caa a22 4500 465824463 CHVBK 20180323112145.0 cr unu---uuuuu 170327e19900701xx s 000 0 eng 10.1007/BF00176650 doi (NATIONALLICENCE)springer-10.1007/BF00176650 Production of pectolytic enzymes by Aspergillus niger: effect of inoculum size and potassium hexacyanoferrate II-trihydrate [Elektronische Daten] [Jožica Friedrich, Aleksa Cimerman, Walter Steiner] Summary: The effect of inoculum size and potassium hexacyanoferrate II-trihydrate, K4[Fe(CN)6]·3 H2O (KHCF), on pectinase synthesis by Aspergillus niger in submerged conditions were studied. Experiments were performed in shake flasks and in a 10-1 stirred bioreactor. Spore concentrations in the range 102−108 spores/1 of substrate were tested. Enzyme activity measured by the Apple Juice Depectinizing Assay (AJDA) showed the highest values using the smallest inoculum. Higher spore concentrations led to a 25% or even up to a 50% reduction of activity. Polygalacturonase (PG) activity decreased similarly to AJDA activity with higher inoculum concentration. Pectinlyase (PL) showed the opposite relationship, while pectin esterase (PE) did not show any correlation with inoculum concentration. Experiments in the fermentor using a reduced inoculum of 102 spores/1 showed that the whole process was prolonged in comparison to 108 spores/1 inoculum. A pronounced effect of KHCF on fungal morphology as well as on enzymatic activity was observed. With increased concentration the morphology gradually changed from loose pellets to smaller compact ones. The enzymatic activity was markedly improved. In the bioreactor the amount of biomass was reduced from about g/l to 8 g/l. The activities were improved in comparison to fermentations without KHCF as follows: AJDA from 68 to 112 units (U)/ml, viscosity reduction from 83% to 90%, PG from 0.8 to 3.3 U/ml, PE from 32 to 49 U/ml and PL from 0.05 to 0.12 U/ml. The fermentation time was reduced from 96 to 68 h. Springer-Verlag, 1990 Friedrich Jožica Boris Kidriĉ Institute of Chemistry, Hajdrihova 19, Ljubljana, Yugoslavia aut Cimerman Aleksa Boris Kidriĉ Institute of Chemistry, Hajdrihova 19, Ljubljana, Yugoslavia aut Steiner Walter Institute for Biotechnology, University of Technology Graz, Schlögelgasse 9, Austria aut Applied Microbiology and Biotechnology Springer-Verlag 33/4(1990-07-01), 377-381 0175-7598 33:4<377 1990 33 253 https://doi.org/10.1007/BF00176650 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00176650 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Friedrich Jožica Boris Kidriĉ Institute of Chemistry, Hajdrihova 19, Ljubljana, Yugoslavia aut NATIONALLICENCE 700 1- Cimerman Aleksa Boris Kidriĉ Institute of Chemistry, Hajdrihova 19, Ljubljana, Yugoslavia aut NATIONALLICENCE 700 1- Steiner Walter Institute for Biotechnology, University of Technology Graz, Schlögelgasse 9, Austria aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer-Verlag 33/4(1990-07-01), 377-381 0175-7598 33:4<377 1990 33 253 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer