A Photoexcited Porphyrin System as a Biomimetic Catalyst for D -limonene Biotransformation
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Catalysis Letters Vol. 105, Nos. 1–2, November 2005 ( 2005) DOI: 10.1007/s10562-005-8014-0
A photoexcited porphyrin system as a biomimetic catalyst for D-limonene biotransformation Mariusz Tryteka, Jan Fiedureka,*, Katarzyna Polskab, and Stanisław Radzkib a
Department of Industrial Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland b Faculty of Chemistry, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
Received 20 July 2005; accepted 2 August 2005
A photoexcited porphyrin system has been found to be an efficient catalyst for D-limonene biotransformation. The catalyst showed high selectivity in hydroxylation of D-limonene. The best catalyst for limonene biotransformation was 5,10,15,20Tetraphenylporphyrin (H2TPP), which gave the highest accumulation of carvone and an unknown product with a verbenone-like mass spectrum. The highest conversion yield of these products was favoured at 1:2 molar ratio of H2TPP to limonene. Some factors affecting the biotransformation yield were also investigated. Maximal yield of carvone was obtained in the medium containing 90% of the substrate, within the period of 18–36 h. Mechanism involved in limonene biotransformation catalysed by H2TPP is also discussed. KEY WORDS: biomimetic oxidation catalysts; biotransformation; D-limonene; porphyrin; uv–vis spectroscopy; photooxidation.
1. Introduction The preparation, characterisation, and use of new catalysts as the analogues of the active sites in metalloenzymes (design, synthesis, structure, and catalytic activity) is a research area currently named ‘‘biomimetic catalysis’’. The interest in the use of metalloporphyrins in biomimetic catalysis has been constantly growing during the last decades, as enzymology studies have been showing the role of these complexes as prosthetic groups of various transition metals containing enzymes (cytochromes P-450, peroxidases, and catalase) [1–3]. In particular, a number of research groups have focused their interest on the ability of metal porphyrins to catalyse redox processes in organic and inorganic compounds [4–7] In recent years, a number of authors have reported some examples of catalytic systems based on the use of photoexcited FeIIIporphyrins that can induce hydrocarbon oxygenation under aerobic conditions [4,5]. In pure cyclohexane, high yields of cyclohexanone with small amounts of cyclohexanol as a by-product were obtained [6]. Other alkanes can also be successfully oxidised to the corresponding ketones. [4,7]. In the literature, only a few reports concerning the transformation of limonene into limonene epoxide by manganase porphyrins can be found [8,9]. Terpenes, widely distributed in nature, constitute suitable precursor substrates for potential production of valuable natural flavour and fragrance compounds. * To whom correspondence should be addressed. E-mail: fi[email protected]
Monoterpenes, as substrates of microbial transformations, have led to a great variety of oxyfunctionalised compounds [10,11]. Among various mono
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