Bioprocessing method yields high-value products alongside biofuels

Researchers at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) have developed a sustainable process that has redefined and expanded oilcane’s product portfolio, adding value to this feedstock.

In a traditional biorefinery, sugarcane is used as a feedstock to produce bioethanol fuel. Sugarcane stalks are crushed to extract their juice, and that juice goes on to be processed into fuel. Meanwhile, the dry fibrous material that remains after crushing, called bagasse, is burned.

In their new study, published in Bioresource Technology, CABBI researchers developed a biorefinery process that recovers the high-value products present in oilcane bagasse, meaning that multiple product streams can be generated from this single feedstock. This work could assist in providing a sustainable source of energy to meet societal needs, while also generating additional streams of revenue in the form of co-products.

The researchers used oilcane, a type of transgenic sugarcane, that accumulates valuable lipids in its vegetative tissues. They targeted these vegetative lipids, along with anthocyanins, which are natural colorants, for recovery during bioprocessing.

“We first analyzed the composition of the oilcane, selected the most valuable products, and then developed a sustainable process that could give us enhanced recovery of the selected high-value products along with the production of biofuels,” said Shivali Banerjee, first author on the study and Postdoctoral Research Associate in the Department of Agricultural and Biological Engineering at University of Illinois at Urbana-Champaign.

Anthocyanins are pigments that are responsible for a variety of colors in fruits, vegetables, grains, and flowers. They are widely used as natural colorants in cosmetics, food, pharmaceuticals, and textiles, and are a safer alternative to synthetic dyes.

However, the cost of producing and recovering these natural pigments is typically higher than that of synthetic pigments. This is because many anthocyanin-rich sources such as berries and red cabbages already have existing markets in the food sector. By recovering anthocyanins from oilcane bagasse instead, these pigments can be produced at a lower cost and avoid conflict with the production of food.

“It’s a win-win situation,” said Banerjee. “In addition to natural colorants, we can also recover vegetative lipids and sugars for biofuel production, all from just one feedstock.”

CABBI’s overall bioenergy mission is to develop efficient ways to grow bioenergy crops, transform biomass into valuable chemicals, and market the resulting biofuels and other bioproducts. From an economic perspective, it is important that biofuels are produced at a low cost. Recovering high-value co-products from a feedstock during biofuel production can make the process of biofuel production more cost-effective.

“Maximizing the conversion of all biomass components is critical to developing a profitable bio-refinery,” said Vijay Singh, team lead on the study, CABBI’s Deputy Director for Science & Technology, Distinguished and Founder Professor of Agricultural and Biological Engineering (ABE), and Executive Director of the Integrated Bioprocessing Research Laboratory (IBRL) at Illinois.

Based upon the high productivity of these bioenergy crops, this redefined biorefinery approach for complete utilization of bagasse creates an opportunity to build a diverse industry to manufacture industrially relevant bio-based products.

“Similar efforts could be made for other CABBI feedstocks as well,” Banerjee said. “Redefining a biorefinery to produce a diverse portfolio of bio-based products in a zero-waste approach is the need of the hour. This would assist in overcoming the barriers to establish a sustainable circular economy.”

Other co-authors on this paper include Kristen Eilts, Lab Research Specialist in the Department of Agricultural and Biological Engineering at Illinois; and Galit Beraja, a 2023 participant in CABBI’s Research Internship in Sustainable BioEnergy (RISE) program at Illinois.

During CABBI’s RISE program, Beraja was trained to run experiments on green extraction strategies for recovering natural colorants from bioenergy crops. She estimated the total anthocyanin concentration in oilcane bagasse and assisted in optimizing the process conditions for recovering this natural pigment along with the recovery of vegetative lipids.

“My experience as a CABBI intern is one I will forever be grateful for,” said Beraja. “I was able to learn about multiple steps involved in the research process, sharpen my lab skills, further define my career path and interests, and gain so much knowledge from my amazing mentor, Shivali.”

Throughout her time in the RISE program, Beraja contributed to this research through composition analysis, pigment extraction, and vegetative lipid recovery. She also honed her skills in science communication through her work on the manuscript and presenting experimental data. This is just one example of how the RISE program builds a talent pipeline for the broader bioenergy research community.

— News release by CABBI Communications Specialist April Wendling