4 research outputs found
Syntrophic Butyrate-Oxidizing Consortium Mitigates Acetate Inhibition through a Shift from Acetoclastic to Hydrogenotrophic Methanogenesis and Alleviates VFA Stress in Thermophilic Anaerobic Digestion
In anaerobic digestion (AD), butyrate is degraded by syntrophic consortium, but can accumulate in highly loaded AD systems. The effect of butyrate on the AD process attracts much less attention than propionate or acetate. In this work, an enrichment culture of the thermophilic butyrate-oxidizing syntrophic consortium was obtained by gradually increasing the initial butyrate concentration from 20 to 170 mM. Surprisingly, even the highest butyrate concentration did not significantly inhibit the methanogenic community, and the stage of acetate degradation was the limiting overall rate of the process. At 170 mM butyrate, the bacterial community changed towards the dominance of syntrophic acetate-oxidizing (SAO) bacteria related to Syntrophaceticus (42.9%), Syntrophomonas (26.2%) and Firmicutes (26.2%), while the archaeal community experienced a sharp decrease in the abundance of Methanosarcina thermophila (from 86.0 to 25.0%) and increase in Methanothermobacter thermautotrophicus (from 3.2 to 53.1%) and Methanomassiliicoccus (from 3.2 to 21.9%). Thus, the shift from acetoclastic methanogenesis to SAO coupled to hydrogenotrophic methanogenesis occurred as an adaptive strategy to overcome high acetate (~200 mM) build-up. Bioaugmentation with the obtained enrichment culture was effective in mitigating the butyrate-dominated VFA build-up during the AD of readily biodegradable waste, increasing the methane production rate, methane yield and volatile solids removal by more than 3.5, 6.2 and 2.9 times, respectively. Our study revealed that the thermophilic butyrate-oxidizing consortia as bioaugmented culture could be the potential strategy to alleviate the high organic load and VFA stress of AD
Use of Polyguanidine-Derivatives-Based Biocides for Microbial Growth Inhibition and for the Development of A Novel Polyethylene-Based Composite Material Resistant to the Formation of Multispecies Microbial Biofilms
This study aimed to investigate the dependence of the biocidal activity of polyguanidine (co)polymers on their structure during the formation of biofilms by active PE-degrading cultures of model microorganisms. The Bc-2 copolymer of methacryloyl guanidine hydrochloride (MGHC) and diallyldimethylammonium chloride (DADMAC), which suppressed both the formation of biofilms and the growth of planktonic cultures, exhibited the highest activity. When PE was exposed in tropical soil, the composition of the microbial community on the PE surface differed significantly from that of the community in the surrounding soil. In particular, the proportion of Actinobacteria increased from 7% to 29%, while the proportion of Bacteroidetes decreased from 38% to 8%.
Keywords: biofilms, polyhexamethylene guanidine salts, dynamics of biofilm formation, antibiofilm effect, composite material
Recommended from our members
Hybrid Iodide Perovskites of Divalent Alkaline Earth and Lanthanide Elements
Hybrid Iodide Perovskites of Divalent Alkaline Earth and Lanthanide Elements
Hybrid halide perovskites AMIIX3 (A = ammonium
cation, MII = divalent cation, X = Cl, Br, I) have been
extensively studied but have only previously been reported for the
divalent carbon group elements Ge, Sn, and Pb. While they have displayed
an impressive range of optoelectronic properties, the instability
of GeII and SnII and the toxicity of Pb have
stimulated significant interest in finding alternatives to these carbon
group-based perovskites. Here, we describe the low-temperature solid-state
synthesis of five new hybrid iodide perovskites centered around divalent
alkaline earth and lanthanide elements, with the general formula AMIII3 (A = methylammonium, MA; MII = Sr,
Sm, Eu, and A = formamidinium, FA; MII = Sr, Eu). Structural,
calorimetric, optical, photoluminescence, and magnetic properties
of these materials are reported