Research Project: Improved Conversion of Sugar Crops into Food, Biofuels, Biochemicals, and Bioproducts

Location: Commodity Utilization Research

2025 Annual Report

Objectives
Objective 1 Quantify the impact of new sugar processing aids (chemical oxidizers) in combination with existing ones (e.g., enzymes) on raw cane sugar manufacturing. The research in Objective 1 will address the following sub-objectives: 1.A Evaluation of oxidizing agents and amylase enzyme for the degradation of soluble and insoluble starch in sugarcane juice. 1.B Evaluation of oxidizing agents and dextranase enzyme to control microbial growth and dextran levels in sugarcane juice. 1.C Evaluation of oxidizing agents to reduce sessile microbial growth and film formation on equipment. Objective 2 Develop sustainable, commercially viable, biobased products from sugar cane and sugar beets byproducts (e.g., sugarcane bagasse, sugar beet pulp, clarifier mud/cake). The research in Objective 2 will address the following sub-objectives: 2.A Development of commercially sustainable biobased products from processing byproducts to improve soil health, reduce waste disposal costs for the U.S. sugar manufacturers, and address the food-water-energy nexus. 2.B Development of commercially sustainable biobased products from processing byproducts (bagasse and beet pulp) for high end horticulture products and soil health applications. 2.C Production of biobased polymers from sugarcane molasses, bagasse, and clarifier mud/cake. Objective 3 Enable commercially viable, renewable, biofuels and chemicals from sugar cane and sugar beet processing byproducts (e.g., molasses, clarifier mud/cake). The research in Objective 3 will address the following sub-objectives: 3.A Production of solvents and jet fuel pre-cursors from sugarcane molasses and clarifier mud/cake. 3.B Production of acetoin and 2,3-butanediol from molasses and sugar beet extract. 3.C Recovery of aconitic acid from sugarcane molasses and testing its potential for nematode bioactivity.

Approach
Modern sugar production for human consumption, and as a starting point for fermentations, has existed for centuries. While the sugar manufacturing technology is well known, there is a need by the sugar industry to improve processing and develop new coproducts to increase the profitability for farmers and processors. This can be accomplished by * reducing chemicals used to control starch and dextran in raw sugar manufacturing, * improving the quality of the raw sugar to minimize refining costs, * reducing sugar losses by microbial action by improving sanitation, and * more effectively utilizing the byproducts to make coproducts. Therefore, to address these goals our research will focus on * identify impact and optimize the use of processing aids to improve the sugar quality while reducing the cost, * develop biobased products from sugar manufacturing byproducts, and * develop renewable biofuels and biochemicals from sugar manufacturing byproducts. The byproducts targeted to produce the bioproducts and biochemicals are * bagasse, clarifier mud/cake, and molasses from sugarcane processing, and * pulp, and beet extract from sugarbeet processing. In any research effort, it is important that performance metrics are established. Thus, each sub-objective has its own performance metrics. In all cases, an economic analysis will be performed to determine cost of implementation. In addition, the impact of byproduct use or process changes will be evaluated in collaboration with local (or impacted) industry using a limited life cycle assessment around the system altered. The outcome of this research will result in the following anticipated products: * a lower cost, cleaner process, and improved raw sugar from sugarcane factories, * advanced fertilizers and high-end soil amendments, * composite polymers, and * biochemicals for solvents and fuels, as precursors to other chemicals, and for pest control.

Progress Report
This is the final report for project 6054-41000-114-000-D, Improved Conversion of Sugar Crops into Food, Biofuels, Biochemicals, and Bioproducts, which was replaced by new project 6054-30600-003-000-D, Sugar Crop Processing Improvement and Sustainable Co-product Development, in May 2025. The project focused on solving problems related to the processing of sugar crops for food use and developing value-added byproduct streams for food- and nonfood-based products. Progress was made on all objectives, significantly contributing to goals of National Program 306, Component 1 – Foods, Problem Statement 1A: Define, Measure, and Preserve/Enhance/Reduce Factors that Impact Quality and Marketability; Component 2 – Nonfood (fibers), Problem Statement 2B: Enable technologies to produce new and expand marketable nonfood, nonfuel biobased products derived from agricultural feedstocks; and Component 3 – Biorefining, Problem Statement 3A: Viable Technologies for Producing Advanced Biofuels (including Biodiesel), or other Marketable Biobased Products. In support of Objective 1, ARS researchers in New Orleans, Louisiana identified 1,000 microbial isolates-and studied 58 of the bacteria- obtained from samples collected at 18 sugar beet factories across North America located in North Dakota, Montana, Minnesota, Idaho, Michigan, California, and Alberta (Canada). Bacteria consume sugar as they grow, which reduces the yield of sucrose (and profits) in sugar factories. The scientists studied several industrial chemicals called “biocides” to determine the minimum levels required to stop microbial growth and halt sucrose losses. The scientists also used factory data to calculate the “breakeven” prices of these industrial biocides to indicate if it would be profitable to apply a particular biocide at a recommended dose. Elevated temperature was also found to be effective against several factory bacteria, and the results were summarized in a manuscript submitted for publication. Also in support of Objective 1, the scientists collected daily factory-scale manufacturing data from sugar mills in Louisiana. Starch and dextran are polysaccharides that occur naturally during sugar crop processing but interfere with raw sugar production. Using the sugar mill data, machine learning analyses were conducted to quantify the impact of starch and dextran on raw sugar production. This work will be shared with stakeholders and scientists at an international sugarcane conference. The results support sugar mills in making economically viable decisions about engineering, operations, and processing aid (enzymes and other chemicals) application for the control of issues caused by starch and dextran. In support of Objective 1, ARS researchers successfully grew biofilms from nine sugar beet factory bacterial samples. A biofilm is a highly structured community of bacteria and other microbes that attach to each other and to surfaces and are typically covered and protected by a layer of proteins, polysaccharides and other polymers. Biofilm formation on sugar processing factory surfaces reduces sugar yield and profitability. Overall bacterial growth, and ability to produce biofilms differed between the bacterial types, underscoring the importance of testing multiple isolates from both sugar crop juice and biofilm factory samples. Additionally, genes that produce biofilm-forming enzymes were identified in the DNA sequences of candidate bacterial strains. Closer study of these genes will help to predict propensity of different strains to form biofilms. Additional work was conducted in collaboration with University of Georgia, under agreement 6054-41000-114-008S to elucidate the size and structure of the polysaccharides, contributing to better understanding of the operational challenges caused by bacterial growth on factory surfaces. This work is being documented in multiple manuscripts under review or in preparation for publication. A challenge addressed in Objective 2 is the development of processes that will add value to sugar processing by-products. Different by-product treatments, including thermal, electrochemical, photochemical, and enzymatic, were developed. Thermal treatment pasteurized the by-products to limit their microbial content and composition. Electrochemical conversion at different applied voltages was used to alter the chemical structures of the by-products. Microbial conversion led to the formation of light absorbing chemicals called chromophores, which are prone to oxidation by light. Photochemical conversion of thermally treated sugarcane mill mud will produce carbon sources to feed beneficial soil microbes in potting mixes. These different conversion methods represent tunable ‘tools’ that help stakeholders convert low-value starting materials into products that more closely match target specifications for value-added end-products such as fertilizers. Agreement 58-6054-3-015 with the American Sugarcane League also supported research on Objective 2. Computer models were developed to predict the levels of important chemicals in sugarcane by monitoring crop canopy using unmanned aerial drones. The chemicals in question act as anti-freeze agents that promote stable overwintering in Louisiana, the northernmost sugarcane growing region in the world. Development of forecasting technology by remote sensing offers a non-destructive precision breeding tool for the sugar industry, especially during times of labor shortages. Developing cold-tolerant sugarcane varieties is one of the top industry priorities. In support of Objective 2, the ARS scientists acquired by-product samples from Louisiana sugar mills and manufactured biochars, a plant-based carbon-rich material generated by high temperatures in the absence of air. Biochars are used to supplement soils to promote better crop yields and in many other applications. After detailed analysis, the final biochar properties were correlated to the composition and characteristics of the by-product feedstocks used to generate them. These biochars will be used in greenhouse studies and as adsorbents for removal of impurities (such as color compounds) from sugar refinery processing streams to evaluate their potential for improving profits for sugar producers. Also in support of Objective 2, under agreement 58-6054-4-0043 with the University of Georgia, biochar batches were produced at different temperatures using either fresh or aged bagasse (the plant material remaining after sugarcane is pressed to remove its juice) feedstocks collected from a Louisiana sugar mill. These biochars were fully characterized and will be tested as a value-added peat moss replacement in greenhouse potting experiments. In additional support of Objective 2, the scientists evaluated the potential of using sucrose, molasses and raw sugar to produce polyurethane plastics. The compounds produced were tough, insoluble, non-moldable plastics. Additional chemical polymers were added to improve the solubility and formability of the composites. Sugarcane bagasse (10–50% by weight) was also added as a composite filler. The new mixtures created with bagasse filler and chemical co-polymers were successfully incorporated into the plastic composites. However, drying and compression molding of the composites produced brittle specimens that were not satisfactory for mechanical testing. Also in support of Objective 3, ARS researchers developed a process to separate and extract a chemical called acetoin from microbial fermentation broth, in which sugar production by-products (such as molasses or sugar beet extract) were used as the carbon source for microbial growth. Acetoin is a natural organic compound used as a flavor additive in the food industry. The researchers found that acetoin could be efficiently extracted from fermentation broths, with large-scale recovery reaching up to 95%. This extracted acetoin could then be catalytically converted to 2,3-butanediol, a versatile compound with a range of applications including foods, flavors, and fragrances, or as a feedstock for biofuels or bioplastics. However, due to lower-than-expected yields of acetoin from fermentation experiments, any production should likely be targeted to lower volume, higher value products like food, flavor, and fragrance applications. These results open new avenues of research for the production of value-added compounds from by-products of the sugar industry. In further support of Objective 3, the researchers developed a separate process to extract aconitic acid from sweet sorghum syrup and sugarcane molasses and identified several value-added industrial and biological functions for aconitic acid. For instance, aconitic acid is useful for green chemistry applications as a plasticizer, cross-linker, and in formulation of multi-functional polymers that are safer for the consumer. Biological applications were also identified including antifungal defense in plants and crop protection as an antifeedant that would broadly benefit consumers and farmers. Numerous value-added applications were published in a first-of-its-kind review article. In summary, the work done during the full course of this project significantly advanced the understanding of microorganisms that cause sugar losses, the associated downstream operational problems, and the costs related to their management. The project also developed several value-added applications for sugar crop processing by-products that will help to create new on-the-farm field applications and improve revenue streams for U.S. agricultural producers. This work supported efforts by sugar crop farms and factories to increase productivity and profitability and strengthen national agricultural security through identification of new potential growth markets for the sugar industry.

Accomplishments
1. Optimal doses of biocides increase sugar yields in factories.. Sugar beet and sugarcane are rich sources of sugar that can be rapidly degraded by microbes after harvest, during transport or storage, and during the sugar extraction process. Microbial growth results in significant sucrose losses and downstream operational challenges, causing multiple negative economic impacts to factories and the industry as a whole. To minimize microbial growth during sugar extraction, ARS scientists in New Orleans, Louisiana, in partnership with several sugar processing factories, determined the optimal dosing concentrations for usage of antimicrobial compounds called “biocides”. The results demonstrated that some biocides could reduce microbial growth by 98 percent when used at the recommended concentration. These findings highlight the value and importance of including antimicrobial “biocides” in the sugar extraction process and enable development of improved practices that increase sugar yields and economic benefits for U.S. farmers and producers.

2. Simple measurements identify the suitability of agricultural by-products for use as fertilizers.. Domestic development of soil amending fertilizers from crop residues and other wastes can increase value and profitability for agricultural producers. One challenge with utilizing agricultural materials like compost, harvesting or processing by-products, or naturally aged plant biomass as soil amendments is determining how and when these materials will be suitable for specific land applications. To address this issue, ARS researchers in New Orleans, Louisiana, in collaboration with scientists from Cornell University, identified key biological parameters that can be used to describe a wide variety of potential soil amendments. This research showed that regardless of original source or processing conditions, any compost material that is suitably mature enough for land application will conform to specific, easy-to-measure values. This is important because it facilitates the development of universal tests that can be used for the assessment of any potential soil amendment derived from biomass. These universal tests will simplify and accelerate the adoption of agricultural by-products and other wastes as soil amending fertilizers.

3. Modeling the economic impact of starch and dextran supports operational efficiency for sugarcane and sugar beet factories.. The extraction of sucrose from sugarcane or sugar beet crops is complicated by the presence of other plant and bacterial-derived contaminants, such as starch and dextran. These polysaccharides can cause operational challenges, hindering the ability of sugar mills to produce crystallized raw sugar. ARS researchers in New Orleans, Louisiana used manufacturing data shared by the sugar industry as the basis for machine learning studies to quantify the economic impact of starch and dextran on sugar production. By understanding the costs associated with starch and dextran impact, sugarcane and sugar beet processors can make more informed engineering decisions to help minimize the presence of these contaminants and increase overall profitability.

4. Development of a working biofilm growth system to increase operational efficiency in sugar factories. Formation of biofilms on sugar factory equipment is a serious operational problem that often requires expensive temporary factory closures for extensive cleaning. A better understanding of which bacteria typically form biofilms, and the mechanisms by which this occurs, is central to mitigating this problem and developing targeted solutions. ARS researchers in New Orleans, Louisiana were able to grow and study the formation of biofilms by nine Leuconostoc bacterial isolates by slowly dripping bacterial liquid over solid surfaces in a laboratory setting. This process models what occurs naturally in sugar factories. Bacterial strains were evaluated for differences in colony forming potential and biofilm biomass. This experimental biofilm model will enable future studies to test antimicrobial and processing aid agents to improve sugar recovery and mitigate biofilm effects in factories, thereby increasing overall profitability

5. Applying sugarcane bagasse biochar to corn and cotton fields increases crop productivity.. Biochar is a valuable high carbon-content product that can be made from sugarcane bagasse, a low-value by-product of raw sugar manufacturing. Biochar has a wide variety of potential applications, including utilization in fields to improve crop productivity. ARS researchers in New Orleans, Louisiana, showed that after the third year of successive biochar applications, cotton fields had up to 22% increase in fiber yield and up to 13% increase in seed yield. For corn, yield increased 16% when compared to untreated crops. These studies demonstrate that successive biochar applications can increase crop yields and benefit crop producers. This also illustrates a potential value-added pathway for consumption of sugarcane bagasse or sugar beet pulp, returning more profit to sugarcane and sugar beet farmers.

Review Publications
Uchimiya, M., Borja Reis, A.F.D., Lago, B.C., Taylor, K., Höner Zu Bentrup, K., Ellis, D., Kimbeng, C. 2024. Freeze response indicators in sugarcane (Saccharum spp. hybrids). Micron. 188: Article 109726. https://doi.org/10.1016/j.micron.2024.103726.
Uchimiya, M., DeRito, C.M., Sevigny, J.L., Hay, A.G. 2024. Meta-analysis of ecological and phylogenetic biomass maturity metrics. Waste Management. 190(15): 548-556. https://doi.org/10.1016/j.wasman.2024.10.023.
Bruni, G.O., Terrell, E.C., Klasson, K.T., Qi, Y. 2025. Control of industrially relevant microbial isolates by antimicrobial agents: Implications for sugar factories. Journal of Industrial Microbiology and Biotechnology. 52. Article kuaf001. https://doi.org/10.1093/jimb/kuaf001.
Aita, G., Bhatnagar, D., Bruni, G.O., Deliberto, M., Eggleston, G., Finger, A., Gravois, K., Judice, W., Klasson, K.T., Lima, I.M., Purswell, J.L., Souliman, M., Terrell, E.C., Tubaña, B., Waguespack, H., Wang, J., White Jr, P.M. 2024. Creating a bio-product based circular economy from Louisiana sugarcane by-products. American Society of Sugar Cane Technologists. https://doi.org/10.1002/ael2.20140.
Pinnamaneni, S.R., Lima, I.M., Boone, S.A., Anapalli, S.S., Reddy, K.N. 2023. Effect of sugarcane biochar on rainfed cotton (Gossypium hirsutum L.) growth, lint yield and quality in the humid Mississippi Delta. Nature Scientific Reports. https://doi.org/10.1038/s41598-023-37820-8.
Pinnamaneni, S., Anapalli, S.S., Lima, I.M., Boone, S.A., Beacorn, J.A., Bellaloui, N., Reddy, K.N. 2023. Effects of pelleted sugarcane biochar applications on growth, yield and economics of rainfed corn (Zea mays L.) in the Mississippi Delta. Industrial Crops and Products. Industrial Crops & Products 204 (2023) 117318. https://doi.org/10.1016/j.indcrop.2023.117318.
Pignatello, J.J., Uchimiya, M., Abiven, S. 2024. Aging of biochar in soils and its implications. In: Lehmann, J., Joseph, S., editors. Biochar for Environmental Management. 3rd edition. London: Routledge. p. 249-276. https://doi.org/10.4324/9781003297673-10.
Uchimiya, M. 2024. Big data-driven water research towards metaverse. Water Science and Engineering Journal. 17(2):101-107. https://doi.org/10.1016/j.wse.2024.02.001.