Abstract
High levels of gums such as dextran, produced by Leuconostoc and Lactobacillus spp., have a severe impact on factory throughput and sugar quality. This study aimed to determine the phylogenetic relationships between gum‐producing Leuconostoc and Lactobacillus bacteria which were isolated from various locations in a sugarcane processing factory at times when low‐ and high‐dextran raw sugar, respectively, were produced. Phylogenetic analysis of 16S rRNA gene sequences grouped 81 isolates with the type strains of Leuconostoc mesenteroides (subspp. mesenteroides, dextranicum, and cremoris), Leuconostoc pseudomesenteroides, Leuconostoc lactis, and Leuconostoc citreum, respectively. Forty‐three isolates clustered with the type strain of Lactobacillus fermentum. The phylogenetic relatedness of the isolates was determined by sequencing and analysis of the housekeeping genes rpoA and dnaA for Leuconostoc spp. and the pheS and tuf genes for the Lactobacillus spp. The rpoA gene proved discriminatory for the phylogenetic resolution of all of the isolated Leuconostoc spp. and the dnaA housekeeping gene was shown to be effective for isolates clustering with the type strains of Leuc. mesenteroides and Leuc. citreum. None of the loci examined permitted differentiation at the subspecies level of Leuc. mesenteroides. Single‐locus analysis, as well as the concatenation of the pheS and tuf housekeeping gene sequences, yielded identical phylogenies for the Lactobacillus isolates corresponding to L. fermentum.
Highlights
Problems encountered with microbial degradation of harvested sugarcane, followed by further spoilage during processing, leads to a poor-quality sugar and severe economic losses
This study aimed to determine the phylogenetic relationships between the isolated Leuconostoc and Lactobacillus bacteria based on the phylogenetic relatedness of selected housekeeping gene sequences
This study showed that the number of lactobacilli at the various locations at both sampling times was similar and all species were found to be related to L. fermentum
Summary
Problems encountered with microbial degradation of harvested sugarcane, followed by further spoilage during processing, leads to a poor-quality sugar and severe economic losses. Microbial exopolysaccharides such as dextran are referred to as “gums.” Spoilage bacteria in sugarcane processing have historically been identified by phenotypic methods, which failed to accurately differentiate between the genera Leuconostoc and Lactobacillus and between species within the genus Leuconostoc (Maniatis, Fritsch, &Sambrook, 1982). The last attempt at the profiling of spoilage bacteria in a sugarcane processing factory was more than 30 years ago. In that study, Lillehoj, Clarke, and Tsang (1984) identified Leuconostoc mesenteroides as the dominant species in factory processing streams. Previous attempts by sugar technologists to identify spoilage bacteria in sugarcane processing factories have all been hampered by the lack of available identification methods of high discriminatory power
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
