| Abstrakt: |
During microbial deterioration of sugarcane, a variety of extracellular polysaccharides (EPS, e.g., dextran, fructans) and other impurities (e.g., organic acids, sugar alcohols, alcohols) are produced. The microbial-derived EPS dextran (a polymer of glucose) has generally been considered the main problem in sugarcane processing, with its main production source being attributed to the bacterium Leuconostoc mesenteroides. Technical problems associated with the presence of dextran at the sugar factory can affect every step of sugar processing resulting in high viscosities, reduced efficiencies, elongation of sugar crystals, and the loss of sucrose to molasses. In recent years, fructans (a polymer of fructose) concentrations have been increasingly reported in both cane juice and molasses at Louisiana sugar factories. With the limited information that exists on the microbial origin of fructans at the sugar factories and its possible impact on Louisiana sugarcane processing, this research study aimed at identifying the microbial populations present in high numbers in the crusher juice or first extraction juice, and determining the effect of processing conditions on their ability to produce EPS. Our findings indicate that Lactobacillus, Lactococcus, Leuconostoc, Pantoea, Pseudomonas, and Saccharomyces were the microbial genera present in high cell numbers and that all isolates were capable of producing dextran and/or fructans. Leuconostoc had the most diverse number of species. A single isolate of L. suionicum A14 was identified and produced only fructans from sucrose. This is the first study to report on a fructan-only producing Leuconostoc isolate from sugarcane. EPS production was affected by temperature, sucrose concentrations, and medium pH. [ABSTRACT FROM AUTHOR] |
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