Domestic Next-Gen Feedstocks: Revolutionizing the Bioeconomy (Part 1 of 2)

By Jennifer Kaplan

Imagine a bioeconomy where sustainability is a fundamental prerequisite. While we have made much progress on bioeconomy technology, the challenges of developing verifiably “sustainable” feedstock remains a challenge. The fact remains that to achieve the promise of a lower carbon bioeconomy, we will have to harness the potential of agricultural byproducts as next-gen feedstocks. Once this can be done, we can reduce waste and create new value chains and economic opportunities across the country. The key to unlocking this potential lies in strategically matching feedstocks to appropriate applications based on their unique compositional profiles and processing requirements. This approach ensures optimal utilization of resources and maximizes the economic and environmental benefits of the bioeconomy. By investing in the development of next-gen agricultural feedstocks, we can drive innovation, create jobs, and build a more sustainable future for all.

Unlocking the Potential of Domestic Agricultural Residues

Here in the United States, the agricultural industry is sitting on a true cornucopia of opportunity. A 2023 Department of Energy report projects annual agricultural residue production could reach 205 million dry tons by 2030—primarily from corn stover, wheat straw, and residues from barley, oats, and sorghum. Primary crop residues offer a consistent, large-scale supply of raw materials for various industries. However, an emerging opportunity lies in exploiting significant volumes of biomass from sources beyond these primary crop residues. Domestic residues and processing wastes from other crops—such as nutshells and rice hulls—while less abundant, offer significant opportunities for smaller-scale and specialized applications. These materials are particularly suited for precision fermentation, production of niche biochemicals and nutraceuticals, and supporting localized biorefining operations.

Policy and Incentives: Driving Adoption of Next-Gen Feedstocks

Policy frameworks and incentives are significantly influencing the development and adoption of next-gen feedstocks. The good news is that several mechanisms are currently in play, supporting this trend:

1. Renewable Fuel Standards (RFS): In the US, the RFS program mandates the use of renewable fuels, creating a market for biofuels derived from next-gen feedstocks.
2. Carbon Pricing: While the US lacks a national carbon pricing system, some states and regions have implemented carbon pricing mechanisms. These local efforts, along with other climate policies, are beginning to influence the competitiveness of bio-based alternatives relative to fossil-based products in certain markets.
3. Research Grants and Tax Incentives: The US government and private foundations are providing substantial funding for research into next-gen feedstock applications.

Additionally, Tax incentives and credits for companies investing in bio-based technologies and products can still be found. These incentives, part of ongoing efforts to promote renewable energy and sustainable materials, include programs like the RFS and extensions through recent legislation such as the Inflation Reduction Act. While specific details may change, the overall trend of government support for the bio-based sector persists, encouraging innovation and investment in sustainable technologies.

These policy tools play a crucial role in overcoming the economic challenges often associated with new technologies and in accelerating the transition to a bio-based economy.

Beyond Corn Stover: The Diversity of Next-Gen Feedstocks

For years, the bioeconomy has focused on well-known feedstocks like corn stover and wheat straw. While unlocking the potential of primary crop residues remain essential for large-scale biofuel production due to their abundance, challenges in their widespread adoption persist. To complement this established research, a range of feedstocks is emerging from diverse agricultural waste streams, offering potential for specialized and small-scale biofuel applications. These novel sources, which may require less pre-treatment, are particularly promising for new technologies, especially those that require smaller volumes of feedstock. The development of next-gen feedstocks from agricultural residues will allow entrepreneurs and innovators to tap into less abundant but potentially more specialized feestocks, opening up new possibilities in the bioeconomy. 

The world of next-gen feedstocks is incredibly diverse, with different bioeconomy applications requiring feedstocks with varying compositional profiles. Let’s explore this diversity of non-primary residues:

1. High-Sugar Feedstocks:

• Sugar beet pulp
• Fruit processing wastes (e.g., apple, cranberry, citrus peels)
• Cereal processing residues
• Molasses

These are ideal for fermentation processes, producing biofuels, organic acids, and other platform chemicals.

2. Lignocellulosic Feedstocks (high in cellulose and hemicellulose):

• Nutshells (e.g., almond, walnut, pistachio)
• Rice hulls

Suitable for biofuels, bioplastics, and various chemical applications.

3. Oil-Rich Feedstocks:

• Spent coffee grounds
• Fruit seeds (e.g., grape seeds/pomace, cherry pits)
•  Soapstocks

These can be used for biodiesel production, lubricants, and cosmetics.

4. Protein-Rich Feedstocks:

• Distillers dried grains with solubles (DDGS)
• Oilseed meals (e.g., soybean meal after oil extraction)
• Insect farming residues

This diverse range of feedstocks opens up many possibilities in the bioeconomy, each with unique challenges and opportunities.

The (Domestic) Scale of the Opportunity

While the economics of next-gen feedstocks can vary widely between regions, potentially making offshore sourcing and production appear cost-effective, North America’s abundant agricultural residues present a compelling case for domestic utilization. In the United States, the numbers are staggering. Based on USDA crop estimates and industry crop residue ratios, in 2023:

• The almond industry produced over 800,000 tons of shells
• Walnut processing left behind approximately 350,000 tons of shells
• Rice production generated about 1.8 million tons of hulls and 8.8 million tons of straw
• Coffee consumers left behind hundreds of thousands of tons of spent coffee grounds
• Sugar beet processing resulted in millions of tons of sugar beet pulp

These quantities of next-gen feedstocks represent an enormous untapped potential for the bioeconomy.

These waste streams are substantial enough to support various bioeconomy sectors locally, offering several advantages:

1. Enhanced supply chain resilience
2. Improved domestic security
3. Reduced economic and environmental costs associated with long-distance transportation

The utilization of both primary and non-primary crop residues as feedstocks is driving innovation across multiple sectors, including biofuels, biochemicals, bioplastics, and advanced materials. This approach aligns with circular economy principles by valorizing what was previously considered waste, providing US farmers with additional revenue streams and reducing the overall environmental footprint of agriculture. As research and technology continue to advance, the range of applications for agricultural residues is expected to expand, further solidifying their role as vital feedstocks for the next generation of bio-based products and processes in the sustainable bioeconomy of the future.

Looking Ahead

In Part 2 of this series, we’ll explore the challenges and opportunities in harnessing these diverse next-gen feedstocks and dive into the systematic approach used to analyze their viability. We’ll see how the compositional requirements of different applications drive feedstock selection and processing strategies. Stay tuned to learn how researchers and industry experts are working to unlock the full potential of these agricultural byproducts in the bioeconomy.

© 2024 | Jennifer Kaplan​​​​​​​​​

This piece also appeared in BiofuelsDigest.