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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #412998
Research Project: Improved Conversion of Sugar Crops into Food, Biofuels, Biochemicals, and Bioproducts

Location: Commodity Utilization Research

Title: Molecular cloning of bacterial exopolysaccharide forming enzymes in sugarcane processing and biological and agricultural applications

Author
item Fein, Jack
item Qi, Yunci
item Bruni, Gillian
item Terrell, Evan

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/13/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In the post-harvest processing of sugarcane to raw sugar, microbial activity results in the loss of sucrose and the production of contaminant exopolysaccharides (EPS). The most studied producers of EPS in the context of raw sugar production are Leuconostoc spp., which produce a dextran EPS constructed of repeating glucose units, using dextransucrase enzymes. Analogous levansucrase enzymes are also present many microorganisms, which produce levan fructan EPS during sugar crop processing. Levan producing bacteria include Gluconobacter, Bacillus, and Pseudomonas, among other microbes. These EPS introduce engineering challenges for processing facilities, particularly related to viscosity, crystallization, and the presence of biofilms. Leuconostoc lactis strain LASM16 was previously isolated from a raw sugar factory in Louisiana and characterized as a dextran-producing strain and its genome was sequenced. To further study the dextran produced by this strain, the DNA sequence coding for a dextransucrase enzyme (dsrLASM16) was inserted into the pET21a expression vector. This plasmid was then transformed into E. coli strain BL21 (DE3) for protein production, from which the resulting dextransucrase enzyme was purified by Nickel affinity chromatography. Additional isolations of other dextransucrases and levansucrases is ongoing. Isolations of these enzymes forms the basis for further investigations for biological and agricultural engineering, as it relates to sugar crop processing. Future work will explore cell free synthesis of dextran and levan EPS, and rigorous characterization of the resulting EPS. Inhibition studies for dextran- and levansucrases enzymes are also planned. These results will also be used to inform microbial control and EPS mitigation strategies for agricultural industry stakeholders.