Production and Characterization of Biosurfactants by Candida boleticola H09 and Rhodotorula bogoriensis H15 for crude oil recovery and cleaning of oil contaminated fabrics

Abstract

The production and characterization of biosurfactant by Candida boleticola H09 and Rhodotorula bogoriensis H15 were examined in this study. Seven agro-waste substrates (corn cob, cassava effluent, maize bran, rice straw, banana peels, corn husk and sugar cane bagasse) were used for yeast growth. The substrates supported yeast growth with banana peels having the highest optical density (OD) of 0.704 for S. cerevisiae H02; 0.417 for C.boleticola H09 and 0.458 for R. bogoriensis H15. This was followed by corn husk, maize bran and cassava effluent. These four substrates, which supported growth of yeasts were used in biosurfactants production by the yeasts. The result revealed that R. bogoriensis H15 had the highest yield of 2.62 g/l on corn husk, 2.02 g/l on maize bran, 1.16 g/l on cassava effluent and 0.5 g/l on banana peels. Chemical characterization of the biosurfactants was done using GC-MS and the results obtained indicated that they were glycolipids composed of palmitic hexadecanoic, octadecanoic acids, methyl esters and hydroxylated fatty acids linked to a decanoic acid. Fourier transform infrared (FTIR) analysis showed that the surfactants consisted of carboxyl, hydroxyl and sugar derivative groups. Specifically, C. boleticola H09 and R. bogoriensis H15 produced biosurfactants designated as lactonic sophorolipid Bios-H09 and acid sophorolipid Bios-H15 respectively. The potentials of the biosurfactants to serve as detergent additive as well as detergent was evaluated on a white cotton cloth soiled with 3 ml motor oil using shake flask method. So-Klin detergent had 66.15 % wash followed by mixture of So-Klin and Bios-H09 (58.8 %), So-Klin and Bios-H15 (28 %), Bios-H09 (24.7 %), Bios-H15 (15.8 %) and distilled water (4 %). The potential of the biosurfactant to enhance crude oil recovery was also examined using sand pack column method. Bios- H09 enhanced oil recovery of 47.75 %, Bios-H15 recovered 32.25 % and distilled water (control) recovered 15.25 % of crude oil. The results suggest that C. boleticola H09 and R. bogoriensis H15 are good candidates for the production of biosurfactants, particularly sophorolipids that can be used for enhanced oil recovery.