Steam explosion and fermentation of sugar beets from Southern Florida and the Midwestern United States

Authors: Dorado, Christina; Cameron, Randall - Randy; COOPER, KEVIN - Indian River State College

Submitted to: Biocatalysis and Agricultural Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2017
Publication Date: 6/1/2017
Citation: Dorado, C., Cameron, R.G., Cooper, K. 2017. Steam explosion and fermentation of sugar beets from Southern Florida and the Midwestern United States. Biocatalysis and Agricultural Biotechnology. 11:26-33.. https://doi.org/10.1016/j.bcab.2017.05.007.
DOI: https://doi.org/10.1016/j.bcab.2017.05.007

Interpretive Summary: Florida is the largest sugarcane producing region in the United States. Another major sugar crop grown in the U.S. is the sugar beet. While sugar beet production is concentrated mostly in the Midwest United States for the production of table sugar there has been an increase in interest for cultivation in other areas of the U.S. for use as animal feed, fuel ethanol production and as a soil nutrient accumulation crop to prevent runoff into waterways. The latter being particularly applicable to southern Florida where sugar beets could be used to combat the algae blooms that plague the Florida Treasure Coast during the hot summer months and are suspected to be partly caused by run off from agricultural land. Another possible use for sugar beets in Florida could be as cattle feed. Florida registered a total of 1.69 million cattle and calves for 2016 with $410 million spent on animal feed in Florida in 2015. Sugar beets are also being considered as a possible feedstock for fuel ethanol production considering that, in 2013, Florida consumed 18.9 million barrels of fuel ethanol and produced none. With an already established infrastructure for sugar cane milling and ethanol production from agricultural crops and residues pursuing sugar beets as an energy crop could be economically favorable. Another potential value added product from sugar beets is pectin. The unique structure and properties of sugar beet pectin can be exploited for use in pharmaceuticals, nutraceuticals, cosmetics and functional foods making it a desirable value added product from sugar beets. In this work we present data from the steam treatment and fermentation of sugar beets. Pilot scale fermentations of the steam exploded sugar beet gave 6.7-9.7 percent ethanol by volume and total pectic hydrocolloid sugars and total compositional sugars were similar for steam exploded sugar beets from the Midwestern United States and southern Florida. Liming and pressing of sugar beets produced a sugar rich liquid and solid.

Technical Abstract: Sugar beets have recently gained interest for cultivation in southern Florida for their economic potential as cattle feed, a feedstock for ethanol production and their use to improve the quality of water via soil nutrient accumulation. Sugar beets grown in southern Florida, Minnesota and Nebraska were subjected to steam explosion. Analysis of soluble and insoluble sugars as well as pectin from raw and steam exploded sugar beet were completed. Fermentations of raw and steam exploded sugar beets, with and without enzymes, were conducted. There was no significant difference for ethanol production in the fermentation of steam exploded sugar beets with and without enzymes indicating that addition of enzymes are not necessary for fermentation. Pilot scale fermentations of the steam exploded sugar beet gave 6.7-9.7 percent ethanol by volume. Raw, milled sugar beet were limed and pressed. The press cake and press liquor were analyzed for dry weight and sugar content.