Energycane produces more biodiesel than soybean at a lower cost

Date:
July 7, 2021
Source:
University of Illinois College of Agricultural, Consumer and
Environmental Sciences
Summary:
Bioenergy from crops is a sustainable alternative to fossil
fuels. New crops such as energycane can produce several times more
fuel per acre than soybeans. Yet, challenges remain in processing
the crops to extract fuel efficiently. Four new studies explore
chemical-free pretreatment methods, development of high-throughput
phenotyping methods, and commercial-scale techno-economic
feasibility of producing fuel from energycane in various scenarios.



FULL STORY ========================================================================== Bioenergy from crops is a sustainable alternative to fossil fuels. New
crops such as energycane can produce several times more fuel per acre
than soybeans.

Yet, challenges remain in processing the crops to extract fuel
efficiently.


==========================================================================
Four new studies from the University of Illinois explore chemical-free pretreatment methods, development of high-throughput phenotyping methods,
and commercial-scale techno-economic feasibility of producing fuel from energycane in various scenarios.

The studies are part of the ROGUE (Renewable Oil Generated with Ultra- productive Energycane) project at U of I. ROGUE focuses on bioengineering accumulation of triacylglycerides (TAGs) in the leaves and stems of
energycane, enabling the production of much more industrial vegetable
oil per acre than previously possible.

"The productivity of these non-food crops is very high per unit of land.

Soybean is the traditional crop used for biodiesel, but we can get higher yield, more oil, and subsequently more biofuel from lipid-producing energycane," says Vijay Singh, Founder professor in the Department of Agricultural and Biological Engineering (ABE) at U of I and co-author
on all four papers.

Biofuel production from crops involves breaking down the cellulosic
material and extracting the oil in a series of steps, explains study
co-author Deepak Kumar, assistant professor in the Chemical Engineering Department at State University of New York College of Environmental
Science and Forestry (SUNY-ESF) and adjunct research scientist at the
Carl R. Woese Institute for Genomic Biology at U of I.

"The first step is to extract the juice. That leaves bagasse,
a lignocellulosic material you can process to produce sugars and
subsequently ferment to bioethanol," Kumar says.



==========================================================================
"One of the critical things in processing any lignocellulosic biomass
is a pretreatment step. You need to break the recalcitrant structure of
the material, so enzymes can access the cellulose," he adds. "Because energycane is a relatively new crop, there are very few studies on the pretreatment and breakdown of this bagasse to produce sugars, and to
convert those sugars into biofuels." The pretreatment process also yields
some unwanted compounds, which inhibit enzymes that convert the sugar
into biofuels. The U of I researchers investigated the best pretreatment methods to maximize the breakdown while minimizing the production of inhibitors. Typically, the pretreatment process uses chemicals such as
sulfuric acid to break down the biomass at high temperature and pressure.

"We use a chemical-free method, which makes it more environmentally
friendly," Kumar explains. "Furthermore, harsh chemicals may alter
the oil structure or quality in the biomass." The researchers tested
their method using nine different combinations of temperature and time intervals. They were able to achieve more than 90% cellulose conversion
at the optimal conditions, which is equivalent to results from chemical pretreatment methods.

The second study built on those results to further investigate the
relationship between temperature, inhibitor production, and sugar
recovery.



==========================================================================
"We pretreated the lignocellulosic biomass over a range of different temperatures to optimize the condition for minimal inhibitor generation
without affecting the sugar recovery. Then we added cryogenic grinding
to the process," says Shraddha Maitra, postdoctoral research associate
in ABE and lead author on the study.

"In cryogenic grinding, you treat the bagasse with liquid nitrogen, which
makes it very brittle, so upon grinding the biomass fractures easily to
release the sugars. This further increased sugar recovery, mainly xylose,
by about 10% compared to other refining processes," Maitra explains.

Other industries use similar methods, for example for spices and essential oils, where it is important to preserve the qualities of the product. But applying them to biofuel production is new.

In a third study, Maitra and her co-authors investigated time-domain
nuclear magnetic resonance (NMR) technology to determine the stability and recovery of lipids by monitoring changes in total, bound, and free lipids
after various physical and chemical feedstock preprocessing procedures.

The research team's fourth study investigated the commercial-scale techno- economic feasibility of engineered energycane-based biorefinery. They
used computer modeling to simulate the production process under two
different scenarios to determine capital investment, production costs,
and output compared with soybean-based biodiesel.

"Although the capital investment is higher compared to soybean biodiesel, production costs are lower (66 to 90 cents per liter) than for soybean
(91 cents per liter). For the first scenario, processing energycane had
overall slightly lower profitability than soybean biodiesel, but yields
five times as much biodiesel per unit of land," says Kumar, the lead
author on the study.

"Energycane is attractive in its ability to grow across a much wider
geography of the U.S. south east than sugarcane. This is a region with
much underutilized land, yet capable of rain-fed agriculture," says ROGUE Director Steve Long, Ikenberry Endowed Chair of Plant Biology and Crop
Sciences at the University of Illinois.

"As a perennial, energycane is suitable for land that might be damaged
by annual crop cultivation. Our research shows the potential to produce
a remarkable 7.5 barrels of diesel per acre of land annually. Together
with co- products, this would be considerably more profitable than most
current land use, while having the potential to contribute greatly to
the national U.S. goal of achieving net zero greenhouse gas emissions by
2050. This proves how valuable it is to build on the successes already
achieved in bioengineering energycane to accumulate oils that are easily converted into biodiesel and biojet," Long states.

========================================================================== Story Source: Materials provided by University_of_Illinois_College_of_Agricultural,_Consumer and_Environmental_Sciences. Original written by Marianne Stein. Note:
Content may be edited for style and length.


========================================================================== Journal References:
1. Deepak Kumar, Stephen P. Long, Amit Arora, Vijay Singh.

Techno‐economic feasibility analysis of engineered
energycane‐based biorefinery co‐producing biodiesel
and ethanol. GCB Bioenergy, 2021; DOI: 10.1111/gcbb.12871
2. Shraddha Maitra, Vijay Singh. Balancing sugar recovery and inhibitor
generation during energycane processing: Coupling cryogenic grinding
with hydrothermal pretreatment at low temperatures. Bioresource
Technology, 2021; 321: 124424 DOI: 10.1016/j.biortech.2020.124424
3. Ankita Juneja, Deepak Kumar, Vijay Kumar Singh, Yadvika, Vijay
Singh.

Chemical Free Two-Step Hydrothermal Pretreatment to Improve
Sugar Yields from Energy Cane. Energies, 2020; 13 (21): 5805 DOI:
10.3390/en13215805
4. Shraddha Maitra, Bruce Dien, Stephen P. Long, Vijay
Singh. Development
and validation of time‐domain 1 H‐NMR relaxometry
correlation for high‐throughput phenotyping method for lipid
contents of lignocellulosic feedstocks. GCB Bioenergy, 2021; 13
(7): 1179 DOI: 10.1111/gcbb.12841 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210707140727.htm

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