Microbial bioconversion of feathers into antioxidant peptides and pigments and their liposome encapsulation.

OBJECTIVES: The co-encapsulation of bioactive peptides obtained from degradation of chicken feathers and flexirubin-type pigment produced by Chryseobacterium sp. kr6 into phosphatidylcholine liposomes was investigated. RESULTS: Control empty liposomes showed mean diameter of 168.5 nm, varying to 185.4, 102.0 and 98.5 nm after the encapsulation of peptides, pigment and their co-encapsulation, respectively. Control liposomes presented zeta potential of - 20.9 mV, while the formulations containing the bioactive compounds showed values of - 30 mV or higher in magnitude. Infrared analysis revealed typical spectra for phosphatidylcholine, suggesting that no new chemical bonds were formed after encapsulation. ABTS radical scavenging assay showed that the antioxidant activity of the compounds was maintained after encapsulation. CONCLUSIONS: Feather waste can be a valuable substrate for simultaneous production of antioxidant peptides and pigment by Chryseobacterium sp. kr6, and their encapsulation into liposomes may be a suitable alternative for delivery of these natural antioxidants.

Extraction and partial characterisation of antioxidant pigment produced by Chryseobacterium sp. kr6.

Pigments synthesised by Chryseobacterium sp. kr6 growing on feather waste were extracted and characterised. The pigment extract was characterised by KOH test, UV-vis, CIELAB colour system, HPLC-DAD-MS, FTIR and its antioxidant capacity was evaluated. A positive bathochromic shift was observed when kr6 colonies or pigment extracts were subjected to alkaline solution (20% KOH) and a λmax at 450 nm was detected for acetone extracts, although no typical fine structure of carotenoids was detected in the electomagnetic spectra. The HPLC profile of the extracted pigment showed that the compound has three different peaks with λmax near 450 nm. The FTIR analysis shows some principal functional groups from a flexirubin-like molecule. The pigmented compound also presents antioxidant activity evaluated by the scavenging of the ABTS radical.

Chryseobacterium piscicola sp. nov., isolated from diseased salmonid fish.

Eight bacterial strains isolated from diseased rainbow trout (n=5) and Atlantic salmon (n=3) were characterized by phenotypic and molecular taxonomic methods. The isolates were negative for the Gram-reaction, non-motile, rod-shaped and catalase- and oxidase-positive. Colonies on solid media were yellow, smooth, shiny and circular with regular edges. Growth occurred at 4-28 degrees C (optimum, 15 degrees C) and with 0-3 % NaCl (optimum, 0.5 %). Analysis of the 16S rRNA gene sequence allocated the micro-organisms to the genus Chryseobacterium, with Chryseobacterium soldanellicola PSD1-4(T) and Chryseobacterium soli JS6-6(T) as their closest relatives (96.9 and 97.1 % sequence similarity, respectively). The levels of DNA-DNA hybridization towards these nearest phylogenetic neighbours were below 17.1 %. The DNA G+C contents of strains VQ-6316s(T) and VQ-4836s were 32.5 and 32.3 mol%, respectively. The predominant menaquinone was MK-6 and the major fatty acids were iso-C(15 : 0), anteiso-C(15 : 0), iso-C(17 : 1)omega9c, iso-C(17 : 0) 3-OH and summed feature 3 (comprising C(16 : 1)omega7c and/or C(16 : 1)omega7t and/or iso-C(15 : 0) 2-OH). The eight isolates were classified as representatives of a novel species, Chryseobacterium piscicola sp. nov., with strain VQ-6316s(T) (=CECT 7357(T)=DSM 21068(T)) as the type strain.