title: Hydrolytic enzymes production by Aspergillus section Nigri in presence of butylated hydroxyanisole and propyl paraben on peanut meal extract agar.
abstract: BACKGROUND
  In the last years, food grade antioxidants are used safely as an alternative to traditional fungicides to control fungal growth in several food and agricultural products.
  
  
  OBJECTIVE
  In this work, the effect of butylated hydroxyanisole (BHA) and propyl paraben (PP) on two hydrolytic enzyme activity (β-d-glucosidase and α-d-galactosidase) by Aspergillus section Nigri species under different water activity conditions (aW; 0.98, 0.95 and 0.93) and incubation time intervals (24, 48, 72 and 96h) was evaluated on peanut-based medium.
  
  
  METHODS
  The activity of two glycosidases, β-d-glucosidase and α-d-galactosidase, was assayed using as substrates 4-nitrophenyl-β-d-glucopyranosido and 4-nitrophenyl-α-d-galactopyranosido, respectively. The enzyme activity was determined by the increase in optical density at 405nm caused by the liberation of p-nitrophenol by enzymatic hydrolysis of the substrate. Enzyme activity was expressed as micromoles of p-nitrophenol released per minute.
  
  
  RESULTS
  The major inhibition in β-d-glucosidase activity of A. carbonarius and A. niger was found with 20mmoll(-1) of BHA or PP at 0.98 and 0.95 aW, respectively, whereas for α-d-galactosidase activity a significant decrease in enzyme activity with respect to control was observed in A. carbonarius among 5 to 20mmoll(-1) of BHA or PP in all conditions assayed. Regarding A. niger, the highest percentages of enzyme inhibition activity were found with 20mmoll(-1) of BHA or PP at 0.95 aW and 96h.
  
  
  CONCLUSIONS
  The results of this work provide information about the capacity of BHA and PP to inhibit in vitro conditions two of the most important hydrolytic enzymes produced by A. carbonarius and A. niger species.
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Member of the Research Career of CONICET (CIC-CONICET), Argentina.
authors.forename: Carla L
authors.initials: CL
authors.lastname: Barberis
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Fellowship of the CONICET, Argentina.
authors.forename: María F
authors.initials: MF
authors.lastname: Landa
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Fellowship of the CONICET, Argentina.
authors.forename: Mauricio G
authors.initials: MG
authors.lastname: Barberis
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Fellowship of the CONICET, Argentina.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Giaj-Merlera
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Member of the Research Career of CONICET (CIC-CONICET), Argentina.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Dalcero
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Member of the Research Career of CONICET (CIC-CONICET), Argentina. Electronic address: cmagnoli@exa.unrc.edu.ar.
authors.forename: Carina E
authors.initials: CE
authors.lastname: Magnoli
mesh_terms: D000362:Agar; D000975:Antioxidants / Q000494:pharmacology*; D010367:Arachis; D001230:Aspergillus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D001234:Aspergillus niger / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D002083:Butylated Hydroxyanisole / Q000494:pharmacology*; D003470:Culture Media; D004790:Enzyme Induction / Q000187:drug effects; D005520:Food Preservatives / Q000494:pharmacology*; D005656:Fungal Proteins / Q000096:biosynthesis*; D010226:Parabens / Q000494:pharmacology*; D010936:Plant Extracts; D013696:Temperature; D013997:Time Factors; D014867:Water; D000519:alpha-Galactosidase / Q000096:biosynthesis*; D001617:beta-Glucosidase / Q000096:biosynthesis*
chemical_list: D000975:Antioxidants; D003470:Culture Media; D005520:Food Preservatives; D005656:Fungal Proteins; D010226:Parabens; D010936:Plant Extracts; D014867:Water; D002083:Butylated Hydroxyanisole; D000362:Agar; D001617:beta-Glucosidase; D000519:alpha-Galactosidase; C006068:propylparaben
keywords: Aspergillus carbonarius; Aspergillus niger; Butylated hydroxyanisole; Enzimas hidrolíticas; Hidroxianisol butilado; Hydrolytic enzymes; Propilparabeno; Propyl paraben; Valores de actividad acuosa; Water activities