Bacillus amyloliquefaciens TSBSO 3.8, a biosurfactant-producing strain with biotechnological potential for microbial enhanced oil recovery
Vanessa Marques Alvarez, Diogo Jurelevicius, Joana Montezano Marques, Pamella Macedo de Souza, Livia Vieira de Ara˙jo, Thalita Gonšalves Barros, Rodrigo Octavio Mendonša Alves de Souza, Denise Maria GuimarŃes Freire, Lucy Seldin
Laboratório de Genética Microbiana, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Brazil.
A screening for biosurfactant-producing bacteria was conducted with 217 strains that were isolated from environmental samples contaminated with crude oil and/or petroleum derivatives. Although 19 promising biosurfactant producers were detected, strain TSBSO 3.8, which was identified by molecular methods as Bacillus amyloliquefaciens, drew attention for its production of a high-activity compound that presented an emulsification activity of 63% and considerably decreased surface (28.5 mN/m) and interfacial (11.4 mN/m) tensions in Trypticase Soy Broth culture medium. TSBSO 3.8 growth and biosurfactant production were tested under different physical and chemical conditions to evaluate its biotechnological potential. Biosurfactant production occurred between 0.5% and 7% NaCl, at pH values varying from 6 to 9 and temperatures ranging from 28 to 50°C. Moreover, biosurfactant properties remained the same after autoclaving at 121°C for 15 min. The biosurfactant was also successful in a test to simulate microbial enhanced oil recovery (MEOR). Mass spectrometry analysis showed that the surface active compound was a surfactin, known as a powerful biosurfactant that is commonly produced by Bacillus species. The production of a high-efficiency biosurfactant, under some physical and chemical conditions that resemble those experienced in an oil production reservoir, such as high salinities and temperatures, makes TSBSO 3.8 an excellent candidate and creates good expectations for its application in MEOR.
Keywords: Biosurfactant; Bacillus amyloliquefaciens; Surfactin; Microbial enhanced oil recovery (MEOR).