Clavispora apidarum f.a., sp. nov., a novel yeast species from the gut of a stingless bee (Hymenoptera – Apidae) producing a biosurfactant with antimicrobial activity

Introduction Insect-associated yeasts represent a potential source of novel species and bioactive compounds. This study investigated the taxonomy and biosurfactant-producing potential of a yeast strain isolated from the gut of stingless bee. Methods Twenty-seven yeast strains were isolated from insects that were collected from the garden of CSIR-Institute of Microbial Technology, Chandigarh, India. Identification and phylogenetic analyses were performed using D1/D2 domain sequences of the large subunit ribosomal RNA gene. Biosurfactant production was evaluated by surface tension measurement, FTIR, and LC-MS, while antimicrobial activity was assessed against selected bacteria. Results Twenty-six isolates belonged to previously described yeast species, whereas strain IIG-5W T represented a putative novel species related to the genus Clavispora . It exhibited 15.7–18.11% sequence divergence from the closely related described species. The closest undescribed relative, Candida sp. MD122, differed by 1.4%. Strain IIG-5W T produced a surface-active biosurfactant. LC-MS analysis revealed a peak at m/z 688, tentatively assigned to diacetylated acidic sophorolipid Ac 2 LS C 18:1 . The sophorolipid fraction demonstrated promising antimicrobial activity against selected Gram-positive and Gram-negative bacteria. Conclusion Strain IIG-5W T is proposed as Clavispora apidarum f.a., sp. nov. The holotype is CBS 16296 T , with MTCC 12980 T and KCTC 37022 T as isotypes (MycoBank MB834100).