Physico-Chemical Analysis of Violacein Extracted from Various Strains of Chromobacterium violaceum

Brittany K Davis, Tennessee State University


Violacein is a violet pigment isolated from gram-negative Chromobacterium violaceum (CV). It has been reported to have bactericidal, tumoricidal, trypanocidal, and antileishmanial properties. Some researchers believe that by altering violacein's chemical structure, its biological activity would be enhanced. The main objective of this project was to determine the chemical differences between CV strains recovered from the Tennessee Copper Basin, using various spectroscopic methods and thin layer chromatography. Violacein was extracted from three various strains of Chromobacterium violaceum, purified by filtration, and analyzed by ultra-violet (UV) spectroscopy, infrared (IR) spectroscopy, Raman spectroscopy, and thin layer chromatography. During the TLC analysis, extract 14N23 and 14N1, both exhibited a greater amount of deoxyviolacein than violacein, in comparison to extract 12472; however, there was a greater amount of deoxyviolacein observed in extract 14N1 than in extract 14N23. These differences were also exhibited in the analyses using UV-VIS, IR, and Raman spectroscopy. A shift in wavelength and higher absorbance was observed in the U.V. spectrums of all the extracts. Extract 14N1 exhibited the greatest shift in wavelength. The IR and Raman spectrums revealed differences in the fingerprint region of extracts 12472 and 14N23. The IR spectrum of 14N1 did not consist of the O-H stretching band that was observed in the spectrums of 12472 and 14N23. Based on these results and the information reviewed in the literature, it was concluded that extract 14N23 and 14N1 produced more deoxyviolacein than violacein. Numerous factors could have affected the biosynthesis pathway of these products. Factors including the geographical location and the bioavailability of resources needed for the production of violacein could have caused of the increased production of deoxyviolacein. In order to determine how the production of violacein and deoxyviolacein vary between these extracts, an analysis using high performance liquid chromatography (HPLC) coupled with mass spectrometry should be used to determine the mass and quantity of each product.

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Recommended Citation

Brittany K Davis, "Physico-Chemical Analysis of Violacein Extracted from Various Strains of Chromobacterium violaceum" (2012). ETD Collection for Tennessee State University. Paper AAI1543746.