Characterization of bacteria from nest products of stingless bee, Heterotrigona itama (Cockerell, 1918)

Stingless bee, Heterotrigona itama nest products which are propolis, honey, and bee bread are rich in antimicrobial activities which particularly limit the development of microorganisms. Regardless of the antimicrobial activities, some bacteria still can survive in nest products. To date, little is known about the bacterial species (other than lactic acid bacteria) in the nest products of H. itama. Therefore, the aim of this study was to isolate and characterise bacterial species (other than lactic acid bacteria) in the H. itama propolis, bee bread, and honey. The nest products were aseptically collected from four geographical localities of Malaysia. Total plate count (TPC), bacterial identification, phenotypic profile, enzymatic, and antimicrobial activities were studied. In this study, low levels of TPC were detected in the propolis, honey, and bee bread due to the reported antimicrobial activities of the nest products. The TPC originated from propolis ranges from 6.3 × 103 to 1.8 × 104 cfu/g, honey (0 to 8.0 × 103 cfu/g), and bee bread (0 to 1.1 × 104 cfu/g). Here, 41 isolates were obtained: propolis (18 isolates), bee bread (14 isolates), and honey (9 isolates) using spread plate method on nutrient agar. The 16S rDNA identification and further confirmation by phylogenetic tree analysis have found that the isolates belonged to the phylum Firmicutes, Proteobacteria, and Actinobacteria. Fifteen isolates with different identified species namely Bacillus oleronius PD3, Bacillus nealsonii PD4, Bacillus stratosphericus PD6, Bacillus amyloliquefaciens PD9, Bacillus toyonensis PD13, Bacillus subtilis BD3, Bacillus altitudinis BD4, Bacillus aryabhattai BD8, Bacillus safensis BD9, Bacillus cereus HD1, Bacillus pseudomycoides HM2, Enterobacter asburiae PD12, Enterobacter cloacae PM4, Pantoea dispersa PG1, and Streptomyces kunmingensis BG1 were used for phenotypic profile, enzymatic assays, and antimicrobial activity determination. The GENIII MicroPlateTM system revealed that the isolates were capable to utilise various carbohydrates, amino acids, and carboxylic acids. Proteolytic, lipolytic, and cellulolytic activities were detected from B. amyloliquefaciens PD9, B. stratosphericus PD6, B. subtilis BD3, and B. safensis BD9. Broad spectrum of antimicrobial activity was found from B. amyloliquefaciens PD9 that can inhibit Gram-positive and Gram-negative bacteria. This is the first study on the isolation and characterisation of bacterial species (other than lactic acid bacteria) from the Malaysian stingless bee, H. itama nest products. The characteristics of bacterial species associated with H. itama were investigated. The results suggested that the isolates might contribute to the formation of bee products by the enzymes and antimicrobial metabolites production.

Text FBSB 2019 14 - ir.pdf Download (1MB)

Actions (login required)

View Item