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PRODUCTION OF ANTIBACTERIAL COMPOUNDS BY FREE AND IMMOBILIZED BACILLUS PUMILUS SAF1

FARIHA HASAN, SAMIULLAH KHAN, AAMER ALI SHAH^* AND ABDUL HAMEED

Abstract: In the present study, Bacillus pumilus SAF1, capable of producing antimicrobial compounds, was indigenously isolated from soil. Antimicrobial substances were found to be produced by Bacillus pumilus SAF1 against Micrococcus luteus (ATCC # 10240) and Staphylococcus aureus (ATCC # 6538) used as test organisms. Maximum production of antimicrobial compounds by Bacillus pumilus SAF1, was observed at pH 7, 3% glucose and after 48 hours of incubation at 30^oC, on the basis of zones of inhibition against Micrococcus luteus (ATCC # 10240) and Staphylococcus aureus (ATCC # 6538). Whole cells of Bacillus pumilus SAF1 were immobilized in polyacrylamide gel, sodium alginate and agar-agar, and checked for antibiotic production by Agar Diffusion Assay, against Micrococcus luteus (ATCC # 10240) and Staphylococcus aureus (ATCC # 6538), and various parameters [pH (6-9), incubation period (0-72 hours) and glucose concentration (1-5%)] were optimized for maximum production of antibiotics. Maximum activity in the form of zone of inhibition (32mm) was observed at pH 7, 3% glucose, and after 72 hours of incubation in polyacrylamide gel. As a whole, the antimicrobial activity was higher in sodium alginate and agar-agar as compared to free cells fermentation. As the activity of antibiotic production increased in case of immobilized cells, so it can be concluded that in the present study, immobilization proved to be a better process, as compared to production of antibiotic from free cell.

Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan

Corresponding author E-mail: alishah_75@yahoo.com; Tel. No. +92-51-90643065; Fax No. +92-51-9219888