Indo. J. Chem., 2013, 13 (3), 229 - 235 Venty Suryanti et al. 229 * Corresponding author. Tel/Fax : +62-271-663375 Email address : venty_s@yahoo.com PRODUCTION AND CHARACTERIZATION OF BIOSURFACTANT BY Pseudomonas fluorescens USING CASSAVA FLOUR WASTEWATER AS MEDIA Venty Suryanti*, Soerya Dewi Marliyana, Desi Suci Handayani, and Desi Ratnaningrum Department of Chemistry, Faculty of Mathematic and Natural Sciences, Sebelas Maret University Jl. Ir. Sutami 36A, Surakarta, Central Java 57126, Indonesia Received September 7, 2013; Accepted October 31, 2013 ABSTRACT Biosurfactant with efficient emulsification properties could be produced by Pseudomonas flourescens using cassava flour wastewater (manipueira) as media. The ability of P. flourescens to produce biosurfactant could suggest potential use in industrial and environmental applications. Media containing a mixture of natural manipueira and nutrient broth with 48 h fermentation was the optimum condition for the biosurfactant production. Based on UV- Vis and FT-IR spectra, the biosurfactant was indicated as rhamnolipids containing hydroxyl, ester, carboxylic and aliphatic carbon chain functional groups. Biosurfactant exhibited critical micelle concentration (CMC) value of 715 mg/L and reduced the surface tension of the water from 80 mN/m to 59 mN/m. The biosurfactant was able to decrease the interfacial tension about 51-70% when benzyl chloride, palm oil and kerosene were used as water- immiscible compounds. The biosurfactant was able to form stable emulsion until 30 days when paraffin, soybean oil, lubricant oil and kerosene were used as water-immiscible compounds. Keywords: biosurfactant; manipueira; Pseudomonas flourescens ; rhamnolipids ABSTRAK Biosurfaktan dengan sifat emulsifikasi yang baik dapat diproduksi oleh P. fluorescens menggunakan limbah industri tepung tapioka (manipueira) sebagai media. Kemampuan produksi biosurfaktan oleh P. fluorescens bisa diaplikasikan di industri dan untuk penyelesaian masalah lingkungan. Penggunaan campuran media nutrient broth dan manipueira tanpa perlakuan awal dengan lama fermentasi 48 jam merupakan kondisi optimum untuk produksi biosurfaktan. Analisa spektrofotometer UV-Vis dan FT-IR menunjukkan bahwa biosurfaktan merupakan rhamnolipida yang mempunyai gugus hidroksi, ester, karboksilat dan rantai alifatik. Biosurfaktan mempunyai nilai konsentrasi kritis misel (KKM) 715 mg/L dan mampu menurunkan tegangan permukaan air dari 80 mN/m ke 59 mN/m. Biosurfaktan ini dapat menurunkan tegangan muka sebesar 51-70% untuk senyawa hidrokarbon benzil klorida, minyak sawit dan kerosene. Biosurfaktan mampu membentuk emulsi yang stabil sampai 30 hari untuk senyawa hidrokarbon parafin, minyak kedelai, minyak pelumas dan kerosene. Kata Kunci: biosurfaktan; manipueira; Pseudomonas flourescens ; rhamnolipida INTRODUCTION Biosurfactants are a group of secondary metabolites with surface active properties and are synthesized by a great variety micro-organism. These metabolites are complex amphiphilic molecules whose hydrophobic and polar domains depend on the carbon substrate and bacterial strain. Biosurfactants have several advantages over the chemical surfactants, such as lower toxicity, higher biodegradability [1], better environmental compatibility [2], higher foaming [3], higher selectivity and specific activity at extreme temperatures, pH and salinity [4], and the ability to be synthesized from renewable feedstock [5]. In previous studies, we found that biosurfactants could be produced by P. aeruginosa using soybean oil as media [6]. The biosurfactant was identified as rhamnolipids and had the CMC of 860 mg/L and reduced the surface tension of the water from 72 mN/m to 52 mN/m. The biosurfactant could be used as an emulsifier to form emulsion between water and hydrocarbon such as palm oil, benzene, premium or toluene with various stability. The results indicated that biosurfactant could be used as an emulsifying and emulsion-stabilizing agent. Although productions of biosurfactants by several micro-organisms and their application have been reported [7-35], these compounds have not yet been employed extensively in industry because of their high production cost. The uses of low cost raw materials appear as a natural choice to process overall economy. Biosurfactant can be produced by microbial