Abstract
Microemulsions (ME) can act as a reservoir of solubilized hydrophobic substrates. The biotransformation of hydrophobic sitosterol to androstenedione (AD) with MEs prepared from nutrient broth and PEG 200 (1:1) as aqueous phase, 40 g/l sitosterol dissolved in chloroform as organic phase, Triton X114 and Tween 80 (1:1) as surfactant phase, was investigated. The phase behavior of this system was studied for ten different ratios(w/w), 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9 and 0:10 of the organic phase and surfactant at 30 °C. A pseudoternary phase diagram was constructed to demarcate the region giving stable MEs. The maximum solubility of sitosterol in ME medium was observed to be 8 g/l, which is 3 orders of magnitude higher than the reported sitosterol solubility of 2–4 mg/l in aqueous medium. The ME medium was used for biotransformation studies and a comparative result has been reported. Transmission electron microscopy of cells grown in ME having oil, surfactant and aqueous phase in the ratio of 6:14:80 showed a weakened cell wall structure that permitted production of 465.86 mg/l AD.
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References
Cruz A, Fernandes P, Cabral JMS, Pinheiro HM (2004) Solvent partitioning and whole cell sitosterol bioconversion activity in aqueous-organic two-phase system. Enzyme Microb Technol 34:342–353
Fraud S, Hann AC, Maillard JY, Russell AD (2003) Effects of ortho-phthalaldehyde, glutaraldehyde and chlorohexidine diacetate on Mycobacterium chelonae and Mycobacterium abscessus strains with modified permeability. J Antimicrob Chemother 51:575–584
Fernandes P, Cabral JMS, Pinheiro HM (1998) Influence of some operational parameters on the bioconversion of sitosterol with immobilized whole cells in organic medium. J Mol Catal B Enzym 5:307–310
Laane C, Boeren S, Vos K, Veeger C (1987) Rules for optimization of biocatalysis in organic solvents. Biotechnol Bioeng 30:81–87
Prichanont S, Leak DJ, Stuckey DC (2000) The solubilisation of mycobacterium in a water in oil microemulsion for biotransformations: system selection and characterization. Colloids Surf A Physicochem Eng Asp 166:177–186
Prichanont S, Leak DJ, Stuckey DC (2000) Chiral epoxide production using mycobacterium solubilised in a water-in-oil microemulsion. Enzyme Microb Technol 27:134–142
Smolders AJJ, Pinheiro HM, Noronha P, Cabral JMS (1991) Steroid biotransformation in a microemulsion system. Biotechnol Bioeng 38:1210–1217
Stefanov S, Yankov D, Beschkov V (2006) Biotransformation of phytosterols to androstenedione in two phase water-in-oil systems. Chem Biochem Eng Q 20(4):421–427
Wang Z, Zhao F, Hao X, Chen D, Li D (2004) Microbial Transformation of hydrophobic compound in cloud point system. J Mol Catal B Enzym 27:147–153
Wang Z, Hao X, Chen D (2008) Whole cell microbial transformation in cloud point system. J Ind Microbiol Biotechnol. doi: 10.1007/s10295-008-0345-6.
Acknowledgments
Research fellowship from the Council of Scientific and Industrial Research (CSIR) is deeply acknowledged by A. Malaviya. A partial grant from IIT Delhi and travel grant from Department of Biotechnology (DBT), Government of India, was received for attending BioMicroworld 2007. TEM facility was provided by SAIF, AIIMS, New Delhi.
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Malaviya, A., Gomes, J. Nutrient broth/PEG200/TritonX114/Tween80/Chloroform microemulsion as a reservoir of solubilized sitosterol for biotransformation to androstenedione. J Ind Microbiol Biotechnol 35, 1435–1440 (2008). https://doi.org/10.1007/s10295-008-0444-4
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DOI: https://doi.org/10.1007/s10295-008-0444-4