Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

Bioengineering

Samet Azman³  Ahmad F. Khadem³  Grietje Zeeman²  Jules B. van Lier¹  Caroline M. Plugge³ 

[1] Section Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2600 GA Delft, The Netherlands; E-Mail:;Sub-Department of Environmental Biotechnology, Wageningen University, 6700 AA Wageningen, The Netherlands; E-Mail:;Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands; E-Mails:

关键词: cellulose;    anaerobic digestion;    humic acid;    hydrolysis;    inhibition;    mitigation;    salt addition;    cations;   

DOI  :  10.3390/bioengineering2020054

来源: mdpi

【 摘 要 】

Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C) and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.