title: Response surface optimization of medium components for citric acid production by Aspergillus niger NRRL 567 grown in peat moss.
abstract: Aspergillus niger NRRL 567 was grown in an inert support material for citric acid production. Optimization of the medium components, including ethanol, methanol, phytate, olive oil and surfactant was carried out using "one-factor-at-a-time" and central composite design (CCD) methods. Optimization using "one-factor-at-a-time" was performed and the supplement of ethanol and methanol between 15 and 30 g/kg dry peat moss (DPM) enhanced citric acid production while higher levels than 30 g/kg DPM had an inhibitory effect on citric acid production at 48 and 72 h of incubation. Based on the results of "one-factor-at-a-time" optimization, phytate, olive oil and methanol were the selected additives to test the effect on citric acid production using CCD. The three variables were identified to have significant effects on citric acid production and the maximum citric acid production of 354.8 g/kg DPM was resulted from the combination of 19 g phytate/kg DPM, 49 g olive oil/kg DPM and 37 g methanol/kg DPM at 120 h. Maximum citric acid production in optimized condition by CCD represented about a 2.7-fold increase compared to that obtained from control before optimization.
authors.affiliation: Department of Bioresource Engineering, Faculty of Agricultural and Environmental Sciences, McGill University, Ste Anne de Bellevue, QUE, Canada.
authors.forename: Suzelle
authors.initials: S
authors.lastname: Barrington
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Kim
mesh_terms: D001234:Aspergillus niger / Q000502:physiology*; D019343:Citric Acid / Q000378:metabolism*; D003470:Culture Media; D007700:Kinetics; D000432:Methanol / Q000032:analysis; D000069463:Olive Oil; D010833:Phytic Acid / Q000032:analysis; D010938:Plant Oils / Q000032:analysis; D044003:Sphagnopsida / Q000382:microbiology*; D013499:Surface Properties
chemical_list: D003470:Culture Media; D000069463:Olive Oil; D010938:Plant Oils; D019343:Citric Acid; D010833:Phytic Acid; D000432:Methanol