author(s)
Nagarathinam Arunkumar, Jainullabudeen Gulsar Banu, Nagarajan Gopalakrishnan and Arkalgud Hiriyannaiah Prakash

abstract
The physiological role of microbial surfactants production in microorganisms includes antimicrobial activity and break down of complex hydrocarbon substances to make the substrates readily available for uptake in adverse environmental conditions. Wax degrading bacteria are a significant group of microorganisms facilitated mainly by the production of microbial surfactants to emulsify waxy substances. Bacterial strains isolated from cotton mealybugs were screened for biosurfactant production. Eight strains (PSAD 1, PSAD 2, PSAD 3, PSAD 5, PSAD 6, PSAD 7, PSAD 8 and PSAD 9) isolated from the carcass of mealybug species, Phenacoccus solenopsis (Tinsley) and Ferrisia virgata (Cockerell) showed positive results. Among all the isolates, PSAD 2 and PSAD 7 showed maximum biosurfactant potential of 142.14 mm² and 115.93 mm², respectively. Based on morphological and biochemical profiles, the isolates were tentatively identified belonging to the genera Bacillus, Enterobacter, Pseudoxanthomonas, Pseudomonas and Serratia. The results clearly confirmed the ability of the WDB isolates to utilize wax substrates through microbial surfactants production.