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Thermophilic anaerobic digestion of source-sorted household solid waste: the effects of enzyme additions

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Original languageEnglish
Pages (from-to)916-919
Number of pages4
JournalApplied Microbiology and Biotechnology
Issue number6
Publication statusPublished - Feb 1994
Externally publishedYes
Publication typeA1 Journal article-refereed


Thermophilic (55° C) methanation of source-sorted household solid waste (HSW) was studied in batch and in continuous experiments. Furthermore, the effects of additions of xylanase, lipase, protease and a mixture of these on the methanation were tested. In the batch studies, comparative assays with active and inactive enzymes were used to elucidate the role of the added enzymes. The results showed that the HSW was readily digestible, up to 400-590 mlCH4·g-1 volatile solids (VS) was produced. Only with protease added, at a concentration of 1.1 Anson protease units·kg-1 VS was a higher specific methanogenic activity found with active enzymes compared to inactive (autoclaved) enzymes or without enzyme addition. The methane yield by conversion of the HSW in the batch assays and in the reactor studies was not increased by enzyme additions (enzyme mixture).