lignin

Better Ways To Make Bioplastics | Earth Wise

August 27, 2021 By EarthWise Leave a Comment

The world produces over 300 million tons of plastics each year, mostly produced from petroleum. The environmental consequences are substantial and there is a critical need to replace as much of that plastic production with biodegradable plastics as possible. Thus, there is global research aimed at making bioplastics more economical and as environmentally friendly as possible.

Researchers at Texas A&M University have developed an improved approach for making bioplastics from corn stubble, grasses, and mesquite agricultural production. Apart from the obvious environmental benefits of having biodegradable plastics, producing bioplastics from common agricultural waste would create new revenue streams for farmers as well as the people who transport harvested feedstock and byproduct crops to refinery operations.

The key to bioplastic production is the efficient extraction and use of lignin, the organic polymer that is the primary structural support material in most plants. The new research takes five conventional pretreatment technologies for plant materials and modifies them to produce both biofuel and plastics together at a lower cost. The new method is called “plug-in preconditioning processes of lignin” and it can be directly and economically added into current biorefineries. The process is designed to integrate dissolving, conditioning, and fermenting lignin, extracting energy from it and making it easily adaptable to biorefinery designs.

The so-called bioeconomy currently supports some 286,000 jobs. Innovation is the key to achieving more widespread use of biodegradable plastic. With improved economics of so-called lignocellulosic biorefineries, there can be new avenues to use agricultural waste to produce biodegradable plastics.

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‘Plugging in’ to produce environmentally friendly bioplastics

Photo, posted November 5, 2015, courtesy of Kathryn Faith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Transparent Wood | Earth Wise

June 14, 2021 By EarthWise Leave a Comment

In recent years, there have been efforts to change the nature of wood to give it new properties. People have demonstrated so-called augmented wood with integrated electronics, energy storage capabilities, and other properties. Several different groups of researchers have developed wood that is actually transparent.

In 2016, researchers at KTH Royal Institute of Technology in Stockholm demonstrated transparent wood made by selectively extracting lignin – the substance that makes up the cell walls of wood -and replacing it with a polymer. The result is a new material that is weatherproof, fairly fire resistant, stronger than wood, lighter than wood, and transparent.

When the lignin is removed from wood, the empty pores left behind need to be filled with something that restores the wood’s strength. The early versions of transparent wood used polymethyl methacrylate – essentially acrylic plastic – for this purpose. But that material is made from petroleum, so it is not an environmentally desirable approach.

Recently, the KTH researchers have successfully tested an eco-friendly alternative: limonene acrylate, which is a monomer made from renewable citrus, such as peel waste that can be recycled from the orange juice industry.

There are many potential applications for transparent wood as a structural material. These include load-bearing windows, skylights, and semi-transparent facades that are strong and thermally insulating and yet permit light to enter.

Transparent wood would be a very attractive material for many applications in that it comes from renewable sources and offers excellent mechanical properties including strength, toughness, low density, and low thermal conductivity.

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Citrus derivative makes transparent wood 100 percent renewable

Photo, posted October 12, 2018, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fuel From Lignin | Earth Wise

November 26, 2020 By EarthWise Leave a Comment

Lignin is an organic polymer that provides the rigid structure of plants and is what gives wood and bark their characteristic properties. Lignin typically comprises between 20 and 35% of the mass of wood. The two major substances extracted from trees, grasses, and other biomass materials are cellulose and lignin. Cellulose is used to make paper, bioethanol, and other products, but lignin is largely unused because it is difficult to break down into useful substances such as feedstocks for fuels. As a result, lignin is largely wasted. Worldwide, some 50 million tons of lignin are produced from paper and bioethanol manufacturing each year and almost all of that is simply burned to generate heat.

Lignin can be broken down using pyrolysis techniques at high temperatures to create bio-oils, but those oils lack sufficient hydrogen and contain too much oxygen to be useful as fuels. There is a process called hydrodeoxygenation that adds hydrogen and removes oxygen, but it requires high temperatures and very high pressures as well as producing char and tar that reduces the efficiency of the process.

Researchers at Georgia Tech recently published work describing a new process for turning lignin into useful products. They developed a dual catalyst system of super-acid and platinum particles that adds hydrogen and removes oxygen from lignin bio-oil and makes it useful as a fuel and source of chemical feedstocks.

The new process could help meet the growing demand for bio-based oils as well as helping the forest product, paper, and bioethanol industries by providing an additional revenue stream from what previously was a waste product.

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New Process Boosts Lignin Bio-oil as a Next-Generation Fuel

Photo, posted August 16, 2017, courtesy of evcabartakova via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plant-Based Jet Fuels

May 9, 2019 By EarthWise Leave a Comment

The global aviation industry uses a whole lot of fuel: more than 5 million barrels a day. It is an incredibly energy-intensive industry and almost all of its energy comes from petroleum-based fuels.

While other large energy sectors such as electric power, ground transportation and commercial buildings have well-defined pathways to adopting renewable energy sources, the aviation industry does not have such a straightforward way to make a transition to sustainability. Electrifying planes using batteries or fuel cells is very challenging for a number of reasons, notably the weight restrictions on aircraft. So liquid biofuels as replacements for petroleum-based fuels remain the most promising approach.

A new study at the Lawrence Berkeley National Laboratory concludes that sustainable plant-based biofuels could provide a competitive alternative to conventional petroleum fuels if current development and scale-up initiatives are successful.

Multidisciplinary teams based at the Department of Energy’s Joint BioEnergy Institute are focused on optimizing each stage of the bio-jet fuel production process. This includes bioengineering ideal source plants and developing methods for efficiently isolating the carbohydrates in non-food biomass that bacteria can digest and bioconvert into fuel molecules.

The critical issue is cost. The theoretical cost of bio-jet fuel has come down dramatically in recent years but is still around $16 a gallon. The cost of standard jet fuel is about $2.50 a gallon. So, the real challenge is bridging that gap.

Reducing the cost of the fuel could come both from the material and process improvements that are underway as well as by finding ways to turn the leftover lignin residuals from the bioconversion process into valuable chemicals.

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Bright Skies for Plant-Based Jet Fuels

Photo, posted March 28, 2009, courtesy of Yasuhiro Chatani via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Biofuel Waste Into Valuable Chemicals

December 20, 2017 By EarthWise Leave a Comment

When biofuels are made, tough plant material is left over as waste. The material is lignin, which is a main component of plant cell walls that gives plants their structural integrity. Lignin is made up of many valuable compounds, but taking it apart to extract them is very difficult.

Making Biofuel Cost Effective

June 14, 2017 By EarthWise

Biofuels are considered to be a sustainable alternative to fossil fuels. However, they are generally more expensive than competing fossil fuels. Government subsidies, such as we have for ethanol in this country, have been necessary to make biofuels competitive in the marketplace.