Identification of carotenoid pigments in Bacillus licheniformis Rt4M10 isolated from roots of Vitis vinifera

COHEN A C; DICHIARA E; BOTTINI R; PICCOLI P N

La Falda

Workshop; II Latin American PGPR workshop; 2014

II PGPR Latinoamérica

Introduction Carotenoids are the most widespread naturally occurring yellow, orange and red pigments formed by the condensation of isoprenyl units. Carotenoids are synthesized by all photosynthetic organisms, as well as some bacteria and fungi. Due to their useful biological activities (antioxidant, UV protecting and natural food colorant properties), carotenoids are commercially used as food colorants and animal feed supplements, and more recently, they are being used as nutraceuticals and cosmetic and pharmaceutical compounds. Now, commercial carotenoid production is mostly carried out chemical synthesis or by extraction from plant tissues; however, microbial production also has great potential in terms of both efficiency and production. In a previous study B. licheniformis Rt4M10 was isolated from roots of Vitis vinifera L. (cv. Malbec) and induce abscisic acid accumulation and synthesis of defense-related terpenes in in vitro cultured grapevine. The aim of this study was to identify and quantify carotenoids produced by B. licheniformis Rt4M10 in LB medium with and without diphenylamine (DPA). Materials and methods The carotenoid pattern was characterized in response to DPA, an inhibitor of ketocarotenogenesis B. licheniformis Rt4M10 with and without DPA (100 µM) was cultivated aerobically for 4 and 7 days at 30 °C and 120 rpm in orbital shaker in dark. Cells were harvested by centrifugation at 7000 rpm at 4 °C for 5 min. The upper layer was discarded and residual cells were extracted with MeOH/CH3COCH3 (7:3, v/v) overnight at 4 °C. Suspensions were sonicated 10 min and centrifuged. The pigments separated by HPLC (high-performance liquid chromatography) equipped with a diode array detector. Finally, the carotenoids levels were quantified and identified based on the retention time (Rt) and absorption spectrum. Commercial 8-Apocarotenal (Sigma, St. Louis, MO, USA) was used as standard. Results The maximum concentration and diversity of carotenoids were founded at 4 days (licopene, δ-and β-carotene, β-criptoxantine, violaxanthin y zeaxanthin and four different compounds unidentified). In medium with DPA, the production was different (β-criptoxantine, β-carotene, zeaxanthin). At 7 days only 4 four different compounds unidentified were determinate (I-IV) while with DPA (δ-carotene, β-criptoxantine and zeaxanthin) were identified. Conclusion In this work we identified and demonstrated the production of different carotenoids by the strain B. licheniformis Rt4M10 which will be promising microorganisms for the commercial production. Areas temáticas propuestas: Taxones PGPR [Bacillales, Azospirillum, Pseudomonas, actinomycetes, y otros] [1] o Biotecnología [4]