Open AccessInulinolytic activity of broths of Aspergillus niger ATCC 204447 cultivated in shake flasks and stirred tank bioreactor
Author(s) -
Kowalska Anna,
Antecka Anna,
Owczarz Piotr,
Bizukojć Marcin
Publication year - 2017
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201600247
Subject(s) - bioreactor , aeration , laboratory flask , aspergillus niger , pellets , chemistry , biomass (ecology) , food science , continuous stirred tank reactor , aspergillus awamori , spore , chromatography , fermentation , botany , biology , organic chemistry , agronomy , paleontology
It is the first detailed study of an inulinolytic fungus Aspergillus niger ATCC 204447 since its discovery, covering submerged cultivations both in shake flasks and a stirred tank bioreactor. Various carbon sources were applied to induce the inulinolytic activity in shake flask cultures. The highest volumetric and specific (per gram of biomass) activities (respectively 0.68 U/mL and 184 U g/X) were observed for the initial inulin and sucrose concentrations equal to 20 g/L. The fungus grew as large (>3 mm) spherical pellets. The influence of inoculum density and application of microparticle‐enhanced cultivation (MPEC) were studied in the batch bioreactor cultivations. Inoculum density moderately affected the inulinolytic activities, whose highest values were 0.7 U/mL and 165 U g/X at the lowest studied spore density of 3.33·10 8 L −1 . Dispersed hyphae evolved in the bioreactor made the broth difficult to aerate due to high apparent viscosity (exceeding 200 Pa s n at shear rate about 0.05 s −1 ) and shear thinned properties (flow behavior index below 0.2). In MPEC (10 μm talc microparticles) the pellets of diameter between 1 and 2 mm were formed, which facilitated the aeration of the broth and increased the specific inulinolytic activity 3.5‐fold.