Isolation and characterization of biosurfactants-producing bacteria isolated from palm oil industry and evaluation for biosurfactants production โดย ดร.กนกรัตน์ ใสสอาด
Biosurfactants-producing bacteria were isolated from various palm oil refinery industrial sites in the south of Thailand.
Isolates were screened for biosurfactant production by using low-cost, agro-industrial by-products or wastes
as a substrate. Based on drop collapsing test and emulsification activity, 25 isolates were selected. All the selected
isolates reduced the growth medium surface tension to 40 mN/m and produced emulsions with xylene. Twenty
isolates exhibited high emulsion-stabilizing capacity, maintaining more than 50% of the original emulsion volume
for 24 h. The phylogenetic position of these 25 isolates was evaluated by 16S rRNA gene sequence analysis.The
production of biosurfactants was determined for strains representative of 15 different bacterial genera, six of them
(Azorhizobium, Buttiauxella, Comamonas, Halopenitus, Haloplanus and Sinorhizobium ) have been for the first time
reported in this study as biosurfactant-producing strains. Additionally, Sinorhizobium meliloti AS91 and Marinobacter
hydrocarbonoclasticus AS51 produced extracellular biosurfactant which exhibited the lowest surface tension
(32 mN/m) and emulsification activity (69%) when cashew apple juice and used vegetable oil were used as the carbon
source, respectively. Overall, this is the first study of a phylogenetic analysis of biosurfactant-producing bacteria
from palm oil refinery industry site and their ability to produce biosurfactant on renewable substrates.