Effect of medium pH on chemical selectivity of oxalic acid biosynthesis by Aspergillus niger W78C in submerged batch cultures with sucrose as a carbon source

Ewa Walaszczyk , Waldemar Podgórski , Małgorzata Janczar-Smuga , Ewelina Dymarska


The pH of the medium is the key environmental parameter of chemical selectivity of oxalic acid biosynthesis by Aspergillus niger. The activity of the enzyme oxaloacetate hydrolase, which is responsible for decomposition of oxaloacetate to oxalate and acetate inside the cell of the fungus, is highest at pH 6. In the present study, the infuence of pH in the range of 3–7 on oxalic acid secretion by A. niger W78C from sucrose was investigated. The highest oxalic acid concentration, 64.3 g dm−3, was reached in the medium with pH 6. The chemical selectivity of the process was 58.6% because of the presence of citric and gluconic acids in the cultivation broth in the amount of 15.3 and 30.2 g dm−3, respectively. Both an increase and a decrease of medium pH caused a decrease of oxalic acid concentration. The obtained results confrm that pH 6 of the carbohydrate medium is appropriate for oxalic acid synthesis by A. niger, but the chemical selectivity of the process described in this paper was high in comparison to values reported previously in the literature.
Author Ewa Walaszczyk (EaE / IChaFT / DBaFA)
Ewa Walaszczyk,,
- Department of Biotechnology and Food Analysis
, Waldemar Podgórski (EaE / IChaFT / DBaFA)
Waldemar Podgórski,,
- Department of Biotechnology and Food Analysis
, Małgorzata Janczar-Smuga (EaE / IChaFT / DAOFT)
Małgorzata Janczar-Smuga,,
- Department of Animal Origin Food Technology
, Ewelina Dymarska (EaE / IChaFT / DAEaQA)
Ewelina Dymarska,,
- Department of Agricultural Engineering and Quality Analysis
Journal seriesChemical Papers, ISSN 2585-7290, e-ISSN 1336-9075, (A 20 pkt)
Issue year2018
Publication size in sheets0.5
Keywords in EnglishOxalic acid · Aspergillus niger · Biosynthesis · pH · Chemical selectivity
ASJC Classification2505 Materials Chemistry; 2209 Industrial and Manufacturing Engineering; 1500 General Chemical Engineering; 1303 Biochemistry; 1600 General Chemistry
Languageen angielski
Walaszczyk_Podgorski_Janczar_Smuga_Dymarska_Effect_Of_Medium_Ph_On_Chemical_Selectivity.pdf 830,73 KB
Score (nominal)20
Score sourcejournalList
Publication indicators WoS Citations = 1; Scopus SNIP (Source Normalised Impact per Paper): 2018 = 0.421; WoS Impact Factor: 2017 = 0.963 (2) - 2017=1.198 (5)
Citation count*3 (2020-08-08)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.