Description of Paralactobacillus selangorensis gen. nov., sp. nov., a new lactic acid bacterium isolated from chili bo, a Malaysian food ingredient

Researchers isolated and characterized a novel lactic acid bacterium from chili bo, a traditional Malaysian food ingredient. The organism was identified as a new genus and species, Paralactobacillus selangorensis, based on comprehensive molecular and phenotypic analysis. Five representative strains were examined for their biochemical and physiological properties, DNA composition, and genetic relatedness. The bacterium is rod-shaped, gram-positive, and obligatory homofermentative, producing both D- and L-lactic acid from glucose in a ratio of approximately 1.6-2:1. The DNA G+C content is 46 mol%, and phylogenetic analysis of 16S rRNA sequences showed that P. selangorensis is distantly related to the Lactobacillus casei–Pediococcus group. While phenotypic differentiation from related homofermentative Lactobacillus species requires multiple tests, the genetic evidence clearly supports designation as an independent genus within lactic acid bacteria. The type strain LMG 17710T and related strains displayed consistent phenotypic characteristics distinguishing them from other LAB genera, particularly regarding their inability to produce gas from glucose and their specific carbohydrate utilization patterns.

Key findings

• Paralactobacillus selangorensis is a new genus and species of obligatory homofermentative lactic acid bacterium isolated from Malaysian chili bo, designated with type strain LMG 17710T
• The organism has a DNA G+C content of 46 mol% and produces both D- and L-lactic acid in a 1.6-2:1 ratio with minimal acetic acid and ethanol
• 16S rRNA sequence analysis demonstrates P. selangorensis is distantly related to the Lactobacillus casei–Pediococcus group with only 90.1-91.7% sequence similarity
• The new genus can be differentiated from other homofermentative Lactobacillus species through a combination of phenotypic characteristics including inability to produce gas from glucose and specific carbohydrate utilization patterns
• DNA-DNA hybridization studies and fatty acid composition analysis confirm the five characterized strains represent a single, homogeneous genomic species