Effect of humic acids on the activity of pure and mixed methanogenic cultures

Journal article (2017)

Authors

A.F. Khadem Wageningen University & Research, Sanitary Engineering - CEG
Samet Azman Wageningen University & Research
Caroline M. Plugge Wageningen University & Research
Grietje Zeeman Wageningen University & Research
J.B. van Lier Sanitary Engineering - CEG
Alfons J M Stams Wageningen University & Research
Research Group
Sanitary Engineering (CEG) (TU Delft)
Humic acid Inhibition Methanogenesis Activity tests Anaerobic sludge
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Published Date

01-04-2017

Language

English

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Faculty

Civil Engineering & Geosciences

Department

Water Management

Research Group

Sanitary Engineering

Abstract

The impact of humic acid (HA) on methanogenic activity was investigated. Methanogenic crushed granular sludge and pure cultures of mesophilic methanogens were incubated in batch cultures with HA. Initial methane production rates and substrate consumption rates were quantified. In the presence of 1 kg m−3 HA, the methane production rate of all hydrogenotrophic methanogens was inhibited by more than 75%, except Methanospirillum hungatei that was not inhibited up to 5 kg m−3 HA. The acetoclastic Methanosarcina barkeri was completely inhibited by HA ≥1 kg m−3. However, Methanosaeta concilii was only slightly affected by HA up to 3 kg m−3. When methanogenic granular sludge was incubated with HA, the specific methanogenic activity (SMA) tests showed less inhibition, when compared to the pure cultures of methanogens. The SMA test with H2/CO2, formate and acetate showed reduced initial methane production rate of 42%, 23% and 40%, respectively. Differences in HA susceptibility were explained by differences in cell wall structure.