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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Research Project #439523

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

Location: Commodity Utilization Research

2021 Annual Report

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.

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 first annual report for a new project and there are no milestones in FY2021. The new project focuses on issues related to the processing of sugar crops for food use and the use of byproduct streams for food-based products and nonfood biobased fuels, chemicals and products. Progress was made on new project objectives as well as close-out activities for the old project objectives, all of which fall under 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 including hides), 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. While the project has no milestones in FY2021, progress was made by ARS researchers in New Orleans, Louisiana on FY2022 milestones. In support of Objective 2, ARS researchers at New Orleans, Louisiana, collected fresh and legacy clarification mud across Louisiana and Florida sugarcane mills. Florida serves as a model state where this mill mud is successfully recycled back to rebuild fertile “muck” soil. In Louisiana, it is possible that the mill mud could be used to rebuild flood-prone Louisiana soybean field. Although highly dependent on post-treatments and aging, it was found that Louisiana mill muds had promising phosphorus, potassium, stable nitrogen, and premium organic fertilizer values. Greenhouse trials suggested a rapid change in soil biota near roots and in topsoil by mill mud, in time scale of weeks to months. In support of Objective 3, the presence of aconitic acid was determined in sugarcane syrup and molasses from samples collected by ARS researchers in New Orleans, Louisiana from the end of October 2019 to early December 2019 to see if there was a seasonal variability of aconitic acid in the two sugar streams. Analysis of the data by ARS researchers in New Orleans, Louisiana showed that there was no clear trend in the levels of aconitic acid in syrup and molasses across the season. This would suggest that this chemical could be recovered at any time during the season from the sugarcane stream investigated. ARS researchers at New Orleans, Louisiana, shared the results with stakeholders at a workshop in June 2021. Also, in support of this objective, an extensive literature review was performed on aconitic acid and its uses. The review will be published. Also under this objective, an extensive literature review was performed by ARS researchers in New Orleans, Louisiana on acetoin, its uses, and potential for sustainable production. The review will be published. Molecule solubility was studied by ARS researchers in New Orleans, Louisiana with machine learning tools. This knowledge will assist with the research under this objective that involves extraction, and this work may be extended to study other properties. In support of Objective 3, laboratory experiment performed by ARS researchers at New Orleans, Louisiana, showing that acetoin, an important chemical building block for chemical synthesis, can be produced via bacterial fermentation from sugarcane molasses and sugar beet thick juice. The expected amount of acetoin was produced from sugar beet thick juice; however, only 40% of the expected amount was produced from the sugarcane molasses. Further experimentation is needed to investigate the reason for the results. The research also showed that the conditions of the cost of the process could be reduced by eliminating (or reducing) some complex nitrogen sources. Also related to Objective 3, progress was made on research under agreement number 66450 with Cotton Incorporated, where ARS researchers at New Orleans, Louisiana, investigated the need for contaminant removal from sugar solutions obtained from solubilized discarded textiles, in order to ferment the sugar solutions to biochemicals. Two types of fermentation experiments were conducted: The first looked at a fermentation where sugars are converted to butanol in the absence of air. Here activated carbon added to the fermentation removed inhibitors and allowed more butanol to be produced. The second fermentation experiments looked at fermentation where sugars are converted to acetoin in the presence of air. Here, activated carbon was not needed to produce the expected levels of acetoin. The results were shared with Cotton Incorporated in quarterly reports.

1. Robust assays to classify organic fertilizers. An ARS scientist in New Orleans, Louisiana, and collaborators developed a method to categorize soil amendments genetically (e.g., drought tolerant microbial community) and chemically (e.g., sensitivity to sunlight exposure). This method offers producers a tool to predict efficacy of soil conditioners. Historical burning of sugarcane fields in Louisiana has removed beneficial microbiota and made soils sandy. An economical way to replenish eroded soil and foster climate resilience is to apply sugarcane mill mud, a leftover activated sludge from raw sugar production. New assays predict which chemical properties govern microbial communities making up the mill mud organic fertilizer. Developed assays serve as a decision maker for producers to select suitable fertilizer from different source material, aging process, and location.

2. Identifying sugarcane by-product characteristics and processing conditions that generate high value products. ARS researchers in New Orleans, Louisiana, believe approximately 1 million tons of surplus sugarcane bagasse goes unused. Additionally, sugarcane harvesting can generate up to 2 million tons of field residue. Currently, bagasse piles cost mills several million dollars annually, to manage and maintain. ARS researchers in New Orleans, Louisiana, identified ways to convert these unused biomass materials into value-added products, such as high-density low ash fuel pellets, low density adsorption pellets and biochar for soil amendment. Together with industrial partners, key processing parameters are being identified for optimization, understanding that these products need to be competitive with current commercially available materials. Ultimately, additional revenue for the mills is expected along with addressing a waste problem.

Review Publications
Klasson, K.T., Boone, S.A. 2021. Bioethanol fermentation of clarified sweet sorghum (Sorghum bicolor (L.) Moench) syrups sealed and stored under vegetable oil. Industrial Crops and Products. 163.
Eggleston, G., Boue, S., Bett Garber, K., Verret, C., Triplett, A., Bechtel, P. 2020. Phenolic contents, antioxidant potential and associated colour in sweet sorghum syrups compared to other commercial syrup sweeteners. Journal of the Science of Food and Agriculture.
Lima, I.M., Clayton, C., Tir, A., Wierdak, A., Parker, C., Sarir, E., Eggleston, G. 2021. Design and operation of a scaled-up pilot plant for the removal of sugar beet extract colorants using powdered activated carbons. Sugar Tech. 23(1):167-177.
Uchimiya, M. 2020. Proton-coupled electron transfers of defense phytochemicals in sorghum (Sorghum bicolor (L.) Moench). Journal of Agricultural and Food Chemistry. 68(46):12978-12983.