FEMS MicrobiologyLetters 43 (1987) 33-37 33 Published by Elsevier FEM 02793 Streptococcal oxidation of malvin: the role peroxidogenic bacteria can play in decolorization J. Ptrez, J. Paredes, M. Monteoliva-S~nchez, E. Moreno, A. Ramos-Cormenzana and J. Martinez Department of Microbiology, Facultyof Pharmacy, Universityof Granada, Granada, Spain Received 27 November1986 Accepted 12 February 1987 Key words: Anthocyanin; Oxidation; Hydrogen peroxide; Streptococcus durans; Malvin; Biodegradation 1. SUMMARY The possible use of microorganisms which yield substantial levels of hydrogen peroxide in treat- ments for decolorization of a natural pigment (malvidin-3,5-diglucoside) was studied. Streptococ- cus durans S-76 was able to oxidize about 38% malvin implicating biogenic hydrogen peroxide in a buffered solution. Malvin by-products and the coumarinic derivative have identical properties and high-performance liquid chromatographic pat- terns. 2. INTRODUCTION Anthocyanic pigments are being screened as natural food colourants, and they are also sub- stances which contribute to the high polluting effect of waste waters from olive oil-extracting plants. It will be interesting to find alternative meta- boric routes for the degradation of complex organic Correspondence to: J. Ptrez, Department of Microbiology,Fa- culty of Pharmacy, University of Granada, 18001 Granada, Spain. molecules. We have studied the influence of a hyperperoxidogenic bacterium on the structure of an anthocyanin (malvin) (Fig. 1). This treatment degrades malvin to the coumarinic derivative (Fig. 1). 3. MATERIALS AND METHODS 3.1. Microorganisms Streptococcus durans S-76 was supplied by the Department of Microbiology of the Faculty of Sciences of Granada (Spain). This strain was selected because it rapidly accumulates relatively high concentrations of hydrogen peroxide in cul- ture media, inhibiting the growth of other bacteria [11. 3.2. Bacterial growth and 1t202 accumulation Centrifuge tubes containing 4 ml of a culture medium: Casitone-Difco 15 g, Bacto-Peptone- Difco 5 g, NaC1 5 g, Na2HPO 4 2.18 g and NaH2PO 4 0.5 g per liter (pH 7) were inoculated (10% each) with S. durans S-76 after an overnight incubation at 28 ° C. After 24 h of anaerobic in- cubation (Gaspak Anaerobic systems BBL) at the same temperature, the cultures were centrifuged at 0378-1097/87/$03.50 © 1987 Federation of European MicrobiologicalSocieties Downloaded from https://academic.oup.com/femsle/article-abstract/43/1/33/532068 by guest on 06 June 2020