Production of Volatile Fatty Acids in a Semi-Continuous Dark Fermentation of Kitchen Waste: Impact of Organic Loading Rate and Hydraulic Retention Time

Justyna Swiatkiewicz, Radoslaw Slezak, Liliana Krzystek and Stanislaw Ledakowicz
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Justyna Swiatkiewicz: Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, Lodz University of Technology, Wólczańska 213 str., 90-924 Łódź, Poland
Radoslaw Slezak: Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, Lodz University of Technology, Wólczańska 213 str., 90-924 Łódź, Poland
Liliana Krzystek: Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, Lodz University of Technology, Wólczańska 213 str., 90-924 Łódź, Poland
Stanislaw Ledakowicz: Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, Lodz University of Technology, Wólczańska 213 str., 90-924 Łódź, Poland

Energies, 2021, vol. 14, issue 11, 1-18

Abstract: The aim of the study was to evaluate the possibility of using the process of dark fermentation to convert kitchen waste into valuable volatile fatty acids in a semi-continuous process at different values of the organic loading rate (2.5 and 5.0 gVS/(L × d)) and hydraulic retention time (5 and 10 d) using anaerobic mixed microbial consortia. The experiments were performed in a bioreactor of working volume 8L with pH control. The maximum volatile fatty acids yield in a steady state (22.3 g/L) was achieved at the organic loading rate of 5.0 gVS/(L × d) and HRT of 10 days. The main products of dark fermentation were acetic and butyric acids, constituting, respectively, 35.2–47.7% and 24.1–30.0% of all identified volatile fatty acids. Additionally, at the beginning of the fermentation and in a steady-state condition, the microbial population analysis (16S rDNA) of the fermentation mixture with the most effective volatile fatty acids generation has been performed to monitor the DF microflora development. The dominant microorganisms at a phylum level in a steady state were Firmicutes (44.9%) and Bacteroidetes (30.1%), which indicate the main role of those phyla in the volatile fatty acids synthesis.

Keywords: volatile fatty acids; dark fermentation; mixed microbial cultures; metagenomic analysis (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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