title: Mussel processing wastewater: a low-cost substrate for the production of astaxanthin by Xanthophyllomyces dendrorhous.
abstract: BACKGROUND
  The use of astaxanthin in different industries such as the chemical, pharmaceutical, food, animal feed and cosmetic has been receiving increasing attention in recent years. Natural supplies of the pigment include crustacean by-products, algal, and microbial cultivation, being the yeast Xanthophyllomyces dendrorhous together with the alga Haematococcus pluvialis the most promising microorganisms for this bioproduction. Different vegetable by-products of the food industry have been explored so far as low-cost substrates for the production of astaxanthin by X. dendrorhous. This study focuses for the first time on the use of a low-cost formulated medium from a marine by-product, mussel-processing wastewater, for the production of astaxanthin by the yeast X. dendrorhous.
  
  
  RESULTS
  The yeast was able to grow in non-saccharified mussel broth, revealing the ability of the microorganism to hydrolyze glycogen. However, partial glycogen saccharification with α-amylase was needed for astaxanthin biosynthesis, obtaining maximal productions of 22.5-26.0 mg/L towards the end of the culture and coinciding with yeast highest amylolytic activity. Cultivations in totally-saccharified media revealed an increase in maximal cell concentrations and a decrease in maximal growth rates and astaxanthin production with increasing glucose initial concentration.
  
  
  CONCLUSIONS
  Astaxanthin production was higher in partially-saccharified mussel-processing waste than in synthetic medium (yeast peptone dextrose) containing glucose as carbon source (13 mg/L), suggesting this by-product is a promising nutritive medium for astaxanthin production. The use of this effluent also contributes towards the recycling and depuration of this highly pollutant effluent.
authors.affiliation: Grupo de Reciclado y Valorización de Residuos (REVAL), Instituto de Investigacións Mariñas (IIM-CSIC), R/Eduardo Cabello 6, 36208, Vigo, Spain. sabelara@uvigo.es.|Departamento de Química Analítica y Alimentaria, Facultad de Ciencias de Ourense, Universidad de Vigo, Campus As Lagoas s/n, Orense, Spain. sabelara@uvigo.es.
authors.forename: Isabel Rodríguez
authors.initials: IR
authors.lastname: Amado
authors.affiliation: Grupo de Reciclado y Valorización de Residuos (REVAL), Instituto de Investigacións Mariñas (IIM-CSIC), R/Eduardo Cabello 6, 36208, Vigo, Spain. jvazquez@iim.csic.es.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Vázquez
mesh_terms: D000818:Animals; D001487:Basidiomycota / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D049872:Bivalvia / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005947:Glucose / Q000378:metabolism; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology; D024341:Xanthophylls / Q000096:biosynthesis / Q000737:chemistry
chemical_list: D003470:Culture Media; D005947:Glucose; D062065:Wastewater; D024341:Xanthophylls; C005948:astaxanthine