The Effect of Molasses Concentration and Incubation Time in
Biosurfactant Production by Azotobacter chroococcum
Fatimah, Marinda Dwi Yurdahayu, & Ni’matuzahroh
Department of Biology, Faculty of Science and Technology, University of Airlangga,
Kampus C, Jln. Mulyorejo, Surabaya-60115, Indonesia
e-mail: fatimah@unair.ac.id
This research was aimed to know the effect of molasses concentration, incubation time and the
best combination to biosurfactant production by Azotobacter chroococcum. Growth media consists of
mineral synthetic water with different concentrations of molasses (0%, 2,5%, 5%, and 7,5%). 10% of
Azotobacter chroococcum starter (OD= 0,5, λ= 500 nm) was inoculated into each media and incubated
in a shaker at 120 rpm and 280 C with different incubation times (0, 1, 2, 3, and 4 days). Biosurfactant
production was observed by measuring emulsification activity and surface tension reduction of
supernatant. Solar and kerosene were used to determine emulsification activity. The results of this
research showed that molasses concentration and incubation time influenced biosurfactant production.
Molasses concentration 7,5% (v/v) with 3 days incubation time was the best combination in
biosurfactant production which indicated by surface tension reduction up to 6,33 dyne/cm and
emulsification activity 24 hours up to 40,37% (solar) and 36,70% (kerosene).
Key words :
biosurfactant, Azotobacter chroococcum, molasses, incubation time, emulsification
activity, surface tension