Screening and Characterization of bio-surfactant producing Bacillus spp. from milk samples
Sanjana MC, Shivalkar Yadav K, Jayashri P Hiremath, Prabha R
Biosurfactants are surface metabolites produced by many bacteria, amphiphilic in nature. Preliminary and specific tests were carried out for 23 biosurfactant producing Bacillus isolates to characterize up to species level. Preliminary tests like Gram’s staining,bacterial spore staining, catalase, and oxidase confirmed the genus as Bacillus while specific tests helped to determine the species of Bacillus. As per the phenotypic identification of biosurfactant producing 23 isolates of Bacillus species from 6 milk samples (3 fresh and 3 spoiled), 13 isolates were identified as Bacillus licheniformis and 10 isolates as Bacillus subtilis. All the 23 isolates of Bacillus species when grown in sterile nutrient broth at 370C for 24 h for screening and confirmation of surfactant production, 10 isolates showed direct microscopic count (DMC) ranging from 7.0 to 7.5 log10/ml with spreading of butter oil of 1 to 2 mm., while 13 numbers had DMC between 8 and 8.6 log10 /ml while oil spreading diameter ranged from 3 to 5 mm, respectively. Among 23 isolates, B16 showed highest DMC of 8.6 log10/ml with higher oil spreading ability of 5 mm diameter. Isolate B16 identified as B. licheniformis phenotypically once showed higher DMC and oil spreading ability, that isolate was genotyped to confirm identity as B. licheniformis with accession number KY3233391.
Sanjana MC, Shivalkar Yadav K, Jayashri P Hiremath, Prabha R. Screening and Characterization of bio-surfactant producing Bacillus spp. from milk samples. International Journal of Educational Research and Development, Volume 1, Issue 4, 2019, Pages 07-12