Acetate kinase activity test - a new approach to biogas production monitoring in the presence of chlorophenols

The proper functioning of processes related to the use of alternative energy sources is one of the key aspects in the field of biotechnology. Therefore, there is a need to develop new techniques allowing the adequate monitoring of the biogas production, especially in the presence of potentially inhibiting substances. The negative impact of chlorophenols on methane fermentation proces was confirmed in numerous studies. The inhibition effect is usually monitored based on chemical and microbiological assessment. However, the results of the tests sometimes do not reflect adequately the actual process. In this research the acetate kinase activity test was proposed as a sensitive control parameter for the monitoring of biogas production in the presence of 2,4-dichlorophenol. Acetate kinase can be considered a key enzyme in methanogenesis. The determination of its activity is simpler and less time consuming compared to other monitoring methods. The amount of the iron acetyl hydroxyamine complex measured in the proposed assay corresponds to the amount of acetyl phosphate formed during the methane fermentation. It was revealed that the acetate kinase activity can better reflect the changes in biogas yield and in methane concentration compared with chemical and microbiological analyses as well as the total dehydrogenase activity tests. Keywords: 2,4-dichlorophenol; Methane fermentation; Biogas production monitoring; Acetate kinase