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Plastic from food waste

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Plastic waste management is a complicated business.  Most methods of recycling or breaking down plastic are costly and harmful to the environment.  The most common biodegradable alternatives – like paper straws – are less than ideal replacements.

There are many approaches to creating biodegradable plastics using feedstocks like seaweed, sugarcane, and other plant matter.  However, the resulting plastics often fall short compared with conventional petroleum-based plastics.

One type of bioplastic that is gaining popularity is polyhydroxyalkanoates, or PHA.  PHA is a plastic produced by microorganisms.  It is fully compostable or biodegradable but in other ways but looks, feels, and functions like regular plastic but without the environmental drawbacks.

PHA can be made using bacterial fermentation of a variety of feedstocks such as vegetable oils, sugars, starches, and even methane and wastewater.

Researchers at a startup from the University of Waterloo in Canada called MetaCycler BioInnovations have developed a process for producing PHA based on bacteria that has been engineered to convert waste from milk and cheese production.  This solution upcycles waste from the dairy industry into cost-effective, sustainable bio-based plastics. 

PHAs can be tailored to have a wide range of properties ranging from being rigid and tough to being quite flexible.  Therefore, they can be suitable for many applications including packaging, agricultural films, and consumer goods. 

The Waterloo technology is a way to tackle the problems of both food waste and plastic pollution with one solution.

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Turning food waste into a new bioplastic

Photo, posted December 10, 2017, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing carbon in buildings

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According to a new study by researchers at the University of California, Davis and Stanford University, construction materials used in buildings have the potential to lock away billions of tons of carbon dioxide.  The study, published in Science, shows that storing CO2 in buildings could be a major contributor to efforts to reduce greenhouse gas emissions.

Overall efforts in carbon sequestration take carbon dioxide – either as it’s being produced or once it’s already in the atmosphere – and store it away.  Storing it might involve injecting it into underground caverns or deep in the ocean.  Alternatively, storing it might involve converting it into a stable form using chemical reactions.  These various strategies involve both practical challenges and potential environmental risks.

The new study suggests that many materials that are already produced in large quantities have the potential to store carbon dioxide.  These include concrete, asphalt, plastics, wood, and brick.  More than 30 billion tons of these materials are produced worldwide every year.

Ways to accomplish carbon storage include adding biochar into concrete, using artificial rocks loaded with carbon as concrete and asphalt aggregates, plastic and asphalt binders based on biomass instead of petroleum, and including biomass fiber into bricks. 

The largest potential is using carbonated aggregates to make concrete.  Concrete is by far the world’s most popular building material with more than 20 billion tons being produced each year.

The feedstocks for these ways to store carbon in building materials are mostly low-value waste materials, so the economics of implementing these carbon sequestering strategies are likely to be quite favorable.

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Storing Carbon in Buildings Could Help Address Climate Change

Photo, posted October 19, 2022, courtesy of Alexandre Prevot via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Where do states get their electricity?

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How the United States produces its electricity has changed dramatically over the past few decades.  Coal used to be the dominant source of power in this country, but natural gas surpassed it in 2016, and coal’s share has been shrinking ever since.  Fossil fuel still generates the majority of America’s electricity, but renewable power is increasing its contribution all the time.

On a state-by-state basis, there are very large variations in the mix of power sources.  Ten states still get their largest amount of power from coal, but this is down from 32 states in 2001.  Four states have hydroelectric power as their largest source, including Vermont which gets more than half of its power that way. 

Texas produces more electricity than any other state by a wide margin.  It’s not just because it has a large population. It is because it uses huge amounts of power to refine petroleum products.  Coal produces only 13% of Texas’ electricity and the state is by far the country’s largest producer of wind power.

New York gets nearly half of its power from natural gas, 21% from hydroelectric power, and 21% from nuclear power.  Wind and solar power are still small, but both are growing in the state.

When people try to assess the climate impact of driving electric cars, based on the origins of the electricity they use to power the car, the results can vary dramatically based on what state they live in.  Nationwide, electricity is getting cleaner and greener, but the process is by no means uniform across the country.

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How Does Your State Make Electricity?

Photo, posted March 17, 2021, courtesy of Bureau of Reclamation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biofuel refineries and toxic pollution

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There have been decades of government support for renewable, crop-based fuels – primarily corn ethanol.  In fact, it is a required component of gasoline sold in this country.  The biofuels industry has long claimed ethanol to be a clean, greener alternative to petroleum. 

There have been arguments all along that the environmental benefits of corn ethanol are dubious at best because of the energy required to produce the stuff.  There are also issues related to burning a food crop instead of feeding it to people and that the conversion of grasslands and forests to produce it releases massive amounts of carbon.

Recently, another serious concern has emerged.  A new review of industry data has found that the country’s biofuel refineries, mostly located in the Midwest, produce large amounts of toxic air pollutants, in some cases ever more than from their petroleum counterparts.

Emissions data from the country’s 275 ethanol, biodiesel, and renewable diesel plants revealed that they release carcinogenic formaldehyde as well as other potentially dangerous substances including acetaldehyde, hexane, and acrolein.  In 2022, biofuel refineries released 12.9 million pounds of hazardous air pollutants, compared to 14.9 million pounds emitted by oil refineries, and the biofuel plants actually emitted more of the four chemicals just mentioned than petroleum refineries did.

The broad use of crop ethanol is the result of intensive industry lobbying.  Ethanol plants are even exempt from some air pollution permitting requirements.  Perhaps the time has come to revisit its pervasive and mandated use.

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Biofuel Refineries Are Releasing Toxic Air Pollutants in Farm Communities Across the US

Photo, posted February 27, 2021, courtesy of Sue Thompson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biodegradable microplastics

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Ordinary plastics are not biodegradable, but they are also not indestructible.  Plastics in the environment can break down into tiny fragments – microplastics – and those, unfortunately, are nearly indestructible.  Microplastics have been documented in the oceans and in soil virtually everywhere on Earth including remote frozen wastelands and on top of high mountains.  More recently, they have been found in our own arteries, lungs, and even in placentas.  Microplastic pollution is a very serious problem.

There is considerable ongoing effort to develop biodegradable plastics from non-petroleum sources.  There has been progress but it has not necessarily been aimed at creating bioplastics that do not create microplastic when they break down.

Researchers at the University of California San Diego have developed algae-based polymers that they have shown to degrade when composted.  Recently, in work published in the journal Nature Scientific Reports, they have shown that even fine microparticles of their bioplastic are digested by microbes when placed in a compost.  What remains are the starting plant materials from which the plastic was made.  Products made from this sort of plastic would not only be sustainable beyond their useful lifetime but would also not represent a potential danger to human life.

Creating this eco-friendly alternative to petroleum-based plastic is only the first step toward creating a viable replacement for existing plastics.  It is necessary to be able to use the new material on existing manufacturing equipment and for it to have the same mechanical and thermal properties as the materials it is replacing.  But the researchers are optimistic that this could be a potential solution to an increasingly serious problem.

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Say Hello to Biodegradable Microplastics

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bio-based products on the rise

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There is a growing global movement working towards replacing conventional synthetic products – ones that are toxic to make or use, difficult to recycle, and have large carbon footprints – with products made from plants, trees, or fungi that can be safely returned to the earth at the end of their useful life.  This so-called bioeconomy is in its infant stages, but there is increasing interest in turning successful research into manufactured products.

One example is nylon.  Nylon was created in the 1930s by DuPont.  It has been used and continues to be used in a wide range of products.  The problem with it is that it is made from petroleum, it doesn’t biodegrade, and producing it generates nitrous oxide, which is a problematic greenhouse gas.

A San Diego-based company called Genomatica has developed a plant-based nylon using biosynthesis, a process in which a genetically engineered microorganism ferments plant sugars to create a chemical intermediate that can be turned into the nylon-6 polymer, and then into textiles. 

The impetus for developing bio-based products includes the growing public disgust at the mounting environmental toll of plastic, not the least of which is that people and animals are increasingly ingesting it.  Coupled with this, there is a rapidly-growing torrent of funding, especially in the US and Europe, aimed at accelerating the transition away from products that are non-biodegradable, toxic, and that produce carbon emissions.   Last September saw the launch of the National Biotechnology and Biomanufacturing Initiative which will support research and development on such topics as the use of sustainable biomass and waste resources to make non-toxic, bio-based fuels, chemicals, and fertilizers.

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From Lab to Market: Bio-Based Products Are Gaining Momentum

Photo, posted May 27, 2010, courtesy of André C via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ending plastic separation anxiety

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Petroleum-based plastics are one of the biggest environmental problems we face.  They mostly end up in landfills – or worse, in the oceans and elsewhere in the environment – and they basically don’t decompose over time.  Bio-based plastics were invented to help solve the plastic waste crisis.  These materials do break down in the environment providing a potential solution to the problem.  But it turns out that they can actually make plastic waste management even more challenging.

The problem is that bioplastics look and feel so similar to conventional plastics that they get mixed in with the petroleum-based plastics rather than ending up in composters, where they can break down as designed.

Mixtures of conventional and bioplastics end up in recycling streams where they get shredded and melted down, resulting in materials that are of very poor quality for making functional products.  The only solution is to try to separate the different plastics at recycling facilities, which is difficult and expensive to do.

Scientists at Lawrence Berkeley National Laboratory, the Joint BioEnergy Institute, and the incubator company X have invented a simple “one pot” process to break down mixtures of different types of plastic using naturally derived salt solutions and specialized microbes and then produce a new type of biodegradable polymer that can be made into fresh commodity products.

The team is experimenting with various catalysts to find the optimum way to break down polymers at the lowest cost and are modeling how their processes can work at the large scales of real-world recycling facilities. Chemical recycling of plastics is a hot topic but has been difficult to make happen economically at the commercial scale.

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Putting an End to Plastic Separation Anxiety

Photo, posted November 28, 2016, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pollution From Tires | Earth Wise

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A few years ago, researchers investigating massive deaths of coho salmon in West Coast streams discovered that the water contained particles from vehicle tires.  The cause of the fish mortality turned out to be a chemical called 6PPD that is added to tires to prevent cracking and degradation.  The mystery was solved, but so far, the chemical continues to be used by all major tire manufacturers and is found on roads and in waterways around the world.

Worse still, the acute toxicity of 6PPD and the chemicals that it transforms into when exposed to ground-level ozone is only the tip of the tire pollution iceberg.  Tire rubber contains more than 400 chemicals and compounds, many of which are carcinogenic. 

About 2 billion tires are sold across the globe each year and that number is expected to reach 3.4 billion by 2030.  Tires are made from about 20% natural rubber and 24% synthetic rubber, which requires about 4 gallons of petroleum per tire.  Hundreds of other ingredients – including steel, fillers, heavy metals like copper, cadmium, lead, and zinc – make up the rest.

Tire wear particles are emitted continually as vehicles travel.  They range in size from visible pieces of rubber or plastic to microparticles.  Research has shown that a car’s four tires collectively emit half a trillion ultrafine particles per mile driven.  These particles are small enough to be breathed into the lungs and can travel throughout the body and even cross the blood-brain barrier.  Particle pollution from tires exceeds that from tailpipes.

Tire pollution is a huge problem that is just starting to receive the attention it deserves.

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Road Hazard: Evidence Mounts on Toxic Pollution from Tires

Photo, posted June 22, 2018, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better Plastic Recycling | Earth Wise

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Many of us are careful to put our plastic trash into the appropriate recycling bins hoping that we are helping to stem the global tide of plastic waste.  But many plastics are not recyclable at all and recycling those that are is not even always a good thing.  Breaking down plastics can generate polluting microplastics that are themselves a major environmental problem.  And perhaps the biggest problem for recycling efforts is that they are not cost effective and generally incur huge losses.

Chemical engineers at the University of Wisconsin-Madison recently published a study in the journal Nature outlining a new technique for turning low-value waste plastic into high-value industrial chemicals. 

The technique makes use of two existing chemical processing techniques.  The first is pyrolysis, which is high-temperature heating in an oxygen-free environment.  Heating waste plastic in this way produces pyrolysis oil, a liquid mix of various compounds that includes large amounts of olefins.  Olefins are simple hydrocarbons that are a central building block of many chemicals and polymers.  Olefins are most often produced by energy-intensive processes like steam cracking of petroleum. 

The UW-Madison process takes the olefins and subjects them to a process called homogenous hydroformylation catalysis, which converts them into aldehydes, which can then be further reduced into important industrial chemicals. 

The payoff is that the process can take waste plastics, which are only worth about $100 a ton, and turn them into high-value chemicals worth $1,200-$6,000 a ton.  If the process can be optimized and otherwise made ready for industrial-scale use, it would be a real game-changer in the battle against plastic waste.

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New recycling process could find markets for ‘junk’ plastic waste

Photo, posted September 16, 2015, courtesy of Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Big Oil And Big Lithium | Earth Wise

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The world’s big oil companies have worked pretty hard to prolong society’s dependence on petroleum.  When there are trillions of dollars at stake, there is plenty of motivation.  But those companies do see the writing on the wall.

An Exxon Mobil-funded study last year estimated that light-duty vehicle demand for combustion engine fuels could peak in 2025 and that electric vehicles of various types could grow to more than 50% of new car sales by 2050.  This is pretty pessimistic compared with most other surveys, but it is still a big number.  Exxon also projected that the global fleet of EVs could reach 420 million by 2040.

As a result of all this, Exxon is preparing for a future far less dependent on gasoline by drilling for lithium rather than oil.  The company recently purchased mining rights to a sizable chunk of Arkansas land for over $100 million from which it aims to produce lithium for electric car batteries.

Exxon’s consultants estimated that the 120,000 acres in the Smackover formation of southern Arkansas could have as much as 4 million tons of lithium carbonate, enough to power 50 million cars and trucks. 

Exxon plans to spend $17 billion through 2027 on cutting carbon emissions and developing low carbon technologies.  Other large oil producers have also been looking at the lithium business.  At the same time, some large oil companies like BP and Shell are investing in renewable energy.

The prospect of EVs dominating transportation in the coming decades is a strong incentive for oil-and-gas companies to adapt their businesses to the new world.

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Exxon Joins Hunt for Lithium in Bet on EV Boom

Photo, posted August 16, 2014, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Liquid Fuel From Sunshine | Earth Wise

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A key goal of artificial photosynthesis research is to be able to produce a useful liquid fuel using only carbon dioxide, water, and sunlight in a single step.  Such a so-called solar fuel would produce net zero carbon emissions and would be completely renewable.

Bioethanol has long been touted as a green alternative to fossil fuels, since it is made from plants rather than petroleum.  But producing it takes up agricultural land that could be used to grow food instead and there are emissions associated with many aspects of the process by which plant mass becomes fuel.

Researchers from the University of Cambridge in the UK have developed a so-called artificial leaf that produces ethanol or propanol – usable liquid fuels – in a single step.  They developed a copper and palladium-based catalyst that allows the artificial leaf to directly produce multicarbon complex chemicals.  Earlier versions of artificial leaves could make simple chemicals, such as syngas, which would then require additional processing to turn into high-density fuels.

The new device produces liquid fuel from carbon dioxide and water simply by shining sunlight on it.

At present, the artificial leaf is a proof-of-concept device that exhibits only modest efficiency.  The researchers are working to optimize the device’s light absorbers so that they can better make use of sunlight and to optimize the catalyst so that it can convert more of the sunlight into fuel.  In addition, the device needs to be scaled up so that it can produce large volumes of fuel.

All that being said, it is an important step towards people being able to do what plants have been doing for millions of years.

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Driving on sunshine: clean, usable liquid fuels made from solar power

Photo, posted March 23, 2015, courtesy of Astro via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geothermal Energy Storage | Earth Wise

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About 12% of the energy consumed by humanity is used to heat and cool homes and businesses.  A study by researchers at Lawrence Berkeley National Laboratory and Princeton University looked at a novel approach to making use of underground water to maintain comfortable temperatures and reduce consumption of natural gas and electricity.

The idea is to use aquifer thermal energy storage (known as ATES) to provide both heat in the winter and cooling in the summer.  The concept leverages the heat-absorbing property of water and natural geological features.  The idea is to pump up water from existing underground reservoirs and heat it at the surface using environmental heat or even excess energy from solar or wind generation.  Then the warm water is pumped back down. It stays warm for a long time – even months – because the earth is a good insulator.  When the water is pumped back up in the winter, it is much hotter than the ambient air and can be used to supply heat to buildings.

Alternately, water can be pumped up and cooled in the winter and then put back down underground and stored until cooling is needed in the summer months.

This technology has not been used much in the US, but it is gaining recognition internationally, particularly in the Netherlands.  It can perform very well in areas with large seasonal fluctuations.

The research study used modeling and various simulations to estimate how much energy ATES could save on the US grid.  The results showed that adding ATES to the grid could reduce consumption of petroleum products for heating and  cooling by up to 40%.  The system could also help prevent blackouts by reducing high power demand during extreme weather events.

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Underground Water Could be the Solution to Green Heating and Cooling

Photo, posted February 19, 2012, courtesy of Sanjay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic From Sunlight | Earth Wise

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Photosynthesis is the process that plants use to turn water, carbon dioxide, and energy from sunlight into plant biomass.  It provides humans and much of animal life with food.  Photosynthesis is also nature’s way of reducing the amount of carbon dioxide in the atmosphere.  The CO2 is not directly stored in plants but rather is combined into organic compounds.

Researchers across the globe are trying to find effective ways to mimic photosynthesis.  One version of artificial photosynthesis seeks to take carbon dioxide and combine it into organic compounds that can be used as raw materials for various kinds of manufacturing. 

A research team in Japan has found a way to synthesize fumaric acid from carbon dioxide using sunlight to power the process.  Fumaric acid is a chemical typically synthesized from petroleum and is used as a raw material for making biodegradable plastics such as polybutylene succinate. 

Much of artificial photosynthesis research is aimed at using solar energy to convert carbon dioxide directly into a fuel rather than a raw material.  Such solar fuels can be produced by a variety of means including thermochemical (using the sun’s heat to drive chemical reactions), photochemical (using the sun’s light to drive chemical reactions), and electrochemical (using solar-generated electricity to drive chemical reactions.)   These approaches generally involve the use of specialized catalysts to drive the desired chemical reactions. 

One way or another, what techniques for artificial photosynthesis have in common is trying to imitate what plant life on Earth has been doing for millions of years. 

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Artificial photosynthesis uses sunlight to make biodegradable plastic

Photo, posted June 14, 2017, courtesy of Alex Holyake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better Ways To Make Bioplastics | Earth Wise

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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.

Is Peak Oil Here? | Earth Wise

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For many years there has been talk of “peak oil”, the point at which rising world oil consumption would peak and then start declining.  Some analysts have been predicting that this could happen by the 2030s.   But the coronavirus pandemic drove a 9% slump in oil demand in 2020 that some economists are saying might never be entirely reversed.

There are three major forces driving down the world’s appetite for oil:  decarbonization of economies to meet the goals of the Paris climate agreement, declining demand for oil as renewable energy sources and electric vehicles are increasingly adopted, and detoxification as cities act to curb particulates and emissions from burning petroleum.

The largest single factor is electric vehicles.  Automobiles currently consume almost half of the world’s oil.  As of the end of 2020, there were an estimated 10 million electric cars as well as more than 600,000 electric buses and trucks.  This is still less than 1% of all vehicles, but 5% of all new cars being bought are now electric and the number is growing rapidly.  Experts estimate that nearly a quarter of global car sales will be electric vehicles by 2025 and many car manufacturers are promising to sell only electric cars within the next 10 years.

The decline in oil demand is pretty much inevitable at this point.  The main question is how quickly it will happen.  Road transport makes up 48% of global oil demand, petrochemicals account for 14%, aviation 7%, and shipping 6%.  Ultimately all these things are likely to diminish over time. 

Only time will tell, but the long-awaited arrival of peak oil may already have happened.

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Amid Troubles for Fossil Fuels, Has the Era of ‘Peak Oil’ Arrived?

Photo, posted April 14, 2019, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Transparent Wood | Earth Wise

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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.

Replacing Plastic Tableware | Earth Wise

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Plastics have been described as the “ubiquitous workhorse material of the modern economy.”  But their versatility, pliability, and durability comes at a heavy price to the environment.  Plastic pollution is quite literally everywhere.  Plastic debris and microplastic particles can be found in every corner of the globe, including the Arctic and Antarctic. 

The scourge of plastic pollution is driving scientists to create ecologically-friendly alternatives.  According to a paper recently published in the journal Matter, scientists have developed “green” tableware made from sugarcane and bamboo that doesn’t sacrifice on convenience or functionality.  This eco-friendly tableware could serve as a permanent replacement for plastic cups and other disposable plastic containers. 

Traditional plastic polymers, a product of petroleum, can take as long as 1,000 years to decompose in landfills.  The new material only takes 60 days to break down.

To create this material, scientists used bamboo and bagasse, also known as sugarcane pulp.  Bagasse is one of the largest food-industry waste products.  The researchers wound the fibers together to form a mechanically stable and biodegradable material.  They added an alkyl ketene dimer, an eco-friendly chemical, to increase the oil and water resistance of the material.  The green material is durable enough to hold liquids like hot coffee and hot greasy foods like pizza.   

There’s another advantage: the green material’s manufacturing process emits 97% less CO2 than the process to make commercial plastic containers.  The next step is to lower the manufacturing cost.  While the cost of cups made from the green material is $2,333 per ton, traditional cups made from plastic are still slightly cheaper at $2,177 per ton.

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This tableware made from sugarcane and bamboo breaks down in 60 days

Photo, posted May 19, 2013, courtesy of Henry Burrows via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plastic From Algae | Earth Wise

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Many researchers consider algae to be one of the best renewable resources for replacing fossil fuels and even as a food source.  The green microalgae Nannochloropsis salina is already a common source of omega-3 fatty acids that are sold as dietary supplements.  As a result, that algae strain is already grown on a large scale for the production of omega-3 products.

A group of researchers at UC San Diego has developed a way to make use of the waste stream from that production to create plastics and other useful products.  Currently, when the algae is processed to extract the omega-3 oil, leftover oils comprising more than 70% of the starting material are either thrown away or burned. 

The UCSD team has developed a process to purify and convert this waste stream into azelaic acid, which is a building block for flexible polyurethanes.   These materials have all kinds of commercial applications from flip-flops and running shoe soles to mattresses and yoga mats.

By analogy to the use of animals by native American tribes, the researchers wanted to “use the whole buffalo” in their solution for algae processing waste and therefore figured out how to convert heptanoic acid – another substance in the algae waste stream – into a food flavoring and fragrance.  The flavoring molecule is valued at over $500 per kilogram.

The work, published in the journal Green Chemistry, demonstrates that an algae-source waste stream has both the practical and economic potential to support production of polyurethanes.  The team is already working with shoe companies to commercialize the technology.  With mounting concern over petroleum-based plastic waste, renewable plastic made from algae is an attractive alternative.

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Researchers Turn Algae Leftovers into Renewable Products with Flare

Photo, posted November 8, 2006, courtesy of Adam Moore via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plants Paying For Biofuels | Earth Wise

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Biofuels are an important element in broader strategies to replace petroleum in transportation fuels like gasoline, diesel, and jet fuel.  The idea is that biofuels recycle carbon by getting it from growing plants rather than from fossil sources.  The biggest problem with biofuels is that they cost more than conventional petroleum fuels, so there is economic incentive to keep burning the fossil fuels.

One strategy to make biofuels cost competitive is to have the plants provide additional economic benefits beyond being a feedstock for fuel.  This in principle can be done by engineering plants to produce valuable chemical compounds, or bioproducts, as they grow.  Bioproducts include such things as flavoring agents and fragrances as well as biodegradable plastic.  These bioproducts can be extracted from the plants and then the remaining plant material can be converted to fuel. 

Researchers at Lawrence Berkeley National Laboratory recently published a study to determine what quantities of bioproducts plants need to produce to result in cost-effective biofuel production.

The study looked at a compound called limonene, which is used for flavoring and fragrance.  They calculated that if this compound was accumulated at 0.6% of the biomass dry weight, it would offer net economic benefits to biorefineries.  This corresponds to recovering 130 pounds of limonene from 10 tons of sorghum on an acre of land.

Such quantities are completely practical but, on the other hand, none of these substances are needed in huge quantities. Just six refineries could supply the world with limonene.  So, fuel crops would need to be engineered to produce a broad range of bioproducts to enable a viable cost-effective biofuel industry.

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Making Biofuels Cheaper by Putting Plants to Work

Photo, posted September 28, 2019, courtesy of Michele Dorsey Walfred via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Plastic Pollution On The Way | Earth Wise

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Public concern about plastic pollution has been rising.  More and more of us are choosing reusable grocery bags, metal straws, and reusable water bottles.  We shake our heads at images of immense plastic garbage patches in the ocean. We see reports of birds with 15% of their body weight in plastic.

While all of this is going on, companies like ExxonMobil, Shell, and Saudi Aramco are ramping up production of plastic – which is mostly made from oil, gas, and their byproducts.  They are doing this as a hedge against the growing possibility that the global response to climate change will reduce demand for their fuels.  Plastics are part of the category called petrochemicals, which currently account for 14% of oil use.  Petrochemicals are expected to drive half of oil demand growth over the next 30 years.

The World Economic Forum predicts plastic production will double in the next 20 years.  The fracking boom in the United States has turned this country into a big growth area for plastic production.  Natural gas prices are low which is hurting profits at fracking operations.  But fracking also unearths ethane, which is a feedstock for plastic production.  So plastic is becoming a kind of subsidy for fracking.

The American petroleum industry’s hub has historically been the Gulf Coast of Texas and Louisiana as well as a stretch along the lower Mississippi River.  There is a slew of new projects there.  The industry is also seeking to create a new plastics corridor in Ohio, Pennsylvania, and West Virginia, where fracking wells are rich in ethane.

Society in general may be increasingly concerned about the impact of things like carbon emissions and plastic pollution, but the fossil fuel industry continues to focus entirely on growth and profits.

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The Plastics Pipeline: A Surge of New Production Is on the Way

Photo, posted January 10, 2015 , courtesy of Daniel Orth via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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