Hansson, Per Anders (2016) In Biotechnology for Biofuels 9(1). p.1-13
Abstract

Background: Biodiesel is the main liquid biofuel in the EU and is currently mainly produced from vegetable oils. Alternative feedstocks are lignocellulosic materials, which provide several benefits compared with many existing feedstocks. This study examined a technical process and its mass and energy balances to gain a systems perspective of combined biodiesel (FAME) and biogas production from straw using oleaginous yeasts. Important process parameters with a determining impact on overall mass and energy balances were identified and evaluated. Results: In the base case, 41% of energy in the biomass was converted to energy products, primary fossil fuel use was 0.37 MJprim/MJ produced and 5.74 MJ fossil fuels could be replaced per kg... (More)

Background: Biodiesel is the main liquid biofuel in the EU and is currently mainly produced from vegetable oils. Alternative feedstocks are lignocellulosic materials, which provide several benefits compared with many existing feedstocks. This study examined a technical process and its mass and energy balances to gain a systems perspective of combined biodiesel (FAME) and biogas production from straw using oleaginous yeasts. Important process parameters with a determining impact on overall mass and energy balances were identified and evaluated. Results: In the base case, 41% of energy in the biomass was converted to energy products, primary fossil fuel use was 0.37 MJprim/MJ produced and 5.74 MJ fossil fuels could be replaced per kg straw dry matter. The electricity and heat produced from burning the lignin were sufficient for process demands except in scenarios where the yeast was dried for lipid extraction. Using the residual yeast cell mass for biogas production greatly increased the energy yield, with biogas contributing 38% of total energy products. Conclusions: In extraction methods without drying the yeast, increasing lipid yield and decreasing the residence time for lipid accumulation are important for the energy and mass balance. Changing the lipid extraction method from wet to dry makes the greatest change to the mass and energy balance. Bioreactor agitation and aeration for lipid accumulation and yeast propagation is energy demanding. Changes in sugar concentration in the hydrolysate and residence times for lipid accumulation greatly affect electricity demand, but have relatively small impacts on fossil energy use (NER) and energy yield (EE). The impact would probably be greater if externally produced electricity were used.

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author
organization
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Contribution to journal
publication status
published
subject
keywords
Biogas, Diesel, Lignocellulosic materials, Microbial oil, Systems perspective
in
Biotechnology for Biofuels
volume
9
issue
1
pages
13 pages
publisher
BioMed Central
external identifiers
  • scopus:84992370267
  • wos:000386092900001
ISSN
1754-6834
DOI
10.1186/s13068-016-0640-9
language
English
LU publication?
yes
id
d4edbb91-488e-4b72-9198-785a8726362e
date added to LUP
2016-11-04 08:43:01
date last changed
2017-11-19 04:34:30
@article{d4edbb91-488e-4b72-9198-785a8726362e,
  abstract     = {<p>Background: Biodiesel is the main liquid biofuel in the EU and is currently mainly produced from vegetable oils. Alternative feedstocks are lignocellulosic materials, which provide several benefits compared with many existing feedstocks. This study examined a technical process and its mass and energy balances to gain a systems perspective of combined biodiesel (FAME) and biogas production from straw using oleaginous yeasts. Important process parameters with a determining impact on overall mass and energy balances were identified and evaluated. Results: In the base case, 41% of energy in the biomass was converted to energy products, primary fossil fuel use was 0.37 MJprim/MJ produced and 5.74 MJ fossil fuels could be replaced per kg straw dry matter. The electricity and heat produced from burning the lignin were sufficient for process demands except in scenarios where the yeast was dried for lipid extraction. Using the residual yeast cell mass for biogas production greatly increased the energy yield, with biogas contributing 38% of total energy products. Conclusions: In extraction methods without drying the yeast, increasing lipid yield and decreasing the residence time for lipid accumulation are important for the energy and mass balance. Changing the lipid extraction method from wet to dry makes the greatest change to the mass and energy balance. Bioreactor agitation and aeration for lipid accumulation and yeast propagation is energy demanding. Changes in sugar concentration in the hydrolysate and residence times for lipid accumulation greatly affect electricity demand, but have relatively small impacts on fossil energy use (NER) and energy yield (EE). The impact would probably be greater if externally produced electricity were used.</p>},
  author       = {Karlsson, Hanna and Ahlgren, Serina and Sandgren, Mats and Passoth, Volkmar and Wallberg, Ola and Hansson, Per Anders},
  issn         = {1754-6834},
  keyword      = {Biogas,Diesel,Lignocellulosic materials,Microbial oil,Systems perspective},
  language     = {eng},
  month        = {10},
  number       = {1},
  pages        = {1--13},
  publisher    = {BioMed Central},
  series       = {Biotechnology for Biofuels},
  title        = {A systems analysis of biodiesel production from wheat straw using oleaginous yeast : process design, mass and energy balances},
  url          = {http://dx.doi.org/10.1186/s13068-016-0640-9},
  volume       = {9},
  year         = {2016},
}