New Bioprocessing Method Yields Additional Valuable Byproducts Along with Biofuels

     New research published in the journal Bioresource Technology shows that under the right circumstances valuable byproducts can be extracted and produced alongside biofuels with a new bioprocessing method. The new biorefining method was developed by researchers at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI). They used oilcane, a type of transgenic sugarcane, that accumulates valuable lipids in its vegetative tissues. Specifically, they used oilcane bagasse (OCB), which is the dry pulpy fibrous material that remains after crushing the sugarcane stalks to extract their juice. The vegetative lipids, along with anthocyanins, which are natural colorants, were for recovered during bioprocessing. According to Phys.org:

"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.

The recovery of anthocyanins is significant since it would be cheaper than extracting them from valuable foods which makes them compete with food production, which is currently practiced. Anthocyanins are concentrated in the rinds of the sugarcane. Although they are used as nutrient supplements, their main use is as dyes, or natural colorants, for cosmetics, food, pharmaceuticals, textiles, and more. An alternative is to refine these dyes with industrial solvents which add significant potential health and environmental impacts.

"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."

Producing multiple high-value products from a single feedstock aids efficiency and economics. Oilcane is a highly productive bioenergy crop and refining it to produce multiple products is an opportunity to develop profitable biorefining ventures.

"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 establishing a sustainable circular economy."

     The paper’s abstract is below.

Abstract

“Bioenergy crops have been known for their ability to produce biofuels and bioproducts. In this study, the product portfolio of recently developed transgenic sugarcane (oilcane) bagasse has been redefined for recovering natural pigments (anthocyanins), sugars, and vegetative lipids. The total anthocyanin content in oilcane bagasse has been estimated as 92.9 ± 18.9 µg/g of dried bagasse with cyanidin-3-glucoside (13.5 ± 18.9 µg per g of dried bagasse) as the most prominent anthocyanin present. More than 85 % (w/w) of the total anthocyanins were recovered from oilcane bagasse at a pretreatment temperature of 150 °C for 15 min. These conditions for the hydrothermal pretreatment also led to a 2-fold increase in the glucose yield upon the enzymatic saccharification of the pretreated bagasse. Further, a 1.5-fold enrichment of the vegetative lipids was demonstrated in the pretreated residue. Re-defining green biorefineries with multiple high-value products in a zero-waste approach is the need of the hour for attaining sustainability.”

The 85% recovery rate at 150 deg C and the 1.5-fold enrichment of the vegetative lipids seem to be indications that this process can be economically attractive for oilcane biofuels producers and possibly other biofuels producers in the future.

     The authors call for an integrated biorefinery approach where all of the feedstock is utilized for multiple products. Bioenergy grasses which include sugarcane are often highly productive.

“Genetic modification of sugarcane has been carried out to improve its productivity, accumulate vegetative lipids, and ultimately improve its potential as a bioenergy crop.”

“The current study focuses on redefining the portfolio of products obtained from transgenic oilcane bagasse (OCB). Oilcane is a metabolically engineered sugarcane (Saccharum spp. hybrid) with the ability to accumulate lipids in its vegetative tissues to provide an advanced feedstock for biodiesel production (Parajuli et al., 2020).”

     Some relevant figures and tables from the paper and a relevant excerpt from the paper’s conclusion are given below.

 

 

 

 

“The enhancement in the enzymatic digestibility of the OCB was evident from a 2-fold increase in the glucose yield from pretreated bagasse. The highlighting feature of this chemical-free process is that there is no additional unit operation required for extracting anthocyanins because hydrothermal pretreatment is already an essential component of biomass processing for reducing its recalcitrance. Further, the vegetative lipid concentration increased by 1.5-fold in the pretreated residue. Enzymatic hydrolysis releases a stream rich in sugars which could be fermented to produce biofuels and biobased chemicals. Based upon the high productivity of the bioenergy crops, this re-defined biorefinery approach for complete utilization of OCB creates an opportunity to build a diverse industry to manufacture industrially relevant biobased products.”

 

References:

 

Bioprocessing method yields high-value products alongside biofuels. April Wendling. Phys.org. February 25, 2025. Bioprocessing method yields high-value products alongside biofuels

Redefining the product portfolio of oilcane bagasse biorefinery: Recovering natural colorants, vegetative lipids and sugars. Shivali Banerjee, Galit Beraja, Kristen K. Eilts, and Vijay Singh. Bioresource Technology. Volume 419, March 2025, 132052. Redefining the product portfolio of oilcane bagasse biorefinery: Recovering natural colorants, vegetative lipids and sugars - ScienceDirect