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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #421557
Research Project: Improved Conversion of Sugar Crops into Food, Biofuels, Biochemicals, and Bioproducts

Location: Commodity Utilization Research

Title: Microbial control from concurrent application of enzymes and antimicrobial agents on sugarcane processing bacteria and exopolysaccharides

Author
item Terrell, Evan
item Bruni, Gillian
item Lima, Isabel

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 8/22/2025
Publication Date: 8/24/2025
Citation: Terrell, E.C., Bruni, G.O., Lima, I.M. 2025. Microbial control from concurrent application of enzymes and antimicrobial agents on sugarcane processing bacteria and exopolysaccharides.Proceedings of the International Society of Sugar Cane Technologists, 32. pg 1350-1355.

Interpretive Summary:

Technical Abstract: A persistent issue faced during raw sugar manufacturing is the presence of contaminant bacteria (e.g., Leuconostoc sp.) and their associated exopolysaccharides (EPS; e.g., dextrans and fructans). These microorganisms consume sucrose directly, decreasing product revenue, while also generating EPS that elevate viscosities and introduce operational challenges and associated costs. In this study, bacterial isolates from sugar crop processing facilities were collected and grown on high-sucrose liquid media in the presence of an oxidizing antimicrobial agent, a dextranase enzyme, and both treatments concurrently. We hypothesize that the presence of EPS confers some additional resistance to bacteria (particularly in biofilms), making them less susceptible to microbial control measures. Following growth experiments, bacterial growth and EPS production was quantified using optical density (OD) and culture viscosity measurements. Results show that untreated controls of bacterial cultures had very high culture viscosity and OD, with treatment bacterial cultures being significantly lower. Application of dextranase as a treatment alone resulted in somewhat elevated OD and viscosity values for resulting culture solutions. The antimicrobial treatment was more effective at inhibiting microbial growth; however, the lowest OD and viscosities resulted from the concurrent application of both enzyme and biocide together. These results provide some evidence to support the hypothesis that EPS mitigation strategies may introduce improved microbial control when antimicrobial agents are applied. Through the application of enzymatic treatments, like dextranase(s), bacteria present during sugarcane processing will have less opportunity to form EPS and biofilms. As a result, this could potentially predispose dextran-forming bacteria to control measures, like the application of antimicrobial agents. Importantly, the application of EPS-mitigating enzymatic treatments with “biocide” treatments could confer synergistic benefits for microbial control, beyond those realized through applications of these treatments individually. Overall, this strategy can improve operational efficiencies by decreasing required volumes/costs for processing aids and increasing raw sugar production.