ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Extraction and characterization of staphyloxanthin from Staphylococcus aureus as a natural alternative to synthetic food colorants

B. Lokeshwari, Ghassan J. K. Al-Abedi, Ashish Kumar Nayak, Thuraya Khaled Abdulwahed, Sagia Abbas Gibar Aifari, K. Gayathri, and P. Saranraj

PG and Research Department of Microbiology, Sacred Heart College (Autonomous), Tirupattur, India

E-mail: nashish.iitg@gmail.com

Received: 10 April 2026  Accepted: 4 June 2026

Abstract:

Staphylococcus aureus produces staphyloxanthin, a carotenoid pigment with coloring and bioactive properties was investigated here as a potential natural food colorant. The pigment-producing bacterium was isolated from tomato rhizosphere soil and presumptively identified via morphological and biochemical methods. Staphyloxanthin was extracted using a methanol–water mixture and filtered through a 0.22 µm membrane to remove viable bacterial cells, addressing biosafety on an experimental scale. The pigment was preliminarily confirmed by acidification-induced color shift from yellow to orange. UV–Vis, FT-IR, HPLC, LC–MS, and ¹H NMR analyses confirmed the carotenoid nature and structural features of the extracted pigment. The pigment showed concentration-dependent antioxidant (DPPH assay) and antibacterial activity against Gram positive and Gram negative pathogens (Inhibition zones: 10–17 mm). Optimal pigment production occurred at pH 8, 40 °C, 1% NaCl, with dextrose and yeast extract as best carbon and nitrogen sources. The pigment exhibited good color intensity under simulated thermal conditions, supporting its further evaluation as a food colorant. Due to the pathogenic origin of S. aureus, comprehensive toxicological evaluation and regulatory approval are required before food application. Staphyloxanthin shows potential as a sustainable, multifunctional natural pigment for further evaluation in food, pharmaceutical, and cosmetic applications. This study explored the extraction, characterization, and functional evaluation of staphyloxanthin from S. aureus as a potential natural food colorant.

Keywords: Staphyloxanthin; Staphylococcus aureus; Microbial pigments; Natural food colorants; Food stability

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05172-y

Chemical Papers 80 (11) 13185–13206 (2026)