The effect of mixed-enzyme addition in anaerobic digestion on methane yield of dairy cattle manure

SUTARYO, Sutaryo and WARD, Alastair James and MOLLER, Henrik Bjarne (2014) The effect of mixed-enzyme addition in anaerobic digestion on methane yield of dairy cattle manure. Environmental Technology, 35 (19). pp. 2476-2482. ISSN 0959-3330


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This study investigates the effect of applying a mixture of enzymes (ME) to dairy cattle manure (DCM) as substrate in anaerobic digestion (AD). The aims of this study were to evaluate different methods of ME application to DCM at different temperatures and to investigate the effect of adding ME during the pre-treatment of the solid fractions of dairy cattle manure (SFDCM). The results showed that there was no positive effect of direct ME addition to substrate at either mesophilic (35 C) or thermophilic (50 ◦ C) process temperatures, but there was a significant 4.44% increase in methane yield when DCM, which had been incubated with ME addition at 50 ◦ C for three days, was fed to a digester when compared to a control digester operating at the same retention time. Methane production was detected during the pre-treatment incubation, and the total sum methane yield during pre-treatment and digestion was found to be 8.33% higher than in the control. The addition of ME to the SFDCM in a pre-incubation stage of 20 h at 35 ◦ C gave a significant increase in methane yield by 4.15% in a digester treating a mixed substrate (30% liquid fractions DCM and 70% enzyme-treated SFDCM) when compared with the control digester treating a similar mixed substrate with inactivated enzyme addition. The results indicate that direct physical contact of enzyme molecules and organic material in DCM prior to AD, without the intervention of extracellular enzymes from the indigenous microorganism population, was needed in order to increase methane yields. Keywords: biogas; mixed enzymes; pre-treatment; incubation; manure

Item Type:Article
Subjects:S Agriculture > SF Animal culture
Divisions:Faculty of Animal and Agricultural Sciences > Department of Food Technology
ID Code:51697
Deposited By:Mr. Perpus FP Admin
Deposited On:31 Jan 2017 10:53
Last Modified:31 Jan 2017 10:53

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