Surface Activity of Surfactin Recovered and Purified from Fermentation Broth Using a Two-Step Ultrafiltration (UF) Process

• Main Authors: Mohd Hafez, Mohd Isa, A. Richard, Frazier, Paula, Jauregi
• Format: Article
• Language: en_US
• Published: Universiti Kebangsaan Malaysia 2015
• Subjects: Beta Casein (Beta-Casein); Bovine Serum Albumin (BSA); Critical Micelle Concentration (CMC); Surfactin
• Online Access: http://ddms.usim.edu.my/handle/123456789/8431
• Institution: Universiti Sains Islam Malaysia

B. subtilis under certain types of media and fermentation conditions can produce surfactin, a biosurfactant which belongs to the lipopeptide class. Surfactin has exceptional surfactant activity, and exhibits some interesting biological characteristics such as antibacterial activity, antitumoral activity against ascites carcinoma cells, and a hypocholesterolemic activity that inhibits cAMP phosphodiesterase, as well as having anti-HIV properties. A cost effective recovery and purification of surfactin from fermentation broth using a two-step ultrafiltration (UF) process has been developed in order to reduce the cost of surfactin production. In this study, competitive adsorption of surfactin and proteins at the air-water interface was studied using surface pressure measurements. Small volumes of bovine serum albumin (BSA) and beta-casein solutions were added to the air-water interface on a Langmuir trough and allowed to stabilise before the addition of surfactin to the subphase. Contrasting interfacial behaviour of proteins was observed with beta-casein showing faster initial adsorption compared to BSA. On introduction of surfactin both proteins were displaced but a longer time were taken to displace beta-casein. Overall the results showed surfactin were highly surface-active by forming a beta-sheet structure at the air-water interface after reaching its critical micelle concentration (CMC) and were effective in removing both protein films, which can be explained following the orogenic mechanism. Results showed that the two-step UF process was effective to achieve high purity and fully functional surfactin.