Aims

Natural niches and transmission routes of lactic acid bacteria (LAB) are highly versatile. Proposed routes of transmission to food fermentations are from plant material via insects or vice versa. This study aimed to establish a method for the selective isolation of LAB from insects.

Methods and Results

Varied parameters that influence growth and selectivity are temperature, type of carbohydrate and atmosphere. Additionally, effects of antibiotics to suppress non-LAB species were evaluated.

A model consortium consisting of 12 species representing different lifestyles was inoculated in growth medium to identify conditions for highest diversity and recovery rate. The method was applied to isolate LAB from Drosophila melanogaster, Sitotroga cerealella, Tribolium castaneum and Tenebrio molitor. Isolated species were Leuconostoc mesenteroides, Paucilactobacillus vaccinostercus and Lactiplantibacillus plantarum from D. melanogaster and L. mesenteroides, Pediococcus pentosaceus and Latilactobacillus curvatus from T. molitor. No LAB could be isolated from T. castaneum and S. cerealella. 16S rDNA amplicon sequencing of DNA obtained from insects corroborated part of our results.

Conclusion

A combination of different enrichment conditions ensures a high probability to isolate LAB species from insects and can be helpful above already known non-cultivation methods.

Significance and Impact of the Study

The novel method allows to selectively isolate LAB from insects and the strategy of the method is of interest to study other niches.