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Department of Food, Agricultural and Biological Engineering
* Corresponding author: [email protected]
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INTRODUCTIONBiobased products industry is expected to grow from 2% in
2008 to 22% in 2025 in the global chemical industry.1 In
2014, biobased products industry added $393 billion and
created 4.2 million jobs in the U.S. economy.2
CONCLUSION AND FUTURE WORKS▪ Lignocellulosic feedstocks showed potential to be techno-
economically feasible with lower environmental impacts for LA
production when compared to corn grain and petroleum.
▪ The techno-economic and environmental feasibility can be
further improved by optimizing feedstock logistics (which can
reduce feedstock costs) and identifying microorganism strains
having high LA yield under harsh fermentation conditions.
Techno-economic and life cycle analyses of biobased
lactic acid production Ashish Manandhar and Ajay Shah*
DEPARTMENT OF FOOD, AGRICULTURAL AND BIOLOGICAL ENGINEERING
RESULTS AND DISCUSSION
Materials requirements for LA production▪ Feedstock requirements were between 1.5 kg (for corn
grain) to 2.1 kg (for corn stover) per kg of LA production
(Fig. 4).
▪ Corn grain had lowest resources requirements (Fig.4)
as it had higher sugar quantities compared to corn
stover and miscanthus.
▪ Fermentation pathway using yeast did not require LA
neutralization. Thus, lime and additional sulfuric acid for
LA neutralization and recovery were not required.
Environmental impacts - GWP
▪ Compared to petroleum-based LA, GWP reductions of
65-87% were observed for biobased LA (Fig. 6).
▪ GWP for LA production using miscanthus was lowest due
to its higher biomass yield and low input requirements.
▪ Biomass production for corn grain and stover had highest
GWP due to high machinery, fuel, and fertilizer inputs.
▪ Fermentation pathway using yeast had lowest GWP due
to reduction in chemicals required for LA neutralization.
Commercial LA production: Currently, there is only one
commercial facility producing lactic acid using first-
generation feedstock (corn grain) and non-existent for
second-generation feedstocks (corn stover and
miscanthus). Thus, there is a need to evaluate the
technical and economic feasibility, and environmental
impacts of a commercial-scale biobased LA production.
OBJECTIVE
Evaluate the technical feasibility, costs and environmental
impacts of LA production using corn grain, corn stover and
miscanthus through three fermentation pathways using
bacteria, fungi and yeast.
METHODOLOGYSystem overview
Biorefinery production capacity: 100,000 metric tons (t) of
LA per year (based on typical LA production facilities).8
System boundary: includes biomass production in the field to
LA production in the biorefinery (Fig. 3)
Functional unit: 1 kg of LA produced
Feedstocks: Corn grain, corn stover and miscanthus
Fermentation pathways: Three fermentation pathways using:
1) bacteria, 2) fungi, and 3) yeast
Techno-economic analysis (TEA)
TEA Methodology: based on literature9, as depicted in Fig. 3.
Minimum selling price (MSP): calculated based on 10%
Internal rate of return and considering byproducts (distillers
dried grains solubles for corn grain feedstock).
Analysis year: 2019
Life cycle assessment (LCA)
LCA Methodology: ISO Standard 14044-2006 10
Impact assessment method: Tool for Reduction and
Assessment of Chemicals and Other Environmental
Impacts (TRACI 2.1) – relevant for LCA studies in the U.S.11
Impact category: Global warming potential (GWP),
Eutrophication potential (EP) - Selected based on the
relative significance to the general public in Ohio.
Software: SuperPro Designer v9.5 (for process modeling and
TEA) and OpenLCA Version 1.7 (for LCA)
Data sources: Lab experiments, field data, literature,
Ecoinvent database v3.2 12, U.S. LCI database13
Figure 1. Applications of lactic acid
Market for LA is projected to
increase from $2.1 billion in
2016 to $9.8 billion in 2025.5
Figure 2. LA production from biomass using three fermentation pathways
Figure 3. Overview of the system for lactic acid production and methodology for TEA
and LCA (Note: Rectangular boxes inside the system boundary are different
processes. Inputs to different processes include machineries, equipment and
consumables. Fuel, electricity and steam are also used for different processes)
Figure 6. Global warming potential for lactic acid production
8.05-10.8 billion miles
driven by an average
passenger vehicle
SIGNIFICANCE OF WORK
While meeting current LA demand of 1.1 million t 4, compared
to petroleum-based LA, biobased LA could reduce emissions
equivalent to:
BIBLIOGRAPHY1. U.S. Department of Agriculture, 2008. www.usda.gov/oce/reports/energy/index.htm.
2. Golden et al., 2018. Indicators of the U.S. Biobased Economy. U.S. Department of Agriculture, 2018.
3. Biddy et al., 2016. Chemicals from biomass: A market assessment of bioproducts with near-term potential, NREL.
4. Wee Y, Kim J, Ryu H, 2006. Food Technol. Biotechnol. 44(2), 163–172.
5. Grand View Research, 2017. www.grandviewresearch.com/press-release/global-lactic-acid-and-poly-lactic-acid-market.5
6. Castillo Martinez et al., 2013. Trends Food Sci. Technol. 30(1), 70–83.
7. U.S. Department of Energy, 2016. Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy.
8. Adom, F.K. and Dunn, J.B., 2017. Life cycle analysis of corn‐stover‐derived polymer‐grade l‐lactic acid and ethyl lactate: greenhouse gas
emissions and fossil energy consumption. Biofuel Bioprod Bior, 11(2), 258-268.
9. Shah, A., Baral, N.R. and Manandhar, A., 2016. Technoeconomic analysis and life cycle assessment of bioenergy systems. In Advances in
Bioenergy Vol. 1, 189-247. Elsevier.
10. ISO. EN ISO 14044:2006 - Environmental Management: Life Cycle Assessment; Requirements and Guidelines.
11. U.S. Environment Protection Agency, 2012. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI)
User’s Guide.
12. Ecoinvent. Ecoinvent LCA Database, 2016. www.ecoinvent.org/database/database.html.
13. NREL, 2016. NREL USLCI Database. https://uslci.lcacommons.gov/uslci/search.
ACKNOWLEDGMENTThis study was funded in parts by USDA NIFA (Award no. 2017-67021-26141) and OARDC SEEDS (Award
no. OHOA1584)
Lactic acid (LA) is one of the few
promising chemicals identified by
U.S. Department of Energy, that
can be produced from biobased
feedstocks and used for variety
of applications (Fig. 1).3,4
LA production costs and MSP
▪ LA production costs using corn grain were lowest (Fig. 5).
▪ Yeast-based production pathway did not require LA
neutralization during fermentation, and thus, had lower
production costs for all feedstocks.
▪ MSP of LA produced corn grain were lower than
production costs due to additional revenue from
byproduct (distillers dried grain solubles).
▪ MSP of biobased LA were within the range of LA prices in
the market.
Figure 5. Lactic acid production costs and minimum selling prices
LA production routes: LA can be produced from
petrochemical and biochemical routes.6
Biochemical route uses renewable biomass sources (Fig. 2).
Corn grain (main starch-based first-generation feedstock in
the U.S.), and lignocellulosic feedstocks (second-generation
feedstock) such as corn stover (residues of corn plant) and
miscanthus (energy crop) have great potential as
feedstocks for biobased industries.7
LA can be produced via three fermentation pathways using
either 1) bacteria, 2) fungi or 3) yeast as fermenting
microorganism, which determines the processes (Fig. 2).
Note: Material flows provided in kg
Environmental impacts - EP
▪ Compared to petroleum-based LA, EP reductions of 65-
72% were observed for biobased LA (Fig. 7).
▪ Biomass production and LA conversion had highest
contribution to EP due to fertilizer and chemical use.
Figure 7. Eutrophication potential for lactic acid production
40,900-44,900 t phosphorus (P)
~ 13 × Total annual P loading
from Maumee, Sandusky and
Cuyahoga rivers to Lake Erie
Figure 4. Feedstock, material and utilities requirements for lactic acid
production. (Note: The green, blue and black numbers represent
fermentation pathways using bacteria, fungi and yeast, respectively)
