title: Olive pomace valorization by Aspergillus species: lipase production using solid-state fermentation.
abstract: BACKGROUND
  Pollution by olive mill wastes is an important problem in the Mediterranean area and novel solutions for their proper management and valorization are needed. The aim of this work was to optimize a solid-state fermentation (SSF) process to produce lipase using olive pomace (OP) as the main source of nutrients by several Aspergillus spp. Optimized variables in two different designs were: ratio between olive pomace and wheat bran (OP:WB), NaNO3 , Czapek nutrients, fermentation time, moisture content (MC) and temperature.
  
  
  RESULTS
  Results showed that the mixture OP:WB and MC were the most significant factors affecting lipase production for all fungi strains tested. With MC and temperature optimization, a 4.4-fold increase in A. ibericus lipase was achieved (90.5 ± 1.5 U g(-1) ), using a mixture of OP and WB at 1:1 ratio, 0.02 g NaNO3 g(-1) dry substrate, absence of Czapek nutrients, 60% of MC and incubation at 30 °C for 7 days. For A. niger and A. tubingensis, highest lipase activity obtained was 56.6 ± 5.4 and 7.6 ± 0.6 U g(-1) , respectively.
  
  
  CONCLUSIONS
  Aspergillus ibericus was found to be the most promising microorganism for lipase production using mixtures of OP and WB. © 2015 Society of Chemical Industry.
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Felisbela
authors.initials: F
authors.lastname: Oliveira
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Moreira
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Salgado
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Abrunhosa
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Armando
authors.initials: A
authors.lastname: Venâncio
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Belo
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D004043:Dietary Fiber; D005285:Fermentation; D007218:Industrial Microbiology; D007220:Industrial Waste; D008049:Lipase / Q000096:biosynthesis*; D031658:Olea
chemical_list: D004043:Dietary Fiber; D007220:Industrial Waste; D008049:Lipase
keywords: A. ibericus; A. niger; A. tubingensis; lipase production; olive pomace (OP); solid-state fermentation (SSF)