Effect of magnetite on anaerobic digestion of distillers grains and beet pulp: Operation of reactors and microbial community dynamics

• Published in: Journal of bioscience and bioengineering Vol. 131; no. 3; pp. 290 - 298
• Main Authors: Ziganshina, Elvira E., Belostotskiy, Dmitry E., Bulynina, Svetlana S., Ziganshin, Ayrat M.
• Format: Journal Article
• Language: English
• Published: Japan Elsevier B.V 01-03-2021
• Subjects: 16S rRNA gene; Anaerobic digestion; Anaerobiosis - drug effects; Beet pulp; Beta vulgaris - chemistry; Bioreactors - microbiology; Distillers grains; Ferrosoferric Oxide - pharmacology; Magnetite; mcrA gene; Methane - biosynthesis; Microbial community dynamics; Microbiota - drug effects; RNA, Ribosomal, 16S - genetics; Distillers grains; Magnetite; Microbial community dynamics; mcrA gene; Beet pulp; Anaerobic digestion; 16S rRNA gene
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2020.10.003

It has been previously shown that magnetite (Fe3O4) nanoparticles stimulate the anaerobic digestion process in several anaerobic reactors. Here we evaluate the effect of magnetite nanoparticles on the efficiency of anaerobic digestion of distillers grains with solubles and sugar beet pulp in mesophilic batch experiments. The addition of magnetite nanopowder had a positive effect on the anaerobic digestion process. CH4 was produced faster in the presence of 50 mg of Fe3O4 per 1 g of added total solids than from treatments without addition of Fe3O4. These results demonstrate that the addition of magnetite enhances the methanogenic decomposition of organic acids. Microbial community structure and dynamics were investigated based on bacterial and archaeal 16S rRNA genes, as well as mcrA genes encoding the methyl-CoM reductase. Depending on the reactor, Bacteroides, midas_1138, Petrimonas, unclassified Rikenellaceae (class Bacteroidia), Ruminiclostridium, Proteiniclasticum, Herbinix, and Intestinibacter (class Clostridia) were the main representatives of the bacterial communities. The archaeal communities in well-performed anaerobic reactors were mainly represented by representatives of the genera Methanosarcina and Methanobacterium. Based on our findings, Fe3O4 nanoparticles, when used properly, will improve biomethane production.